NASA Technical Memorandum 112214

Acceleration Tolerance: Effect of Exercise, Acceleration Training; Bed Rest and Weightlessness Deconditioning A Compendium of Research (1950-1996)

J. L. Chou, M. A. McKenzie, N. J. Stad, and P. R. Barnes, California State University at San Francisco

C. G. R. Jackson, California State University at Fresno

F. Ghiasvand and J. E. Greenleaf, Ames Research Center, Moffett Field, California

October 1997

National Aeronautics and Space Administration Ames Research Center Moffett Field, California 94035-1000

Contents

Page

Summary ...... iv Introduction ...... v Abstracts and Annotations ...... 1

Additional Selected Bibliography ...... 45 Author Index ...... 47

Keyword Index ...... 51

iii Summary This compendium includes abstracts and annotations of clinical observations and of more basic studies involving physiological mechanisms concerning interaction of acceleration, training and deconditioning. If the author's abstract or summary was appropriate, it was included. In other cases a more detailed annotation of the paper was prepared under the subheadings Purpose, Methods, Results, and Conclusions. Author and keyword indices are provided, plus an additional selected bibliography of related work and of those papers received after the volume was prepared for publication. This volume includes material published from 1950-1996.

iv Introduction

The purpose of this compendium is to present summaries of clinical observations and results from more basic studies that help to elucidate physiological mechanisms for control of acceleration tolerance as affected by exercise training and deconditioning. It the author's abstract or summary was appropriate, it was utilized. In some cases a more detailed annotation was provided under the subheadings Purpose, Methods, Results, and Conclusions. This volume includes studies published from 1950 through 1996. Author and keyword indices are provided. The material is listed in alphabetical order by first author and numbered consecutively by abstract number, not page number. We thank our many colleagues who sent us reprints, and apologize to those whose work we have inadvertently overlooked. The authors thank Esther Johnson for valuable technical assistance.

J.E.G.

1. Antonutto G, D Linnarsson, CJ Authors' Abstract Sundberg, PE diPrampero. The goal of this study was to provide Artificial gravity in Space: vestibular information for developing means to protect tolerance assessed by human operators from +Gz acceleration. A total of centrifuge spinning on Earth. 36 subjects, aged 20 to 31, participated in the Acta Astronautica 27:71-73. 1992. study. All had been certified fit for Authors' Abstract centrifugation and hypokinesia with head- Artificial gravity created by the astronauts down tilt. Three conditions were run. In the themselves, without any external power first, 10 subjects s_nt 60 hours in supply, by pedalling on a couple of hypokinesia with -60 head-down tilt during counterrotating bicycles along the inner wall the night and -150 during the day. Before of the space module (Twin Bikes System, and after this treatment, subjects' endurance TBS), was previously suggested (Antonutto of +3Gz was assessed for 15 minutes with et al., 1991) to prevent musculo-skeletal and without antigravity device I (AGD-1). decay and cardiovascular deconditioning In the second condition, the effectiveness of during long term space flights. To AGD-1 was tested on 24 subjects before and investigate whether this unusual rotating after a 7-day period of hypokinesia with environment would determine abnormal head-down tilt (-10°). The following stimulations of the vestibular system due to acceleration schedule was used: 2.5- and 3.0- Coriolis cross coupled accelerations, thus G for 5 minutes each, 3.5-, 4.0- and 4.5-G leading to acute motion sickness (AMS), the for 30 minutes each. In the third condition, conditions of a rotating environment were endurance of 6 subjects was measured before reproduced in a human centrifuge. A and after a 7-day period of hypokinesia using cycloergometer was fixed to the arm of the the AGD-2 device and the same acceleration centrifuge, the rotation speed of which was schedule as in condition 2. In all cases, equal to that yielding 1 g at the feet level in acceleration increased at a rate of 0. I-G per the TBS (i.e. ranging from 19 to 21 RPM). second. AGD-I consisted of closely fitting The ergometer position was such that the trousers made of stretch fabric with a high combination of the horizontal and elasticity modulus which could maintain the gravitational acceleration vectors was 1.414 perimeter and volume of the lower body at the inner ear level and was aligned along under exposure to longitudinal G-load. the head to feet axis. Three subjects, AGD-2 was a shortened modification of pedalling at 50 W on a cycloergometer during AGD-1 reaching to the knees. Operator centrifuge's spinning, were asked to move performance was evaluated in condition 3 the head following an AMS' provocation during exposure to acceleration with a control protocol. None of them developed any AMS task using a flight instrument providing symptoms. This supports the look of the information about flight parameters. TBS as tool for avoiding musculo-skeletal Physiological parameters were assessed by and cardiovascular deconditioning during an EKG with tetrapolar chest leads, long term space flights. photoplethysmography of the ear, and a myogram of the femur and abdominal muscles. Subjects were all trained to criterion on the control task before • Asyamolov BF, LI Voronin, VS Panchenko, NV Ulyatovsiy, centrifugation. RA Bondarenko, AV Kaliberdin, SYu Elizarov, VG 3. Balldin UI, K Myhre, PA Tesch, PIokhova, AS Yarov. U Wilheimsen, HT Andersen• Effectiveness of antigravity devices of Isometric abdominal muscle training the chamberless type after 7 days of and G tolerance. hypokinesia with head-down tilt. Aviation, Space, and Environmental Kosmicheskaya Biologiya i Medicine 56: 120-124, 1985. Aviakosmicheskaya Meditsina Authors' Abstract 22:37-40, 1988. Methodsto increaseG toleranceof pilots during submaximal G exposures may be used flying highperformanceaircraftareof vital as indicators of shifts in endurance G importance.Strainingmaneuversto increase tolerance. The procedure may reduce the G toleranceinvolveabdominalmuscles,and need for exhaustive G tolerance tests with highintra-abdominalpressures(IAP) are associated risks and discomfort. recordedduring G exposure. This study was carried out to examine the effects of an 11- 5. Beckman MC, KR Coburn, RM week abdominal muscle training program on Chambers, RE DeForest, WS maximal IAP, G tolerance and muscle Augerson, VG Benson. strength/endurance in 10 fighter pilots. G Physiological changes observed in tolerance was measured in a human human subjects during zero G centrifuge using simulated aerial combat stimulation by immersion in water up maneuvers (ACM). The pilots had a higher to neck level. maximal IAP before training than a control Aerospace Medicine 32:1031-1041, group. G tolerance, maximal lAP, and 1961. maximal peak torque of knee extensors were Authors' Abstract not changed by the training. In contrast, leg Knowledge relative to the effects of muscle endurance increased (p<0.01) and prolonged weightlessness is needed in ratings of local perceived exertion decreased preparing man for space flight. The buoyant (p<0.01). Static endurance of the knee force exerted upon immersed bodies extensors was positively correlated (p<0.05) effectively simulates the weightless state with with G tolerance. It is concluded that the respect to proprioceptive sensory responses present abdominal training program, and perhaps in other ways. An investigation employed in experienced fighter pilots, is not into the physiological effects of immersing sufficient to increase IAP or G tolerance. subjects in water up to neck level was undertaken. It was found that water 4. Balidin UI, P Kuronen, H Rusko, immersion produces an unnatural E. Svensson. physiological situation in that, during Perceived exertion during respiration, the inspired air inflates the lungs submaximal G exposures before and to atmospheric pressure while the external after physical training. pressure against the chest, abdomen, and Aviation, Space, and Environmental legs, due to the water, is greater than Medicine 65:199-203, 1994. atmospheric. This situation is equivalent to Authors' Abstract "negative pressure breathing." Ratings of perceived exertion (RPE) were A series of experiments involving seven registered at submaximal levels in G subjects immersed in water up to neck level endurance tests of a combined strength and for periods of 5 to 23 hours (five subjects for endurance training program in 17 pilots. 12 hours) showed a significant weight loss After 12 months of physical training, the during the period of immersion, which was endurance G tolerance (time to exhaustion explained by the diuresis which occurred. during simulated aerial combat maneuver), Pulmonary volume measurements showed a increased by a mean of 40% (p<0.001), decrease in the expiratory reserve volume and while the mean RPE at 5 rain submaximal G in the respiratory minute volume during exposure decreased by 1.2 units (p<0.02). immersion. There was no significant Following 12 months of physical training, a decrement in the performance of a tracking significant relationship was observed task, attributable to the water immersion, between the improvement of the endurance G during exposure to a simulated space vehicle tolerance and the decrease of the RPE at 5 reentry deceleration profile. Exposure to 4.5 min (p = 0.05). Mean SaO 2 at 5 rain positive G for 15 seconds following water increased from 84 to 90% (p<0.01) after immersion revealed a decrement in tolerance training, while heart rate responses to G in most subjects. stress did not change. It is concluded that 1. Immersion of subjects in water up to mean RPE and, to some extent, mean SaO 2 neck level produced a continuous diuresis presumablyon thebasisof theGauer-Henry loads on the bicycle ergometer while in the left atrialvolumereceptorreflex. sitting position at +3 G z, the oxygen 2. Immersionin waterupto necklevel transport to working muscles is limited causeschangesin pulmonary primarily by disturbances in the pulmonary compartmentationrepresentedbya slight gas exchange; the exaggerated hydrostatic decreasein vital capacity,decreasein the pressure differences in this condition present expiratoryreservevolumeswith anincrease a greater handicap to the pulmonary than the in theinspiratoryvolume,andadecreasein systemic circulation. tidal volumewhichis compensatedfor by an increasein respiratoryrate. 7. Bulbulian R. 3. Immersionof subjectsin waterup to Physical training and +Gz tolerance necklevelfor periodsof 12to 23hours reevaluted. resultedin adecreasein toleranceto positive Aviation, Space, and Environmental acceleration. Medicine 57:709-711, 1986. 4. Immersionof subjectsin waterup to Author's Abstract necklevelfor 12hoursproducedamoderate The effect of physical training on +Gz changein ability toperformatrackingtask tolerance is of vital interest in the aerospace during exposureto 8 G,transverse community. The data on the effect of acceleration,butwithoutsignificantchangein physical training on orthostatic tolerance or physicalability to toleratethisacceleration. simulated air combat maneuvers are equivocal. The effects of aerobic and 6. Bjurstedt H, G Rosenhamer, O strength training programs are briefly Wigertz. reviewed. The data suggest a need for High-G environment and responses careful reinterpretation of research results in to graded exercise. light of conflicting reports and Journal of Applied Physiology methodological shortcomings. Aerobic 25:713-719, 1968. training cannot be assumed to always be Authors' Abstract detrimental nor can strength training be Ventilatory and circulatory responses to assumed to be universally effective in graded leg exercise on a bicycle ergometer improving +Gz tolerance. In selecting (300, 600, and 900 kpm/min, i.e., 49, 98, appropriate screening criteria and training and 147 W, for 6 min at each work load) regimens for aircraft personnel, it seems were studied in eight healthy, untrained prudent to reinvestigate strength and subjects in the sitting position at normal endurance training effects on +Gz tolerance gravity (+1 Gz) and at +3 G z. The effect of using multivariate research paradigms. increased G on the average work performed Special attention should be directed to by the leg muscles was calculated to be commonly accepted physiological principles negligible. At the highest work load, mean which may vary under conditions of altered expired minute volume, oxygen uptake, heart gravitation. rate, and arterial lactate levels for the 6t" min of exercise were 19.6 liters/min, 241 ml/min, 8. Chase GA, C Grave, LB Rowell. 32 beats/min, and 1.43 mM/liter higher at +3 Independence of changes in G z than at +1 Gz; the increases were functional and performance capacities statistically significant except for arterial attending prolonged bed rest. lactate. No electrocardiogram (ECG) Aerospace Medicine 37: 1232-1238, abnormalities occurred at +3 G z even at the 1966. highest work load. An increase in the work Authors' Abstract load from 600 to 900 kpm/min at +3 G z Eighteen young men were studied before caused leveling off of oxygen uptake and rise and after 15 and 30 days bed rest to examine of arterial lactate in two subjects and, in the effects of absolute bed rest and recumbent another, inability to complete the work exercise during bed rest on the pulse rate because of exhaustion. It is concluded that response to submaximal work, during leg exercise with increasing work cardiovascular functional capacity (max 902 ), physicalwork capacity,and to accelerations. This test can be made in orthostatictolerance.Changesin the small-volume chambers, in bed, in a fixed submaximalpulserateasaresultof the position, or in a spacesuit. conditionsof thisstudydid notpredictthe 10. Clark WG, IDR Gardiner, AK trendin eitherwork capacityor max 902 Mclntyre, H Jorgenson. whereas,changesin work capacityoccurred The effect of positive acceleration on independentlyof changesin max 902 and fluid loss from blood to tissue spaces viceversa.Thehighest902 attainable in human subject on the centrifuge. duringexerciseto exhaustiononabicycle Federation Proceedings 5: 17-18, 1956. ergometerunderestimatedmax902 4 to 23 (Abstract) percent. Whenrecumbentexercisewas Authors' Abstract carriedout duringbedrest,thedifferencein As estimated by hematocrits and plasma thehighest'_O2 attainableonabicycle protein determinations, fluid loss from blood ergometerandthemax 902 wasdecreased to tissue spaces occurred in six seated human subjects on the centrifuge. At near blackout afterbedrestby anincrementin "_/O2 during levels of G (3.5 to 5.0 G) maintained for 3-5 thebicycletest. Unlessmax'v'O2 was minutes, a significant loss of fluid (3.6-4.5 increasedduringbedrest,subjectshad cc./100 cc. blood; or 216-270 cc. total) was decreasedadaptabilityto postureafterward. found. The loss in four subjects exposed to 4 G for 5 minutes was reduced by anti-G 9. Cherepakhin MA. suits to an average of 75% (range 28-96%) of Effectof areduceddiet and their loss when unprotected. In two cases hypokinesiaon humantoleranceto subjected to 3.5 G for 5 minutes, the loss staticloads. was less than that of the four subjects Kosmicheskaya Biologiya i exposed to 4.0 G for 5 minutes. In one Meditsina subject submitted to 5 G for 3 minutes, the 4:67-72, 1970. loss was less than that he obtained at 4 G for Author's Abstract 5 minutes, although after-effects were noticed Three series of experiments, each 15 days in vision. A smaller loss ( 132 cc. total) in duration, were ran; there were 18 subjects occurred in one of the subjects who had 30 in the age group 24-27 years. In all the runs of 4.7 G for 10 seconds with a 2 minute experiments the subjects were fed a ration of interval between runs, than occurred in the 1,800 Cal/day consisting of lyophilized same subject after a 5 minute uninterrupted foods. In the first series the motor activity run at 4.0 G (288cc.). regime was unrestricted. In the second series At 4.0 G, the fluid losses observed were the subjects adhered to a rigorous bed much less than those reported elsewhere for confinement. In the third series the centrifuged dogs, but recovery occurred more conditions differed from those in the second rapidly. The losses also were less than those in that before and after the experiments the reported elsewhere for postural changes of test subjects were exposed to accelerations in humans from the recumbent to the upright a chest-to-back direction (8 g) for a period of positions. It is unlikely that fluid losses due 120 seconds. A diet of lyophilized foods (15 to G contribute to any fatiguing effects or days, 1,800 Cal) with a normal motor activity detrimental residual effects possibly resulting regime exerts no effect on man's tolerance to from positive acceleration experienced by test static loads. Hypokinesia in the form of pilots or fighter pilots in combat. bedrest confinement for 15 days with a diet of lyophilized foods in a quantity of 1,800 11. Cooper KH, S Leverett. Cal/day exerts a negative effect on man's Physical conditioning versus +Gz tolerance to stress. A static functional test tolerance. consisting of isometric exercise can be Aerospace Medicine 37:462-465, recommended for predicting man's tolerance 1966. Authors' Abstract Naval Aerospace Medical Research An attempt was made in this study to Laboratory, NAS, Pensacola, FL. determine the effect of endurance training on +Gz tolerance in experienced centrifuge subjects. Eleven subjects were divided into 13. Dlusskaya IG, MN Khomenko. six exercisers and five controls. For three Distinctions in reactions to active months the exercisers engaged in a daily (5 orthostatic and water-loading tests of times a week) progressive running program subjects differing in tolerance to +Gz while the controls were asked to avoid accelerations. vigorous exercise. Frequently during this Kosmicheskaya Biologiya i period, all eleven subjects were subjected to Aviakosmicheskaya Meditsina both rapid onset and gradual onset runs on 19:22-27, 1985. the USAF School of Aerospace Medicine Authors' Abstract centrifuge. At the conclusion of the three Thirty-seven healthy male test subjects, months, significant differences were noticed aged 19-21, with different +Gz acceleration between the exercise and control groups in tolerance were examined. Their blood endurance capacity as indicated by an pressure (BP) and heart rate (HR) during 5- increase in maximal oxygen consumption. min tilt tests and 2% water loading tests were However, no significant difference was noted measures 2-3 weeks prior to centrifugation. between the two groups in their ability to Quantitative evaluation of orthostatic tolerate positive Gs during either gradual or tolerance using an orthostatic index and BP rapid onset centrifuge runs. and HR responses to tilt tests before and after In this study, neither an increase nor a water loading revealed specific features of decrease in +Gz tolerance could be correlated cardiovascular regulation in the subjects with with endurance capacity. high and low +Gz acceleration tolerance. The negative predictive indicators include: 12. Crisman RP, RR Burton. decreased BP, HR and cardiac index in the Physical fitness program to enhance supine position in combination with high aircrew G tolerance. orthostatic tolerance, as well as decreased Brooks Air Force Base, TX: orthostatic tolerance in combination with a USAF School of Aerospace lower function of vasoconstrictor Medicine, mechanisms in the upright position and a USAFSAM-SR-88-1, 1988.50p. lower sensitivity of carotid sinus reflexes to Authors' Abstract blood volume changes during tilt and water A physical fitness program of resistance loading tests. When examining test subjects training, such as weight lifting, directed with high +Gz tolerance, preference should toward increasing strength and anaerobic be given to those who can well tolerate tilt capacity will increase G-duration tolerance. tests and show moderately high BP and HR This tolerance increase is particularly useful in the supine position, as well as to those for USAF/USN pilots flying high- who exhibit a noticeable increment of performance fighters during aerial combat diastolic BP during 5-min tilt tests. maneuvers. A weight-training program including exercise equipment to be used by 14. Epperson WL, RR Burton, EM Bernauer. aviators to increase (and maintain this increase) their strength and anaerobic capacity The effect of physical conditioning on +Gz tolerance. is described. Aerobics conditioning with precautions and limitations for G tolerance is Aerospace Medical Association discussed. Figures show recommended Preprints, 1977. p. 82-83. weight-training exercises. This special report (Abstract). is a combined U.S. Air Force and U.S. Navy Authors' Abstract effort that came from a 1987 Joint-Service G- New high performance aircraft are Tolerance Conference that was hosted by the capable of developing levels of high sustained G that places increased G-tolerance demandson pilots. It isimportant,therefore, increased at an average rate of 4 s/week that methodsbe foundfor improvingG during the course of the experiment. On the tolerancein thepilot population.Several other hand, the weight trainers increased their possibilitiesexist;however,oneof themost G tolerance at an average rate of 15 s/week. promisingnow availableto thepilot isa The difference between group W, compared physicalconditioningprogram.Yet little is with groups C and R, was statistically knownaboutthetypesof physicalexercises significant at the 5% level. Fatigue scores which would bebestsuitedto increaseG- indicate that group W subjects take longer to tolerance.Consequently,a studywas reach a given level of fatigue than did the conductedtodeterminetheinfluenceof 2 subjects of the other groups. It appears typesof physicalconditioningprogramson therefore that a physical conditioning G-tolerance,asmeasuredin 26 youngmen, program of weight training will improve usingthecentrifugeattheUSAFSchoolof human tolerance to aerial combat maneuvers. AerospaceMedicine(SAM), BrooksAFB, Texas. G-tolerancewasmeasuredasthe 16. Epperson WL, RR Burton, EM durationthesubjectcontinuedtheacceleration Bernauer. profile-calledthesimulatedaerialcombat The effectiveness of specific weight maneuver(SACM)-untilhebecamefatigued. training regimens on simulated aerial Duringexposureto theSACM thesubject combat maneuvering G tolerance. woreastandardUSAFanti-Ggarmentand Aviation, Space, and Environmental performedtheM-1 strainingmaneuveras Medicine 56:534-539, 1985. necessaryto maintainvision. TheSACM Authors' Abstract consistedof alternating15secplateausof To assess the effectiveness of muscle- +4.5Gz and+7.0 Gz,continuinguntil the strength (weight training) on simulated aerial subjectchoseto halttherun-usuallyhispoint combat maneuvering (SACM) G tolerance, of fatigue. seven young men were exposed to a 12-week program of whole-body weight training in 15. Epperson WL, RR Burton, EM which were measured strengths of various Bernauer. muscle groups, body circumferences, body The influence of differential physical mass, and the percentage of body fat. The conditioning regimens on simulated magnitudes of the weights used in training aerial combat maneuvering tolerance. were used to measure muscle strength and Aviation, Space, and Environmental were compared and correlated with each Medicine 53:1091-1097, 1982. subject's SACM tolerance--defined as the Authors' Abstract total time that a subject could withstand The influence of physical conditioning on continuous exposure to a 4.5 and 7.0 +Gz tolerance to a centrifugation profile called the centrifuge profile using fatigue as his Simulated Aerial Combat Maneuvering voluntary endpoint. Chest and biceps (SACM)--was determined using 24 young circumferences increased 4.2% and 3.1%, men as subjects. These subjects were respectively; abdomen and thigh assigned to groups as controls (no physical circumferences did not significantly change; training, C), runners (R), and weight trainers body fat decreased 16.8%; and body mass (W). They followed a 2-week protocol of increased 2.3%. Abdominal (sit ups) and specified physical training. During this biceps (ann curl) strengths increased 99% study, tolerance to the SACM, maximum and 26.2%, respectively, and were highly oxygen consumption, muscle strength, and correlated with SACM tolerance time body composition were periodically (p<0.01); leg (leg press) and chest strengths determined. SACM tolerance was defined as (bench press) made less significant the total time that a subject could withstand contributions to the SACM tolerance time. A continuous exposure to a 4.5 and 7.0 +Gz net increase in SACM tolerance times of 53% centrifugation profile as determined by his resulted from weight-training. Multiple voluntary endpoint of fatigue. The +Gz regression analysis of all four muscle groups tolerance of the runners and controls between weeks l and 12 with the SACM

6 tolerancehadacorrelationof determinationof Some human reactions to prolonged 0.61. centripetal accelerations [+Gz] of low intensities. 17. Forster EM, JE Whinnery. Kosmicheskaya Biologiya i Dynamic cardiovascular response to Aviakosmicheskaya Meditsina +Gz stress in aerobically trained 10:35-40, 1976. individuals. Authors' Abstract Aviation, Space, and Environmental The effect of centripetal accelerations Medicine 61:303-306, 1990. (+Gz) of low intensities (0.5-0.6 g) imparted Authors' Abstract for four days against a background of relative Very high onset sustained +Gz stress hypokinesia was investigated. Peripheral and requires rapid cardiovascular response to intracranial circulation, equilibrium function support human tolerance. This study was and morphological composition of the conducted following a previous study capillary blood were examined. During the concerning +Gz tolerance in aerobically first three days of centrifuging the trained individuals, and was initiated to hemodynamic state differed insignificantly determine if intense aerobic conditioning from the initial level. On the fourth day signs might affect cardiovascular +Gz tolerance of cardiovascular deconditioning were found. through reduction in heart rate response to This was indicated by the orthostatic test. +Gz stress. The study compared heart rate Changes in the peripheral blood indicated a response data on 22 aerobically trained moderate stress reaction which persisted runners and 13 less-conditioned individuals. throughout the entire experiment. All subjects were exposed to a standard Equilibrium changes which were observed on medical evaluation protocol, which consisted the first day of centrifuging regressed and the of a gradual-onset (0.1 G/s) acceleration post-test function did not essentially differ exposure (GOR 1), followed by a series of from the initial level. The experimental rapid-onset ( 1.0 G/s) acceleration exposures results give evidence that inertial forces can (ROR), a second gradual-onset rate exposure be used to lessen the unfavorable effects of (GOR2), and a third gradual-onset rate hypokinesia. exposure with the subjects performing anti-G straining maneuvers (GORS). Aerobic 19. Georgiyevskiy VS, VM conditioning was not found to be associated Mikhaylov. with a reduced heart rate response to +Gz Effect of hypokinesia on human stress, compared to the response of circulation. undconditioned subjects, when the following Kosmicheskaya Biologiya i variables were considered: heart rate change Meditsina 2:48-51, 1968. from rest to maximum exposure heart rate, Authors' Abstract heart rate change from rest to the heart rate The combined effect of bedrest and achieved at the onset of maximum G, and the accelerations on human circulation was rate of change in heart rate per unit +Gz. studied using mechano- and poly- Although enhanced parasympathetic tone, cardiographic techniques. The experiments induced by long-term aerobic conditioning were conducted on young healthy male test (running) results in a reduced heart rate at subjects. The experiments demonstrated an rest and during +Gz stress, it does not alter increase in heart rate and average blood the responsiveness of the heart rate to +Gz pressure, a decrease in the ejection period and stress. development of orthostatic hypotension. Variations in some hemodynamic indices 18. Gale RR, VV Usachev, LN indicated a phasic pattern reaching a Gavrilova, LG Yelkina, PA maximum on the 32-42nd day. Yelkin, IS Krikum, VG Ovechkin, BV Ustyushin. 20. Gogolev KI. and PV, and inversely related to prior athletic Correction of transcapillary exchange conditioning level and height. Since in man under the influence of rotation individuals in this age group are more on a centrifuge while immersed in susceptible to cardiac and cerebrovascular water. sequelae following orthostatic hypotension, Kosmicheskaya Biologiya i use of the anti-G suit is strongly indicated Aviakosmicheskaya Meditsina during Shuttle re-entry, especially in highly 13:72-74, 1979. aerobically conditioned individuals. Author's Abstract Acceleration of +Gz induces both 22. Goldwater D J, VA Convertino. intravascular redistribution of fluid and +3Gz tolerance in aerobically-trained shifting thereof from plasma to the and sedentary men after shuttle flight perivascular space, and leads to a change in simulation. hydrocolloid balance of blood and the Aviation, Space, and Environmental interstitial medium in man. Such Medicine 59:485, 1988. disturbances could be the cause of changes in Authors' Abstract transcapillary exchange of fluid and proteins, Thirteen men giving a history of regular the adequacy of which is determined by the aerobic training (AT) ( VO 2 max 47.4 + 1.6 functional state of mechanisms responsible ml/kg.min) were compared to 8 age-matched for redistribution thereof in the case of (35 to 50 y.o) sedentary controls (S) ( '_'O 2 sudden increase in gravity and in the max 35.2 + 1.5) to assess +Gz tolerance aftereffect period. In this work, we submit the results of (GTOL) analogous to, although more intense testing the reactions of the system of than, Shuttle re-entry stress. Subjects went hydrocolloid equilibrium in man to to greyout at +3 Gz pre-and post-6 days of head-down (-6 °) bedrest (BR). PreBR acceleration of 3 units +Gz after 3-day GTOL for AT was 372 sec vs 537 for S (ns). immersion, combined or not with period PostBR decrease in GTOL was different rotation on a small-radius centrifuge. (p<.05) for AT: -259 sec (-68%, p<.01) vs 21. Goldwater D J, VA Convertino, H S: -165 sec (-35%, ns). PreBR resting (R) Sandier. heart rates (HR) were lower (p<.05) in AT Acceleration tolerance in 55 to 65 year (63bpm) than S (72). PostBR, resting HR of old men after shuttle flight simulation. AT increased 13% (p<.01); S HR's were unchanged. PreBR HR increase from R to Aerospace Medical Associated peak 3 G was much larger (p<.05) in AT Preprints, 1981. p. 179-180. (+90%, P<.01) than in S (+63%, p<.01). (Abstract). After BR, 3 Gz increased HR similarly (mean Authors' Abstract +85%, p<.01) in both groups. Resting Healthy 55 to 65 y.o. men tolerated diastolic pressures (DBP) were lower Shuttle re-entry acceleration before and after (p<.05) in AT (54 mmHg) than S (63) preBR BR as well as subjects 35 to 55 years old. as well as postBR, whereas systolic BPs Although the G-suit improved postBR were similar in both groups. After BR, tolerance at all stress levels, it was deconditioned AT had + 3 Gz HR and BP significantly more efficacious for older men responses, from rest to peak 3G, similar to during postBR 3 Gz than for men a decade S. Nevertheless, the decrease in GTOL younger. These results suggest an important postBR was larger in AT. PreBR plasma role for increased central blood volume in volume (PV, ml/kg) was inversely correlated restoring postBR acceleration tolerance for with BR GTOL (r = -.64, p<.01). BR older subjects. Pre BR "_/O2 max, PV, decreases in PV were correlated with low BR estimated TBV, and height were significant GTOL (r = .63, p<.01) and with preBR independent predictors of postBR 3-Gz VO 2 max ( r = .42, p<.05). Aerobic tolerance in these subjects. Bedrest-induced training may be associated with greater +Gz decrease in 3 Gz acceleration tolerance was intolerance in spaceflight participants after directly proportional to the decrease of BV

8, weightlessnessexposurein theabsenceof groups: an exercise (heat) group, ambient countermeasures. temperature (T a) 40.6°C, relative humidity (rh) 42%, and a peak 90 2 of 52%; an 23. Golovkina OL. exercise (cool) group, T a = 18.7°C, rh = Extemal respiration and gas exchange 48%, and "v'O2 peak = 55%; and a sedentary reactions to exercise during rotation control (cool) group. There was no change of man on a short-radius centrifuge. in peak ventilation, peak heart rate (HR), Kosmicheskaya Biologiya i Aviakosmicheskaya Meditsina peak VO 2, or in resting PV in any group 13:58-60, 1979. after training. Heart rate and T_, were Author's Abstract significantly lower after training in both cool Periodic rotation on a short-radius and hot environments; HR by 17 b ' min _ centrifuge (SRC) combined with physical (p<0.05) and 27 b" min _ (12<0.05), exercise is one method of preventing respectively, and Tr_ by 0.4uC (p<0.05) and functional disturbances of physiological 0.4°C (p<0.05), respectively. Sweat rates systems, which occur under the influence of were not different in any group. In all weightlessness. However, there has still groups, acceleration tolerances were not been very inadequate study of the reactions of different after training; they ranged from 3.5 the main physiological systems of the body to to 3.8 G (373-410 s). The loss (shift) in PV rotation on an SRC combined with exercise. during acceleration ranged from -5.8% to - Our objective here was to study the 10.3% (nonsignificant). With the exception reactions of the system of external respiration of the significant reductions in HR and T_, and exchange of gases to rotations on an 8 d of moderately heavy physical training at SRC ( R = 2 m) combined with exercise on a 52-55% of peak oxygen uptake in cool or hot environments had no effect on slow-onset bicycle ergometer (BE) during prolonged +Gz acceleration tolerance in women. These immersion. Since the system of external respiration is functionally closely related to findings may be of relevance for astronauts in the circulatory system, we considered the training. possibility of using the parameters of external respiration to evaluate endurance for these 25. Greenleaf JE, PJ Brock, D factors. Sciaraffa, A Polese, R. Elizondo. 24. Greenleaf JE, PJ Brock, D Effects of exercise-heat acclimation Sciaraffa. on fluid, electrolyte, and endocrine Effect of physical training in cool and responses during tilt and +Gz hot environments on +Gz acceleration acceleration in women and men. tolerance in women. Aviation, Space, and Environmental Aviation, Space, and Environmental Medicine 56:683-689, 1985. Medicine 56:9-14, 1985. Authors' Abstract Authors' Abstract Plasma fluid, electrolyte, protein, renin, Rectal temperature (Tr,), sweat rate, and vasoactive hormone (epinephrine, plasma volume (PV), peak oxygen uptake norepinephrine, vasopressin) responses were measured in six women (21-23 yr) and four (peak "{/0 2 ), and relaxed +Gz acceleration men (21-38 yr) before and immediately tolerance (0.5 G min _ linear to grayout) following an orthostatic tolerance test (700 were measured in 15 healthy women 21-41 head-up tilt) and a +Gz (head-to-foot) years old before and after submaximal acceleration tolerance test (0.5 G ' min isotonic exercise training for 2 h ° d _ on a linear ramp to grayout). These tests were cycle ergometer. The women had 2 weeks of conducted before and after 12 consecutive acceleration runs and 'v'O 2 testing, followed days of exercise-heat acclimation when the by 8 d of exercise training, post-training subjects exercised on a cycle ergometer at a acceleration runs on day 9, and peak VO 2 relative oxygen uptake of 44% to 49% peak tests on day 10. They were divided into three oxygen uptake in a hot environment (T_ = 40°C,42%rh). During acclimationplasma separated by a 2 l-d recovery period) and then volumeincreasedby 10.6%(p<0.05)in the a final week of recovery. During the womenandby 11.9%(p<0.05)in themen; ambulatory periods, the subjects exercised on in bothgroupsexerciseheartratedecreased a bicycle ergometer at 50% of their maximal significantly. After acclimation,acceleration oxygen uptake (max "_/O2 ) for 1 h/d. During tolerancewasunchangedin bothgroups two of the three bedrest periods, the subjects (range3.I to 3.4G); thewomen'stilt performed in the supine position one of two tolerancewasunchanged(range33.6to 39.5 routines, either isometric exercise (21% of min),but themen'stilt toleranceincreased max leg extension force for 1 min followed from 30.4min beforeto 58.3min (A =91%, by l-min rest) or isotonic exercise (68% of p<0.05)afteracclimation.Sincethepattern max _,'O 2 ) for 0.5 h in the morning and of fluid, electrolyte,andproteinshiftsand accelerationtolerancesin thewomenandmen afternoon. During the third bedrest period, werevirtually thesame,thehormone no exercise was performed. In general, +Gz responseswerehighly variable,andthe tolerance was reduced by 24% to 35% men'stilt toleranceincreasedsignificantly p < 0.05) after bedrest. Compared with afteracclimation,it isclearthatresponsesto control values, there were significant reductions in average tolerance times after tilting cannotbe usedto predictresponsesto bedrest with no exercise and isotonic exercise acceleration.Analysisof datafrom the at all G levels. With isometric exercise, there presentstudyandtheliteraturesuggeststhat currentexercisetrainingregimesshouldbe was a significant decrease in tolerance at 2.1 unrestrictedfor astronautswhohavenot Gz but not at 3.2 Gz or 3.8 Gz, even though previouslybeenhighly endurancetrained. the latter tolerances were reduced by 15.6% Until provenotherwise,careshouldbetaken and by 10.0%, respectively. Both exercise regimens maintained tolerance at levels equal in theselectionof astronautsandin thetype to or above that obtained with no exercise. andintensityof theexercisetraining programsengagedin by thosewhohavebeen Compared with control values, average or arehighly endurance-trainedathletes. tolerances were lower (p < 0.05) after the two recovery periods between the bedrest periods (-24% to -26% at 3.2 Gz and 3.8 26. Greenleaf JE, RF Haines, EM Gz), indicating that 3 weeks of ambulation Bernauer, JT Morse, H was not sufficient time for full recovery from Sandier, R Armbruster, L the deconditioning induced in this study. A Sagan, W van Beaumont. prediction equation was constructed with data +Gz tolerance in man after 14-day from all comparable studies utilizing bedrest periods with isometric and deconditioned men riding relaxed without isotonic exercise conditioning. protective garments: Tolerance (in seconds) = Aviation, Space, and Environmental -334 + (1715/+Gz level). From this Medicine 46:671-678, 1975. equation, the calculated tolerance after bedrest Authors' Abstract is 13.5 min at 1.5 G, and the point of zero The purpose of this study was to tolerance is 5.1 Gz. determine the effects of isometric or isotonic exercise training on post-bedrest +Gz 27. Greenleaf JE, HO Stinnett, GL tolerance. Seven male volunteers, 19-22 Davis, J Kollias, EM Bernauer. years, underwent accelerations of +2.1 Gz Fluid and electrolyte shifts in women (740s), +3Gz (327s), and +3.8 Gz (312s) in during +Gz acceleration after 15 a selected, randomized order; the ramp to days' bed rest. peak acceleration was 1.8 G/min. The Journal of Applied Physiology centrifugation runs were terminated by loss 42:67-73, 1977. of central vision (blackout) to a white light Authors' Abstract with a luminance of 3.15 x 10.5 log Twelve women (23-34 yr), comprising a candle/cm 2 (0.092 ft-lambert). The study bed-rest (BR) group of eight subjects and an began with a 14-d ambulatory control period, ambulatory (AMB) group of four subjects, followed by three 14-d bedrest periods (each were centrifuged after 14 days of ambulatory

10 control(C), after 15daysof a 17-dayBR a luminance of 1.2 x 10-2 candles/cm (35.3 period,andon thethird dayof recovery(R). foot-lamberts). The experimental design Venousbloodwastakenbeforeandafterthe consisted of a 3-week ambulatory control third +3.0G accelerationrun (1.8G/min). period (C), 2 weeks of bed rest (BR1), Relativeto (C),the+Gz toleranceafterBR followed by a 2-week ambulatory recovery wasreducedby 49.0%(P<0.05)in theBR period (R), then 2 weeks of bed rest with groupandby 38.7%(NS)in theAMB rehydration prior to centrifugation (BR2) and group;during (R)theBR groupregainedup a final week of recovery. +Gz tolerance was to 89.4%andtheAMB groupup to 87.1%of measured immediately before and at the end their (C) tolerances.In eachof thethreetest of each bed rest period. The subjects ate a periods,theshiftsin plasmaNa,C1,PO 4, calorically controlled, nutritionally balanced and osmotic contents, which accompanied diet and exercised _ hr each day on a bicycle +Gz, followed the outward shift of plasma ergometer at 50% of their maximal oxygen volume (PV). The correlation of the shift of uptake (approx. 450 kcal/day) during the PV during acceleration with the +Gz entire study. The subjects were rehydrated tolerance was 0.72 (P<0.01). During with 1.0 to 1.9 liters of a drink, containing acceleration, the PV and electrolyte loss for 143 mEq/1 Na, 31 mEq/l K and a total both groups after BR was about half the loss osmolarity of 620 mOsm/l, given over a 3- of (C) and (R). Compared with (C) and (R) hour period before centrifugation in BR2. values, potassium shifts were variable but the There were significant (p<0.05) mean corpuscular volume and mean reductions in average +Gz tolerances corpuscular Hb contents and concentrations following both bed rest periods at all three G- were unchanged during all +Gz runs. The levels. Compared with control values, results indicate that: 1) the higher the (C) +Gz following BRI, average ramp plus plateau tolerance, the greater the tolerance decline due tolerances decreased 36% at 2.1 G, 30% at to BR; 2) relative confinement and reduced 3.2 G and 44% at 3.8 G. Compared with activity contribute as much to the reduction in recovery values, following BR2, average tolerance as does the horizontal body position tolerances decreased 23% at 2.1 G, 29% at during BR; 3) bed-rest deconditioning has no 3.2 G and 34% at 3.8 G. Rehydration effect on the erythrocyte volume during +3.0 increased tolerance (p<0.001) only at 2.1 G, Gz; and 4) about one-half the loss in but tolerance was not completely restored to tolerance after BR can be attributed to PV and control values. Compared with control electrolyte shifts. values, average tolerances at all three G- levels were lower after the recovery period, 28. Greenleaf JE, W van Beaumont, suggesting that 2 weeks of recovery is not EM Bernauer, RF Haines, H long enough to permit tolerance to return to Sandier, RW Staley, HL pre-bed rest levels. After bed rest the time Young, JW Yusken. full visual capability can be maintained at Effects of rehydration on +Gz plateau during these acceleration profiles can tolerance after 14-days' bed rest. be estimated from the equation: Tolerance Aerospace Medicine 44:715-722, (sec) = 345 + (1605/G-level). In relaxed, 1973. deconditioned men without protective Authors' Abstract garments, tolerance at 2.0 G is 7.6 min and To determine if rehydration increases the level of instant blackout is about 4.7 G. +Gz tolerance following bed rest It is concluded that 2 weeks of bed rest deconditioning, eight male volunteers (21-23 results in a significant decrease in yrs) were subjected to acceleration levels of centrifugation to tolerance which occurred 2. I G (740 sec), 3.2 G (327 sec) and 3.8 G despite the use of moderate daily isotonic (312 sec) presented in random order; the rate exercise. Compared to nonhydration control of acceleration was 1.8 G/min. Acceleration values, rehydration significantly improves tolerance was determined by either loss of +Gz tolerance only at 2.1 G but did not peripheral vision (greyout) or by loss of return tolerance to ambulatory control levels. central vision (blackout) to a white light with

II 29. Grigoriev AI. In: Physiological Effects of Correction of changes in fluid- Prolonged Positive +Gz electrolyte metabolism in manned Acceleration following One and space flights. Seven Days Bedrest, edited by WH Aviation, Space, and Environmental Shumate. Houston, TX: NASA Medicine 54:318-323, 1983. Manned Spacecraft Center, Chapt. 6, Author's Abstract 1971. p.111-124. In order to prevent and correct Authors' Abstract hypohydration and negative electrolyte 1. Lower body negative pressure (LBNP) balance, the effects of exercises, lower body was used as a cardiovascular stressor to negative pressure (LBNP) and water-salt measure orthostatic tolerance in 9 subjects supplements (WSS) were investigated in who underwent one and seven day bed rest more than 100 test subjects durin_g 14-, 49- periods. and 182-d headdown tilt tests (-4"). A 2. Accelerative (centrifuge) +Gz tolerance combined use of WSS and LBNP during testing preceded all LBNP tests except a final regular exercises led to a distinct water and series run expressly to assess the possible sodium retention. These changes were effect of centrifugation upon LBNP mainly determined by the stimulation of the responses. No correlation between the two renin-angiotensin-aldosterone and antidiuretic was found. systems. After these countermeasures were 3. Orthostatic tolerance by LBNP testing tested in simulation studies, they were used was decreased after both bed rest periods. by 12 cosmonauts during the 63- and 185-d The magnitude and extent of decrease was space flights. The detailed analysis of the greater after the 7-day period of bed rest. postflight examinations of the crewmembers This was best determined by elevations of suggests that these countermeasures may heart rate and decreases in stroke volume. exert a beneficial effect on fluid-electrolyte Resting mean pulse pressure was modestly balance. decreased, while change in leg size tended to be variable and resting cardiac output was 30. Grigor'yev AI, YeB unaltered. Three incidents of presyncope Shul'zhenko. occurred during tests after bed rest. Effects of minimal gravitational loads 4. Physiologic results from LBNP tests on fluid-electrolyte metabolism and closely parallel those of other orthostatic tests renal function of man during and may be used as an auxiliary test for prolonged immersion. predicting human tolerance to reentry forces. Kosmicheskaya Biologiya i Aviakosmicheskaya Meditsina 32. Houghton JO, DK McBride, K 13:27-31, 1979. Hannah. Authors' Abstract Performance and physiological effects It was demonstrated that renal excretion of acceleration-induced (+Gz) loss of of fluid osmotically active substances and consciousness. electrolytes could be reduced, using low Aviation, Space, and Environmental gravitational exposures (+Gz). The degree Medicine 56:956-965, 1985. and duration of water and electrolyte retention Authors' Abstract were different with respect to the Loss of consciousness (LOC) was experimental time. The major physiological intentionally induced by exposing eight mechanisms of the changes in fluid- volunteers to individually-titrated levels of electrolyte metabolism were a decrease in the head-to-foot acceleration (+Gz) using 2- and glomerular filtration rate and a change in 4-s onset rates (mean = 6.1 +Gz required to water and ion transport in renal tubules. induce LOC) and a gradual, 0.067 G • s onset rate (mean = 7.2 Gz required). 31. Hoffler GW, RA Wolthuis, RL Subjects were trained over a prior 2-week Johnson. period on a multitask battery comprising three Lower body negative pressure. simultaneously executed tasks representative

12 of those required in piloting, and then possible +Gz acceleration profiles anticipated centrifuged to LOC at each of the three onset for space shuttle vehicle travel. All subjects rates on alternate days. Performance was demonstrated decreased +Gz tolerance assessed for 5 min prior and 7 min after each following simulated weightlessness. While LOC. Primary results indicated: a) only one of six subjects could not tolerate the significant and substantial impairment in the +Gz profile in the control phase of the study, two discrete response secondary tasks three of the six could not complete the (choice reaction time and arithmetic postbed-rest study. The use of an inflated computation), with mean recovery to pre- standard Air Force cutaway G-suit improved LOC levels within 3 min on each task, b) no +Gz tolerance in all subjects, but two of six group mean impairment for the primary, subjects still failed to complete the profile. compensatory tracking task, c) substantial These findings are discussed in reference to individual variation in physiologically and the selection of untrained humans for space behaviorally defined recovery from LOC, d) shuttle vehicle travel. a negative influence of aerobic fitness on G tolerance and LOC recoverability, and e) that 34. Kakurin LI. recovery effects were not generally dependent Effect of long-term hypokinesia on upon onset rate. Mean absolute the human body and the hypokinetic incapacitation (head dropped) for the rapid component of weightlessness. onset rates was 12.1 s. For the gradual onset Kosmicheskaya Biologiya i rate, mean absolute incapacitation was 16.6 Meditsina 2:59-63, 1968. s. Mean relative incapacitation (head erect, Author's Abstract no voluntary task engagement) for the rapid An experimentally diminished muscular onset rates was 11.6 s; for the gradual onset activity of man can be used as a model to rates, mean relative incapacitation was 15.7 reproduce some human reactions similar to s. Evidence for retrograde anmesia effects those induced by weightlessness. The was equivocal. purpose of the 62-day experiment was to study adaptive processes of the human body 33. Jacobson LB, KH Hyatt, H and to establish the efficiency of physical Sandier. exercises during hypokinesia. Detailed Effects of simulated weightlessness clinical and physiological examinations on responses of untrained men to revealed disturbances in the functioning of +Gz acceleration. the circulatory, respiratory and Journal of Applied Physiology neuromuscular systems, changes in natural 36:745-752, 1974. immunity and diuretic deterioration. Physical Authors' Abstract exercises with a load up to 1,000-1,200 Space shuttle vehicle travel will expose Cal/day produced a limited positive effect. crew and untrained lay personnel to headward-acting (+Gz) acceleration stresses 35. Kakurin LI, RM Akhrem- which may be as high as 4 G following Akhremovieh, YuV periods of weightlessness. Previous studies, Vanyushina, RA Varbaronov, using bed rest as an analog of VS Georgiyevskiy, BS weightlessness, demonstrated the orthostatic Katkovskiy, AR Kotovskaya, intolerance and even syncope which occurs NM Mukharlyamov, NYe on reexposure to a +lGz environment (700 Panferova, YuT Pushkar, YuA passive tilt) following periods of simulated Senkevich, SF Simpura, MA weightlessness, suggesting that postbed-rest Cherepakhin, PG Shamrov. exposure to still higher +Gz acceleration The influence of restricted muscular stresses would exaggerate the undesirable activity on man's endurance of responses. This study documents bedrest physical stress, accelerations and induced metabolic and physiologic changes in orthostatics. six untrained men exposed, following a 2-wk Soviet Conference on Space Biology period of simulated weightlessness, to and Medicine 1996. p. 110-117.

13 Authors' Abstract methods of normalization of physiological For the past few years the attention of reactions after a protracted stay by man in the Soviet and foreign researchers has been conditions mentioned has great significance. drawn to investigation of man's condition The study of the reactions of external when his muscular activity is restricted breathing during "head-pelvis" overloading (hypokinesia). The added interest in this (+gz) by a three-unit amount after a 13-day problem is due to the fact that many of man' s stay by man in water immersion, and in contemporary professions are associated with immersion which was combined with restricted muscular activity. This problem is "conditioning" gravitational effects, acquiring a prominent place in astronautics comprised the task of the present since prolonged manned space flights have investigation. now become a reality. The investigation has been conducted Weightlessness and the small volume of with the participation of two groups of the spacecraft cabin place man's locomotor healthy men of ages 24-36 yr. The test apparatus under unusual functioning subjects of the first group (5 men) were conditions. The works of Kraus and Raab situated in immersion without additional (1961), Taylor et al. (1949), Dcitrick et al. effects ("pure" immersion); the test subjects (1949), Graveline et al. (1961, 1964), of the second group (5 men), starting from Beckman et al. (1961) as well as of the the 6 _ day of immersion, were subjected groups headed by A.V. Korohkov, L.I. daily to a single effect of "head-pelvis" Kakurin, A.A. Demidov and other overloads of up to two units in amount and researchers have demonstrated that with up to 1.5 h in duration. prolonged restriction of movements, man Before and after immersion, the test develops functional disorders of the subjects of both groups were subjected to locomotor apparatus, circulatory system, three units of overloading for 300 sec. neuro-endocrine system and higher nervous External breathing was investigated by the activity. At the present time these Douglas-Holdern and pneumotachography polymorphous disorders are combined into methods. We recorded and calculated the the syndrome of hypokinetic disease. following indices: breathing frequency (BF), As applied to the problems of space respiratory volume (RV), momentary medicine, hypokinesia should be investigated respiratory volume (MRV), volume flow rate from two aspects. First, investigation of of air (intensity) at the intake (W,), the physiological reactions in long experiments at duration in inhalation (T_), the coefficients of Earth's gravitation, and the second- variation of BF, RV, and T_ (CV), oxygen prophylaxis of hypokJnetic disorders that consumption ( _/O 2 ), and the coefficient of could arise in a low gravitation field and oxygen use (CUO2). during weightlessness in space flights. It is The gas-exchange data have been especially important to investigate the limits presented in the STPD system, and the data of endurance of acceleration, orthostatic of ventilation and the biomechanics of factors and physical stress during re-entry to breathing in the BTPS system. The results Earth. have been processed statistically by a difference method. 36. Kamenskii YuN, EB Shui'zhenko. 37. Kamenskiy YuN, YeB Prophylaxis for disturbances of Shul'zhenko, VG Andreyeva. external breathing in immersion. Effect of systematic exposures to Kosmicheskie Issledovaniya gravity on the external respiration 14:474-476, 1976. function during prolonged Authors' Abstracts immersion. A protracted stay by man in Kosmicheskaya Biologiya i weightlessness or in conditions which Aviakosmicheskaya Meditsina simulate it is accompanied by a reduction of 10:40-45, 1976. gravitational stability. Therefore, a search for Authors' Abstract

14 Test subjects were exposed to 13-day plasma arginine vasopressin (AVP) levels immersion alone or combined with were reduced by 33%. Plasma renin activity centrifuging. The immersion did not (PRA) increased by 91% (P<0.05) above influence the state of ventilation and gas ambulatory control values from days 10 exchange at rest, but significantly diminished though 15 of bed rest. When compared to the functional capabilities of external precentrifuge values, exposure to +3 Gz prior respiration. An exposure of the test subjects to bed rest provoked a 20-fold rise (P<0.05) to acceleration during the second half of in mean plasma AVP but resulted in only a water immersion resulted in the normalization slight increase in PRA. After bed rest, of the functional reserves of external acceleration increased plasma AVP 7-fold respiration. This may be a consequence of an (P<0.02); however, the magnitude of this increase in overall physical tone of the body. increase was less than the post +3 Gz value obtained prior to bed rest. After bed rest, no 38. Katkovskiy BS. significant rise was noted in PRA following Human basal metabolism during +3 Gz. This study demonstrates that prolonged bedrest. prolonged bed rest leads to a significant rise Kosmicheskaya Biologiya i in the PRA of female subjects, while Meditsina 1:67-71, 1967. exposure to +Gz acceleration provokes a Author's Abstract marked rise in plasma AVP. 1. The metabolic rate and pulmonary function of healthy test subjects were studied 40. Khapilov NV, VS Panchenko, during 20- and 62- day bedrest experiments, NN Kotov, BF Asyamolov. before and after which they were subjected to Effect of hypokinesia and +Gz accelerations. accelerations on transport function of 2. Three subjects who performed no human blood. physical exercises during the 62-day bedrest Kosmicheskaya Biologiya i revealed a decreased metabolic rate and Aviakosmicheskaya Meditsina virtually unaltered pulmonary function. 19:31-33, 1985. 3. Three test subjects who performed Authors' Abstract physical exercises during the experiments The results of 44 studies of circulation also manifested a reduction of oxygen parameters and blood transport function of 14 consumption and metabolic rate beginning test subjects exposed to 7-day bed rest with the third 10-day period. (-10 ° head-down tilt) and acceleration of 4.5 4. It appears very probable that the latter Gz have demonstrated that the blood is unrelated to hypokinesia but is due to an transport carriers and their actively binding increased physical conditioning or to centers form working structures in the adaptation to a changed hydrostatic pressure adaptive reactions. As compared to the of body fluids. pretest level, the distribution ratio of '4C- adenine between two immiscible phases 39. Keil LC, S Ellis. (plasma/oil, erythrocytes/oil) varies from - 12 Plasma vasopressin and renin activity to 14% on bed rest day 3 to +32 to 40% on in women exposed to bed rest and bed rest day 7; it increases by 145-150% after +Gz acceleration. exposure to +4.5 Gz acceleration. The Journal of Applied Physiology parameters of the blood transport function 40:911-914, 1976. give a quantitative description of its adaptive Authors' Abstract reactions to environmental effects. To study the effect of prolonged recumbency on plasma vasopressin and renin 41. Khudyakova MA, YeB activity, eight women (23-34 yr) were Shul'zhenko. subjected to 17 days of absolute bed rest. Blood clotting function during 12-day The +3 Gz tolerance of the subjects was immersion in water, and the tested before and after 14 days of bed rest. preventive role of revolving on a From day 2 and through day 17 of bed rest, centrifuge.

15 Kosmicheskaya Biologiya i dependence on stature and physical A viakosmicheskaya Meditsina fitness). 3:79-81, 1977. International Zeitschrift fiir Authors' Abstract Angewandte Physiologie There is a sparse literature dealing with einschliesslich Arbeitsphysiologie hemostasis in the presence of hypodynamia. 26:205-226, 1968. Ye. I Chazov and V.G. Ananchenko failed to Authors' Abstract demonstrate changes in 3 out of 4 subjects Experimental studies in a group of 12 during 3-day hypodynamia, while one highly trained athletes ( 40 2 max: 4.6 1/min) presented increased anticoagulant and lytic properties of blood. In the case of 20-day and a group of 12 untrained students ('v'O 2 hypodynamia, the same authors found max: 3.4 l/min) lead to the following results: increased fibrinolytic activity of plasma and 1. During a 20 rain tilt (90°), which included higher blood heparin content, as well as two additional respiratory maneuvers, the lower heparin tolerance of plasma in the 4 number of faints and the average subjects. cardiovascular responses did not differ According to the report of L.M. Filatova significantly between the groups, except for a and O.D. Anashkin, an increased lower heart rate level in athletes; 2. During linear increase of acceleration with a rate of thrombogenic potential of blood was observed on the 8 thday of bedrest in the 1G/15 sec, the average +Gz-tolerance horizontal position. Thereafter, a decrease in (blackout level) was almost identical in both coagulating potential of blood was observed groups being 6.9 for the athletes and 6.8 for in the case of 64-day hypodynamia. the students; 3. Statistically significant The results of Ye. I Dorokhova, which coefficients of the product-moment correlation were calculated in the total of both were obtained with 70-day hypodynamia, revealed that there was a hypocoagulation groups for the interrelation of the following reaction toward the end of the first 2 weeks. variables: a) +Gz tolerance and arterial blood As the period of hypodynamia increased the pressure at rest (r = +0.48 to +0.55), b) hemophilic reaction also increased in all +Gz-tolerance and heart-eye distance (r = subjects. -0.41), and c) total body length and V.A. Isabayeva and T.A. Ponomareva responses of mean arterial pressure to tilt (in failed to observe an increase in thrombogenic fainters: r = -0.11, in non-fainters: r = properties of blood during 10-day +0.47); 4. The coefficient of multiple hypodynamia after adaptation to high altitude. determination computed for the dependence Longer periods of hypodynamia (24 days) of +Gz-tolerance on heart-eye distance and diminished coagulant properties. systolic blood pressure at rest (r2_ 23= 0.492) Our objective here was to study the allows the explanation of almost 50% of the changes in various indices of hemostasis variation of +Gz-tolerance, instead of 16%, during 12-day immersion in water and to respectively 23%, if the two independent determine whether it is possible to use variables are used singly; 5. The maximal increased gravitation for prevention of oxygen uptake showed the expected "decondition" of the organism during significant correlation to the heart rate at rest immersion. (r = -0.68), but not to the acceleration- tolerance or to the cardiovascular responses 42. Klein KE, F Backhausen, H to tilting. Briiner, J Eichhorn, D Jovy, J 43. See number 42. Schotte, L Vogt, HM Wegmann. Die Abh_ingigkeit der Orthostase- und Beschleunigungs- toleranz von K/Srperbau und Leistungsf'zihigkeit. (The relation between tilt table and acceleration-tolerance and their

16 44. Klein KH, H Br0ner, J Eichhorn, Aerospace Medicine 40:293-297, KL Schalk_iuser, J Schotte, ED 1969. Voigt, HM Wegmann. Authors' Abstract Vergleichende Untersuchungen de A comparison of 12 healthy, but kt_rperlichen Leistungf'_ihigkeit des physically untrained, students with 12 highly Menschen bei Muskelarbeit, im trained athletes proved significant differences Sauerstoffmangel und bei for the maximal working capacity ( 'v'O 2 max Beschleunigung. (Evaluation of in students: 43.9 ml/kg/min, in athletes: 64.9 physical fitness for exercise and ml/kg/min). As further indication for the big tolerances for hypoxia and differences in "physical fitness", the heart acceleration). rate level of athletes was about 22 percent International Zeitschrift fiir lower at rest and during a 900 tilt of 20 min. Angewandte Physiologie duration. However, "orthostatic tolerance," einschliesslich Arbeitsphysiologie i.e., the number of fainters and the responses 22:190-206, 1966. of blood and pulse pressure to tilt in non- Authors' abstract fainters, was almost identical in both groups. Physical fitness for exercise and The same was true for "acceleration tolerances to hypoxia (287 mmHg) and tolerance;" i.e., the central light loss during acceleration (+Gz) were evaluated in 20 an acceleration, increasing linearly with a rate healthy male students (21-28 years), which of 1G/15sec. (in students: 6.8 +Gz, in were physically untrained and not adapted to athletes: 6.9 +Gz). In the total of both unusual environments. A very close groups, statistically significant coefficients of correlation (r = +0.78) was found for the true the product-moment correlation could be maximal oxygen uptake ( "QO2 max) and the computed for the interrelation of the aerobic capacity estimated from the heart rate following variables: body height and the during submaximal exercise using the responses of arterial pressure to tilt (for mean Astrand nomogram. From some step tests pressure in non-fainters: r -- +0.47, for pulse only the Harvard index showed a moderate pressure in fainters: r = -0.56); +Gz tolerance and arterial pressure at rest (r = +0.48 to correlation (r = -0.35) to the "QO 2 max. The +0.55); +Gz tolerance and heart-eye distance "_'O 2 max was nearly independent from (r = -0.41). The coefficient of the "multiple hypoxia and acceleration tolerances, whereas correlation" computed for the dependance of the results of the step tests uniformly revealed the +Gz tolerance on systolic blood pressure negative dependances (r = -0.41 to -0.64) on at rest and on heart-eye distance was R_23 = the stress tolerances with the one exception of 0.70. By means of the corresponding the Schneider index, which correlated equation of the multiple regression, a diagram positively (r = 0.41) with the acceleration for prediction of central light loss during tolerance. Negative correlations (r = -0.46 to acceleration from the knowledge of the two -0.60) were also computed between the independent variables was constructed; the different criteria for hypoxia and acceleration "standard error of estimate" was 0.56 +Gz. tolerance. "Physical efficiency" proved to be an inhomogeneous characteristic, which 46. Klein KE, H Briiner, ED Voigt, cannot be predestinated by "fitness" tests HM Wegmann. under exercise alone, but has to be evaluated Comparative studies on physiological by a test-battery combined in regard to each indices of fitness in man under specific task. exercise, low pressure, and acceleration. 45. Klein KE, H Briiner, D Jovy, L In: Human Adaptability and it's Vogt, HM Wegmann. Methodology, edited by H Influence of stature and physical Yoshimura, JS Weiner. Tokyo: fitness on tilt-table and acceleration Japanese Society for the Promotion tolerance. of Science, 1966. p. 234-247. Authors' Abstract

17 In 20 malestudentsof oneagegroup, correlation between heart rate responses to whichwerehealthyanduntrained,andnever the different stressors and the corresponding hadbeenadaptedto unusualenvironment, tolerances proved negligible relationships physicalfitnessandtolerancesto low only; whereas heart rates were always highly pressureandaccelerationweremeasured,and dependent on sea level "¢O 2 max (r = -0.61 thecoefficientsof correlationbetweenthe to -0.83). The results do not support the idea resultscalculated.Thepredictionof _'O2 of an improvement of human tolerance to max.with Astrand's procedureshoweda environmental extremes by physical exercise verycloserelationshipto thetrueaerobic training. working capacity(r = 0.78),while from all steptests,only theHarvardmethod 48. Klein KE, HM Wegmann, P correlatedmoderatelyto thesameindex Kuklinski. (r = 0.35). The true VO2 max.was Athletic endurance training-advantage absolutelyindependentof theresistanceeither for space flight?: The significance of to hypoxia,or to hypergravity,butthe physical fitness for selection and "cardiovascularfitness"measuredby step training of Spacelab crews. testsshowedmoderateto highdependency Aviation, Space, and Environmental on them(r = 0.41-0.64),whichwasnegative Medicine 48:215-222, 1977. in all cases,exceptfor therelationbetween Authors' Abstract the"Schneider"testandthetoleranceto While intensive physical exercise has gravitationalforces,thelastbeinglikely, been part of the conditioning of astronauts becauseof theorthostaticresponsein the and cosmonauts for spaceflights, its benefits Schneiderscore.Theinterrelationbetween have been questioned. After reviewing the thetwo stresstoleranceswasalsonegative(r pertinent literature, it is concluded that the = -0.46to -0.60). Physicalfitness,as morphological and functional changes determinedby thedifferentmethods,isnota obtained with athletic endurance training are homogeneousqualityof thebody. The rather specific and of no general advantage knowledgeof theinterrelationsatthesame for the tolerance to space stresses. timerestrictsandextendsthemeaning, Particularly during gravitational loads, in the significanceandpracticalvalueof theindices. relaxed subject, these changes allow a more pronounced shift of fluid into the lower 47. Klein KE, HM Wegmann, H extremities, with the possible consequence of Briiner, L Vogt. a reduced tolerance. This unfavourable Physical fitness and tolerances to response, obviously, is accentuated through environmental extremes. immersion and weightlessness. The aerobic Aerospace Medicine 40:998-1001, work capacity is also more impaired in 1969. athletes. Based on these conclusions, Authors' Abstract recommendations for crews and passengers During "submaximum" loading tests of of future Spacelab missions are given with 20-30 min duration at simulated altitude (312 respect to selection and pre- and in-flight mmHg), on the tilt table, during acceleration physical exercise. (2.5 +Gz), and during exercise (17 mkp/sec) at sea level and at moderate simulated altitude 49. Kokova NI. (578 mmHg), heart rates were significantly Effect of fluid and salt supplements to food allowance on endurance of head- lower for highly trained athletes, 20-25 percent, than in non-athletes. In maximum to-pelvis accelerations following 7- tolerance tests, however, there was found day 'dry' immersion and under only a significant difference between the two ordinary motor activity conditions. groups for maximum oxygen uptake at Kosmicheskaya Biologiya i physical exercise, but no indication was seen Aviakosmicheskaya Meditsina for a positive cross-adaption effect of 18:33-37, 1984. physical exercise training on the other Author's Abstract stressors. Statistical analysis of the

18 The effect of water-salt supplements as an Our investigations helped to assess the agent increasing human tolerance to head-to- threshold of human tolerance to accelerations feet acceleration with a slow onset was after an exposure to simulated weightlessness examined. The test subjects were rotated in a and to delineate the value of real risk. The 7.25 m centrifuge after 7-day dry immersion tolerance limit to +Gz accelerations which or normal motor activity. The water-salt followed simulated weightlessness of the supplements were given at a dose of 0.15 g above duration ranged from 9.5 to 13.0 g, NaCI and 18 ml water per kg body weight averaging 11.6 _+ 1.6g. (with the total dally dose consumed in four The information on the tolerance of fractions). During immersion fluid retention Soviet and American astronauts to was significantly higher than during normal decelerations shown during re-entry in real activity (818 + 139.7 ml versus 478 + 69 space flights give support to the laboratory ml). Water-salt supplements consumed results and predictions. produced a positive effect on tolerance to head-to-feet acceleration. During 51. Kotovskaya AR, RV centrifugation after water-salt Vartbaronov, SF Simpura. supplementation the physiological responses Human physiological reactions during were less strained. Water-salt supplements the action of transverse accelerations taken on the last immersion day increased the following hypodynamia. tolerance level as compared to the control. Problemy Kosmicheskoy Biologii The amount of the fluid retained in the body 6:106-117, 1967. was found to be inversely proportional to the Authors' Abstract tolerance level. It is concluded that water-salt The physiological reactions to, and supplements may be recommended to tolerance for +Gx accelerations were studied increase tolerance to head-to-feet acceleration in tests on subjects following hypodynamia in aerospace medicine. which lasted from 7 to 20 days. Examinations were made of the bioelectric 50. Kotovskaya AR. activity of the heart, the cerebral cortex, the Human tolerance to acceleration after function of external respiration, the arterial exposure to weightlessness. pressure, and the visual function. The Life Sciences and Space Research decrease in tolerance to accelerations in all 14:129-135, 1976. cases averaged 2 G units (range 1.2 to Authors' Abstract 4.0G), and did not depend on the duration of The major role in the genesis of varying hypodynamia. Physiological reactions to human tolerance to decelerations that follow accelerations were greater following weightlessness is evidently played by hypodynamia. The decrease in tolerance to hypodynamic and hydrostatic factors. accelerations was caused mainly by a Long disuse of compensatory antigravity disorder in the regulation of the vascular mechanisms in weightlessness may bring tonus. about their deconditioning and reduction of their functional capabilities, and may finally 52. Kotovskaya AR, RA affect general tolerance of crewmembers to Vartbaronov, SF Simpura. decelerations. Change in load-factor tolerance after Laboratory experiments demonstrated 70 days of hypodynamia. changes in the human tolerance to Gz Problemy Kosmicheskoy Biologii accelerations of varying duration (from 3 to 13:241-247, 1969. 100 days) and tested the efficacy of different Authors' Abstract countermeasures. Stability to the action of transverse g- A decrease in human tolerance to +Gz is forces was investigated in 12 subjects before on the average 2.0g. It should be noted that and after a prolonged (70-day) confinement an elongation of simulated weightlessness to bed. Overload tolerance was evaluated in (from 7 to 100 days) caused no further terms of the maximum g-force at which the decrease in the +Gz tolerance. first signs of physiological-function

19 disturbancemadetheirappearance,andon analyzers in response to the combined thebasisof shiftsin thephysiological effect of hypokinesia and radial reactionsduringandafteractionof theload acceleration. factor. A distinctdecreasein thetoleranceto Kosmicheskaya Biologiya i transverselydirectedg's wasnotedafterthe Meditsina 1:91-98, 1967. passivesojournin bed. Useof drugs and Authors' Abstract physical exercises during hypodynamia was The functional state of the nervous clearly helpful. The combination of system and some analyzers was studied using prophylactic measures resulted in an increase six healthy male test subjects aged 23-36 in the maximum load factor tolerated after years who had been subjected to a 62-day hypodynamia without any substantial bedrest combined with radial accelerations. decrease of over-all stability. In all cases, Three of the subjects performed physical however, the physiological systems were exercises using a bunjee cord and bicycle more severely stressed under a given g-force ergometer. Prior to the bedrest experiment after hypodynamia. the test subjects were twice (at an interval of 4-6 days) exposed to transverse 53. Kotovskaya AR, RA accelerations. Some transient Vartbaronov, SF Simpura. neuroautonomic disturbances were observed. Change in the capacity of man to The most distinct disturbances were withstand transverse stresses after autonomic and vascular disorders and hypodynamia of varying duration. asthenization phenomena which appeared Problemy Kosmicheskoy Biologii earlier and disappeared later in test subjects 16:46-54, 1971. performing no physical exercises. Some Authors' Abstract functional changes of the acoustic and This work presents study of the capacity vestibular analyzers also were noted. They of 20 men to withstand transverse stresses were related to an increase of the acoustic (+Gx) after hypdodynamia placed in a supine thresholds and decrease of the vestibulo- position for a length of 3 to 60 days. autonomic tolerance. The functional changes Gradual reduction in the resistance to the of the nervous system and some analyzers action of maximum stresses was detected at occur due to hemodynamic disturbances and time periods of hypodynamia from 7 to 15-20 afferent-efferent changes. days: Later, resistance to stresses was preserved approximately at the same level up 55. Leach CS, PC Johnson, TB to the 60 t_day of hypodynamia. Similar Driscoll. shifts were obtained in a study of the Effects of bedrest and centrifugation reactivity of the cardio-vascular and breathing of humans on serum thyroid function systems to stresses determined according to tests. the level of pulse strain and increase of Aerospace Medicine 43:400-402, pulmonary ventilation before and after 1972. hypodynamia of varying duration. The Authors' Abstract results obtained give a basis for supposing Changes in plasma volume and protein the existence in the process of hypodynamia concentration have been reported when of two phases in reactions of an organism to normal subjects are bedrested or centrifuged. stress. In the opinion of the authors, the Since thyroid hormones are transported by presence of the second phase (stabilization) specific plasma proteins, each of these may support the development of a unique procedures could be expected to change adaptation to conditions of hypodynamia. plasma levels of these hormones. In this study centrifugation of normal healthy human 54. Krupina TN, AYa Tizul, NM subjects produced an increased concentration Boglevskaya, BP Baranova, E1 of total protein and albumin. When these Matsnev, YeA Chertovskikh. same subjects were bedrested for six days, Functional changes in the nervous no change in total proteins, albumin or system and functioning and certain thyroxine binding globulin were found

2o althoughtherewasaneightpercentdecrease were higher than during control or bedrest in plasmavolume. Centrifugationand,to a periods. The retention of fluids and lesserextent,bedrestproducedchangesin electrolytes after +Gz may at least partially serumT-4 levelsandtheT-3 Testresults. explain decreased urine volume and increased Thedirectionof thesechanges(decreased% osmolality observed during bedrest in this T-3 valuesandincreasedT-4 levels)indicate study. There were some statistically thatthesetwo situationsproduceanincreased significant differences between the sexes and plasmaconcentrationof thyroxinebinding age groups. Results of the study indicated sites. that space flight would not affect the fluid and electrolyte metabolism of females or older 56. Leach CS, J Vernikos-Danellis, males any more severely than it has affected JM Krauhs, H Sandier. that of male or female astronauts. Endocrine and fluid metabolism in males and females of different ages 57. Lohrbauer LA, RL Wiley, SJ after bedrest, acceleration, and lower Shubrooks, M McCally. body negative pressure. Effect of sustained muscular Houston, TX: Johnson Space contraction on tolerance to +Gz Center. NASA Technical acceleration. Memorandum 58270, 1985. 52p. Journal of Applied Physiology Authors' Abstract 32:203-209, 1972. Space Shuttle flight simulations were Authors' Abstract conducted to determine the effects of The increase in +Gz acceleration (the weightlessness, lower body negative inertial force vector acting in a head-to-foot pressure (LBNP), and acceleration on fluid direction) tolerance afforded by static forearm and electrolyte excretion and the hormones muscular contraction (handgrip) was that control it. Measurements were made on evaluated and compared with that of the male and female subjects of different ages standard G suit. Acceleration tolerance was before and after bedrest. After admission to a assessed in eight subjects in each of four controlled environment, groups of 6 to 14 conditions for both rapid onset ( 1.0 G/s) and subjects in the age ranges 25 to 35, 35 to 45, slow onset (0.1 G/s) acceleration profiles. 45 to 55, and 55 to 65 years were exposed to The conditions were: 1) unprotected, 2) +3 Gz for 15 minutes (G1) and to LBNP handgrip, 3) G suit, and 4) handgrip and G (LBNP1) on different days. On 3 days suit. The mean tolerance levels achieved for during this pre-bedrest period, no tests were those four conditions for the rapid onset runs conducted. Six days of bedrest followed, as defined by peripheral light loss were 3.6, and the Gz (G2) and LBNP (LBNP2) tests 4.3, 4.8, and 5.4 G, respectively. For the were run again. Hormones, electrolytes, and slow onset runs, the tolerance levels were other parameters were measured in 24-hour 4.6, 5.6, 5.8, and 6.3 G. Thus the handgrip urine pools throughout the experiment. and G-suit procedures each provided During bedrest, cortisol and aldosterone approximately 1 G of protection. excretion increased. Urine volume Significantly, the effect of the two procedures decreased, and specific gravity and combined proved to be additive. In the rapid osmolality increased. Urinary electrolytes onset runs, the static contraction was begun 60-90 s before the onset of acceleration and, were statistically unchanged from levels during the non-stress control period. During in the slow onset runs, the contraction was G2, cortisol increased significantly over its begun with the onset of acceleration. The control and bedrest levels. Urine volume, protection provided by the static sodium, and chloride were significantly concentration is, at least in part, due to the lower; specific gravity and osmolality were increase in mean systemic blood pressure higher during G2 than during the control which accompanies any such contraction. period or bedrest. During LBNP2, volume This increase prolongs the time necessary for was lower than during the non-stress control acceleration to result in a blood pressure period, and specific gravity and osmolality below intravascular pressure, this latter being

21 thetimeatwhich peripherallightlossoccurs. established. We conclude that tolerance to Unlike duringrespiratorystraining +Gz acceleration before and after simulated maneuvers,no increasein intrathoracicor weightlessness is independent of inherent intra-abdominalpressureoccurredduring aerobic fitness. handgripexerciseat 1G. 59. Meehan JP, JP Henry, S Brunjes, 58. Ludwig DA, VA Convertino, DJ H deVries. Goldwater, H Sandier. Investigation to determine the effects Logistic risk model for the unique of long-term bed rest on G-tolerance effects of inherent aerobic capacity on and on psychomotor performance. +Gz tolerance before and after Los Angeles, CA: University of simulated weightlessness. Southern California School of Aviation, Space, and Environmental Medicine. Final Report No. NAS Medicine 58:1057-1061, 1987. 9-3500, August, 1965.48p. Authors' Abstract Author's Abstract Small sample size (n<10) and Fourteen young men were confined to inappropriate analysis of multivariate data bed for 28 days. They were randomly have hindered previous attempts to describe divided into three subject groups of 5, 5 and which physiologic and demographic variables 4 individuals. One group exercised, another are most important in determining how long did pressure breathing and the third did both. humans can tolerate acceleration. Data from Each subject was exposed to a re-entry previous centrifuge studies conducted at acceleration profile in the -Gx position while NASA/Ames Research Center, utilizing a 7- performing a three dimensional tracking task 14 d bed rest protocol to simulate prior to the bed rest and at the conclusion of weightlessness, were included in the current the bed rest. Tilt table tolerance and blood investigation. After review, data on 25 volumes were determined in a similar women and 22 men were available for sequence. analysis. Study variables included gender, Cardiovascular deconditioning manifested age, weight, height, percent body fat, resting by plasma volume decrements of 20% and heart rate, mean arterial pressure, VO 2 max, decreased tolerance to passive tilting resulted and plasma volume. Since the dependent in all subjects and was not differentially variable was time to greyout (failure), two affected by the exercise, pressure breathing contemporary biostatistical modeling or the combination maneuvers. procedures (proportional hazard and logistic Performance on the tracking task during discriminant function) were used to estimate acceleration was not affected by the risk, given a particular subject's profile. cardiovascular deconditioning. After adjusting for pre-bed-rest tolerance time, none of the profile variables remained 60. Mikhaylovskiy GP, TV in the risk equation for post-bed-rest Benevolenskaya, TA Petrova, tolerance greyout. However, prior to bed IYa Yakovleva, OI Boykova, rest, risk of greyout could be predicted with MP Kuz'min, AA Savilov, SN 91% accuracy. All of the profile variables Solov'yeva. except weight, MAP, and those related to The combined effect of two-month hypokinesia and radial accelerations inherent aerobic capacity ( VO 2 max, percent on the cardiovascular system. body fat, resting heart rate) entered the risk Kosmicheskaya Biologiya i equation for pre-bed-rest greyout. A cross- Meditsina 1:86-90, 1967. validation using 24 new subjects indicated a Authors' Abstract very stable model for risk prediction, accurate Six healthy male test subjects were within 5% of the original equation. The result for the inherent fitness variables is exposed to a 62-day bedrest and radial accelerations of the maximum tolerable significant in that a consensus as to whether magnitude. The bedrest reduced the strength an increased aerobic capacity is beneficial or of the muscular vessels, disturbed the detrimental has not been satisfactorily

22 ophthalmicandnasalregionalcirculationand As judged by the degree of physical decreasedtheorthostatictoleranceof all the discomfort, the ability to respond to a central subjects.Thelatterwasassociatedwith light, or the presence of electrocardiographic somecardiovasculardisordersand abnormalities, tolerance to +Gx was deteriorationof circulatorymechanismsof unaffected by 4 weeks of absolute bed rest. adaptationto aphysicalload. Thecombined In each subject studied, heart rates during effectof bedrestandradialaccelerationson peak acceleration were higher after bed rest thecardiovascularsystemwasmoredistinct than before. thantheeffectof accelerationsalone. As judged by the level of acceleration at Physicalexercisesperformedduringbedrest which central vision was lost, no significant yieldedpositiveresults. change in tolerance to headward (+Gz) acceleration of rapid onset was observed after 61. Mikhaylorskiy GP, NN 2 weeks of modified bed rest or after 4 weeks Dobronravova, MI Kozar, MM of absolute bed rest. After each type of bed Korotayev, NI Tsiganova, VM rest, the majority of the subjects had Shilov, IYa Yakovleva. decreased tolerance to headward (+Gz) Variation in overall body tolerance acceleration of gradual onset, but the mean during a 62-day exposure to decrease was not statistically significant. hypokinesia and acceleration. Mean heart rates at equivalent levels of Kosmicheskaya Biologiya i +Gz were significantly higher after both Meditsina 1:66-77, 1967. periods of bed rests. The only arrhythmia of Authors' Abstract clinical importance noted was the appearance The overall tolerance of the human body of bursts of premature atrial contractions was studied on six healthy male subjects during G.O.R. +Gz in 1 subject after 2 weeks of bed rest. during a 62-day period of hypokinesia. Beginning with the third week of the experiment the protective properties of the 63. Murdoch DM, LG Meyer, RP Crisman. body deteriorated considerably (quantity of blood properdin, phagocytic activity of Effects of running and weight lifting on +Gz tolerance. neutrophils, lysozymic activity of the saliva and bactericidal function of the skin). In Aviation, Space, and Environmental addition to inhibition of natural immunity Medicine 59:475, 1988. (Abstract) there was development of inflammatory Authors' Abstract diseases, mostly affecting the mucous Introduction: membranes and the vascular system. The Previous studies have shown the benefit results obtained should be taken into account of resistance training over aerobic training to in developing preventive measures for use enhance +Gz-tolerance. Aircrew members during prolonged space missions. continue to enjoy aerobic exercise for recreation and health. We studied the effects 62. Miller PB, SD Leverett Jr. of a regular aerobic training program on both Tolerance to transverse (+Gx) and the physiological benefits gained from a headward (+Gz) acceleration after weight lifting program and G-tolerance. prolonged bed rest. Methods: Aerospace Medicine 36: 13-15, Twenty-four student naval aviators and 1965. student naval flight officers were tested for Authors' Abstract aerobic capacity, and muscular strength and Tolerance to the transverse (+Gx) endurance before and after a 10-week acceleration of a simulated Gemini re-entry conditioning program. Subjects were profile was determined before and after 4 randomly divided into two groups of weight weeks of absolute bed rest. Tolerance to lifting only (WL) (n = 10) and weight lifting headward (+Gz) acceleration was studied and running (WR) (n = 13). The weight before and after 4 weeks of absolute bed rest lifting program was performed 4-days per and 2 weeks of modified bed rest. week, 2 muscular strength and 2 muscular

23 enduranceworkouts. TheWR grouprana bedrest, immediately following, and 5 d later meanof 12.7mi/week. Physicalfitness showed that average +Gz tolerance decreased assessmentwasaccomplishedbothprior to by 67% after bedrest. andfollowing thetrainingprogram.Gradual onsetrate(GOR)andsimulatedair combat 65. Parnell M J, JE Whinnery. maneuver(SACM)G-tolerancewere The effects of long term aerobic assessedfollowing the 10-weekconditioning conditioning on tolerance to +Gz program. stress. Results: Aerospace Medical Association No statistically significant differences Preprints, 1982. p.22-23. were seen between the WL group and the (Abstract). WR group for any of the measured physical Annotation fitness parameters for either pre- or post- Purpose: training. Mean post GOR tolerances for the To investigate the relationship between WL and WR groups were 9.24 and 9.05 intense aerobic conditioning and tolerance to +Gz, respectively. Mean post SACM times +Gz stress by investigating the response of for the WL group was 134.6 and 153.6 s for marathon trained runners on the centrifuge. the WR group. Neither the GOR nor SACM Method: tolerances differed significantly for the To measure tolerance to +Gz stress, each groups. subject rode a standard USAFSAM medical Conclusions: evaluation protocol on the centrifuge Moderate levels of running accompanied consisting of a gradual onset ( IG/I 5 sec) by weight training were not detrimental to G- +Gz exposure in relaxed state, a series of tolerance. rapid onset (IG/sec) in a relaxed state, and a 64. Newsom BD, WL Goldenrath, GOR exposure where subjects performed WR Winter, H Sandier. anti-G straining maneuvers. Tolerance of females to +Gz Results: centrifugation before and after There was no increase in tolerance to +Gz bedrest. stress associated with intense aerobic Aviation, Space, and Environmental training, and at least a low average tolerance Medicine 48:327-331, 1977. for these subjects when compared to data in Authors' Abstract the USAFSAM acceleration repository. Because women may be included as Percent body fat and 40 2 max data passengers in the proposed Space Shuttle illustrate trained subjects. Endurance training System, this study was designed to enhances cardiovascular vagal tone, investigate the +Gz tolerance of women and evidenced by lower heart rates. Increased the possible degradation of this tolerance after motion sickness including vomiting, may be a period of weightlessness as simulated by evidence of enhanced vagal tone through bedrest. Twelve healthy Air Force flight vagal innervation of the GI tract. nurses served as test subjects. Over a 1- Conclusion: week period, each subject was exposed to Tolerance to +Gz stress can be influenced +Gz levels starting at +2 Gz and increasing by the type of physical conditioning HPA by 0.5 Gz increments to a grey-out point. pilots perform. Intense aerobic training is not This point was determined by peripheral necessary to prepare a pilot to combat +Gz vision loss with a standard lightbar and by stress, and may decrease ability to perform in reverse blood flow in the temporal artery. a high +Gz environment. Ultimately, each women was subjected to three runs at the +3 Gz level; each run was 66. Petrovykh VA, RV Kudrova, MI approximately 55 min long, separated by 5- Kuznetsov, PP Lobzin, IG min rest periods. Eight subjects with the best tolerance times were selected for 14 d of Popov, IA Romanova, YuK Syzrantsev, AM Terpilovskiy, bedrest in a horizontal position; the other four YuF Udalov, NA Chelnokova. were ambulatory controls. Tests before

24 Nutritionalstateof humansubjects nervous system, electroencephalographic keptfor longperiodsin ahorizontal recordings, physiological tremor and positionandsubsequentlyexposedto fluctuations of the body center of gravity acceleration. (stabilography). Results: 1. During the first Problemy Kosmicheskoyi Biologii two weeks of the experiment the test subjects 1:355-363, 1967. exhibited symptoms of asthenic reactions in Annotation their behavior and nervous system. 2. Later Purpose: the symptoms become more serious, To study the nutritional state of a human acquiring the form of neurological symptoms subject kept in a horizontal position and with and an asthenic syndrome (neurasthenia). 3. restricted movement. An analysis of data on the tremor, Method: electroencephalogram and stabilography also indicated the development of changes in the Aspects of nutritional state of subjects central nervous system, autonomic nervous during hyperdynamia and preceding exposure to overloading were carried out on 3 healthy system and orthostatic tolerance in response young persons (22-24 years) for 10 and 15 to long-term hypokinesia. Functional shifts were accompanied by morphological changes days. Results: in the muscular system. There was no significant difference 68. Rusko H, P Kuronen, P Tesch, U between uropepsin levels in subjects' urine Balldin. during hypodynamia and in the initial state; Effects of aerobic and strength thus, there was no change in enzyme function training on physical fitness and G- of the gastric glands on feeding the tolerance of fighter pilots. experimental diet under these conditions. Negative nitrogen balance was observed in all Aviation, Space, and Environmental subjects during the initial period of Medicine 59:474, 1988. (Abstract). Authors' Abstract hypodynamia. Increase excretion of urea, ammonia, and uric acid in urine also Introduction: occurred. There were no significant changes Strength training has been shown to in blood cholesterol with the diet and improve the G-tolerance, contrary to aerobic hypodynamia. There was, however, a training. In our previous study modified decrease in blood sugar due to do utilization endurance training was also able to increase of CHO. G-tolerance of fighter pilots. This study Conclusion: investigated the effects of changes from The diet investigated proved adequate in aerobic to strength training and from strength its nutritional value and content of basic food to aerobic training on physical fitness and G- substances for the subjects kept under tolerance of fighter pilots. hypodynamic conditions preceded by Methods: overloading, with the exception of its content After one year of combined strength and of certain vitamins. aerobic conditioning 8 pilots started a modified endurance training (3 times a week) 67. Purakhin YuN, BN Petuknov. for 9 weeks and thereafter trained 9 weeks Neurological changes in healthy strength training (3-4 times a week). Another subjects induced by two-month group of 8 pilots started first the 9 week hypokinesia. strength training and thereafter the modified Kosmicheskaya Biologiya i endurance training for 9 weeks. Physical fitness and G-tolerance was measured before Meditsina 2:51-56, 1968. Authors' Abstract the experimental period, after the first 9 Six healthy male test subjects were twice week, period and after the second 9 week exposed to acceleration followed by a 62-day period. Results: bedrest during which three test subjects performed physical exercises of a known Both groups improved significantly the intensity. The study included tests of the maximal isometric leg extension (LEF) and

25 trunk extension(TEF)forces,aswell asG- with G-tolerance. When the two tolerance,significantlyduringthefirst 9 measurements were combined (n = 38) TFF, weekperiod. In addition,strengthtraining TEF and JUHE were found to correlate improvedthemaximalisometrictrunkflexion significantly with G-tolerance (p<0.01). force(TFF)significantly. Duringthesecond Conclusions: 9 weekperiodthemodifiedendurance Although a good overall fitness seems to trainingdecreasedsignificantlyLEF,TFF be necessary for the pilot, the abdominal and andG-tolerance.Thestrengthtraining back muscle strength are the most indicative improvedfurtherTFF whilethechangesin characteristics. TEF, LEFandG-tolerancewere insignificant. 70. Sandier H, D Goidwater, SA Conclusions: Rositano. G-tolerance and muscular force are Physiologic response of male subjects decreased if endurance training is started after ages 46 to 55 years to Shuttle flight strength training period. simulation. Aerospace Medical Association 69. Rusko H, P Kuronen, P Tesch, U Preprints, 1979. p.43-44. (Abstract). Balldin. Authors' Abstract Relationship between G-tolerance and The present study was conducted on physical fitness of fighter pilots. seven untrained older male subjects (ages 46 Aviation, Space, and Environmental to 55) to assess the magnitude of Medicine 60:512, 1989. (Abstract). physiological changes occurring during a Authors' Abstract ground-based simulation of Shuttle flight. In Introduction: addition, G-suit effectiveness was evaluated Strength training has been shown to as a countermeasure for the expected increase the g-tolerance in fighter pilots, cardiovascular deconditioning occurring with contrary to aerobic training. During a M-1 bed rest (10_ days) since it is anticipated maneuver the pilots are supposed to activate that antigravity suits will be used or provided both abdominal and leg musculature. This for use during future Shuttle missions. On study investigated the correlations between g- the seventh day of BR, each subject received tolerance and variables related to the strength +1.5 Gz with a G-suit and without a G-suit. and endurance of the fighter pilots. On the following day, the subjects underwent Methods: +2 Gz with and without a G-suit. On the The pilots (n = 19) were studied twice ninth day, the subjects received +3 Gz with with 6 months' interval. G-tolerance was and without a G-suit. Blood pressure and measured with repeated 15 s periods at 3.5 heart rate were monitored. All parameters and 5.5 G without anti-G-suit until increased significantly during acceleration exhaustion. both before and after BR. G-suit usage Results: before and after BR resulted in significantly In the first measurement of isometric leg lower heart rate at + 1.5 Gz and +2 Gz and extension (LEF, r = .46, p<0.05), trunk higher systolic and diastolic blood pressures flexion (TFF, r = .59, p<0.01) and trunk at all three G levels. In conclusion, older extension (TEF, r = .57, p<0.01) forces as individuals have some degree of protection well as jumping height (JUHE, r = .78, during Gz, probably due to loss of vascular p<0.001) correlated significantly with G- elasticity with the aging process. tolerance. Maximal oxygen uptake (r = .63, p<0.001) and maximal blood lactate 71. Sandier H, P Webb, J Annis, N concentration (r = .57, p<0.01) after Pace, BW Grunbaum, D treadmill running test to exhaustion also Dolkas, B Newsom. correlated highly significantly with G- Evaluation of a reverse gradient tolerance. In the second measurement only garment for prevention of bed-rest TFF (r = .48, p<0.05) and TEF (r = .49, deconditioning. p<0.05) demonstrated significant correlations

26 Aviation, Space, and Environmental 73. Shulzhenko EB, IF ViI-Vilyams, Medicine 54: 191-201, 1983. MA Khudyakova, AI Authors' Abstract Grigoryev. A reverse gradient garment (RGG) was Deconditioning during prolonged used to intermittently induce venous pooling immersion and possible in the extremities of a magnitude similar to countermeasures. that seen in going from a lying to standing Life Sciences and Space Research position during the course of a 15-d period of 14:289-294, 1976. horizontal bed rest. Venous pooling failed to Authors' Abstract improve bed-rest-induced losses in +2.5 Gz Test subjects, covered with a waterproof and +3.0 Gz centrifugation tolerance or to highly elastic cloth, were exposed to 13-day prevent increased heart-rate responses to water immersion up to the neck. They were lower-body negative pressure (LBNP). Four divided into two groups. The first (control) subjects served as controls, four were group consisting of six persons was exposed treated. Tests during the 7-day recovery to immersion alone and the second period showed fluid/electrolyte and body (experimental) group was exposed daily to composition values to have returned to pre- accelerations of 0.6-2 Gz for 60-90 min bed-rest levels with continued depression of during the last 6 days of immersion. Before acceleration tolerance times (56% decreased and after immersion all the test subjects were at +2.5 Gz and 74% decreased at +3.0 Gz exposed to +3 Gz for 5 min which served as compared to pre-bed-rest levels) and a provocative test. These experiments give exaggerated blood insulin response on evidence that the use of dry immersion allows glucose tolerance testing (blood insulin for experimentation during prolonged immersion treated group increased 95% at 1 h before bed without concomitant complications. rest and 465% during recovery). This study Variations in the physiological parameters demonstrates that the physiologic changes (cardiovascular system, fluid-electrolyte after bed rest persist for significant periods of balance, blood-coagulatory system) are time. Acceleration tolerance time proved to indicative of the preventive effect of periodic be a sensitive test for the deconditioning accelerations during 13-day immersion. process. 74. Shul'zhenko YeB, VG Koziova, 72. Shulzhenko EB, IF Vil-Vilyams, KA Kudrin, AS Yarov, VG EA Aleksandrova, KI Gogolev. Piokhova. Prophylactic effects of intermittent G suit of bladderless type as a means acceleration against physiological of improving orthostatic stability after deconditioning in simulated water immersion hypokinesia and weightlessness. exposure to accelerations. Life Sciences and Space Research Kosmicheskaya Biologiya i 17:187-192, 1979. A viakosmicheskaya Meditsina Authors' Abstract 17:30-33, 1983. The prophylactic effect on adult human Authors' Abstract males of intermittent acceleration against Orthostatic tolerance after 7-day dry physiological deconditioning in immersion and head-to-feet acceleration was weightlessness simulated by water immersion investigated on test subjects with and without was studied at +0.8, +1.2, and +l.6g. an antigravity suit of bladderless type. With These prophylactic exposures reduced renal the suit on, the 20 min tilt test at 70 Uprior to excretion of fluid and plasma volume immersion induced less marked changes than changes, and increased venous compliance without the suit. When the suit was on, and the time at which the subjects could cardiovascular reactions to tilt tests after tolerate an acceleration field of +3 g. immersion and acceleration improved. The maximum heart rate decreased from 135 + 4 to 101 + 5 beats/min (p<0.01), minimum stroke volume increased from 29 + 2 to 41 +

27 3 ml (p<0.05)andpulsepressuregrew. lack of statistically different tolerance Thus,an antigravitysuitmayhelpincrease between the groups. initial orthostatictoleranceandmaintainit Conclusion. afterthecombinedeffectof simulated The lack of statistical significance hypogravityandacceleration. between groups or trials on heart rate response to an equal G stress supports the 75. Spence DW. finding that abdominal muscle conditioning Abdominalmuscleconditioningasa did not increase G-tolerance. meansof increasingtoleranceto +Gz stress. 76. Suvorov PM. Aerospace Medical Association Influence of thirty-day hypokinesia in Preprints, 1981. p.148-149. combination with exposure to LBNP (Abstract). on tolerance to accelerations (+Gz). Annotation Kosmicheskaya Biologiya i Purpose: Aviakosmicheskya Meditsina 8:65- To determine the effects of specific 68, 1971. abdominal muscle conditioning on +Gz Author's Abstract tolerance. A study was made of the effect of Method: hypokinesia combined with LBNP on Twenty male volunteers (18-38 yrs) were tolerance to accelerations. Before and after randomly assigned to two groups after hypokinesia the subjects were centrifuged at completing baseline measurements of 3 g for 30 sec and at 5 g as long as it could be anthropometry, body composition, muscular tolerated. Two days after exposure to strength and endurance (MVTC), G-tolerance hypokinesia and LBNP the duration of and heart rate response to G stress. tolerance to accelerations of 5 g was 24.2- Group 1 consisted of the abdominal muscle 36.5% of the initial level. This may be conditioning (AMC) subjects, which brought about by the functional activity of the followed an AMC program 3 times per week muscular system and venous tone which for 12 weeks (36 workouts). Group 2 results in a marked decrease in systolic consisted of the control subjects (C) who did volume and cardiac output during exposure to no abdominal conditioning. accelerations and accordingly in the early During the 12 week experimental period development of optic disturbances. both groups underwent a centrifugation profile of alternating 15 second plateaus at 77. Tesch PA, H Hjort, UI Balldin. 4.5 and 7.0 +Gz until fatigue or visual loss Effects of strength training on G criteria were met ( 100% peripheral or 50% tolerance. central light loss). The centrifuge protocol Aviation, Space, and Environmental for both groups was followed weekly for Medicine 54:691-695, 1983. four weeks then bi-weekly for eight weeks. Authors' Abstract Determinations of abdominal muscle strength The G tolerance of pilots flying modern, and endurance were made on the AMC group high-performance fighter aircraft is crucial. four times during the experimental period. Therefore, methods to increase G tolerance Baseline measurements were performed again are of vital importance. In this study, G at the end. tolerance was studied in a human centrifuge Results: using simulated aerial combat maneuvers 1) Muscular strength and endurance to (ACM)--consisting of 15-s periods of 4.5 increased significantly (p<0.01) during the and 7 G until exhaustion--before and after 11 conditioning program up to a maximum of weeks of muscle strength training. The 177%. ACM-time in 11 fighter pilots was increased 2) However, further centrifuge training after this training by 39%. Gains were adaptation had occurred which was not observed in knee extensor muscle strength significantly affected by the muscle during slow contractions by 17% and in conditioning program as evidenced by the anaerobic power by 14%. Aerobic

28 performanceandvariousmuscle hypohydrated ambulatory subjects, there is histochemicalindices,asassessedfrom an isotonic loss of plasma fluid; (d) musclebiopsysamplesobtainedfrom m. centrifugation tolerance was significantly vastuslateralis,wereunchanged. reduced following bedrest; and (e) the two Neuromuscularadaptationseemsto be exercise regimens had no statistically responsiblefor theincreasedmusclestrength, significant effect upon post-tbedrest aswell asfor theimprovedperformanceof centrifugation tolerance; however, both theM-1 strainingmaneuver.Thismight isometric and isotonic exercise reduced the explaintheenhancedG tolerance. average +Gz tolerance decrement by 85- 100s. 78. van Beaumont W, JE Greenleaf, HL Young, L Juhos. 79. Vil-Vilyams IF. Plasma volume and blood constituent Principle approaches to selection of shifts during +Gz acceleration after the short-arm centrifuge regimens for bedrest with exercise condition!ng. extended space flight. Aerospace Medicine 45:425-430, Acta Astronautica 33:221-229, 1974. 1994. Authors' Abstract Author's Abstract The purpose of the present study was to Eight +Gz regimens on the SAC varying investigate the influence of isometric and in their values (within 0.8 to 1.6 G), isotonic exercise during bedrest on plasma exposures, schedules, etc. were analyzed. volume (PV) and blood constituents during Some regimens were combined with water- +Gz acceleration in seven young men. salt supplements (WSS) or veloergometer During bedrest, PV decreased between 8.0% training (VE). Weightlessness was simulated and 11.5%. During centrifugation before by 3- to 28-day water immersion. +3 Gz bedrest, the average decrease in PV was loads on the centrifuge with the radius of between 10.7% and 13.2%, with 7.5m were applied prior to and post concomitant plasma protein losses of 2.6% to immersion. Regimens for human runs on the 3.7%, and albumin losses of 1.2% to 4.6%; SAC as a novel, perspective countermeasure after bedrest, the corresponding changes with for interplanetary expeditions should be centrifugation were between -6.3% to -7.1%, selected with due regard of the human - 1.1% to -2.0%, and +2.4% to -3.1%, tolerance, their efficiency, and subsequent respectively. The average acceleration verification and specification in orbital tolerance during pre-bedrest control runs was flights. These approaches showed that 3 1,129 _SE 27 s, while after bedrest, the days of exposure to 1.2 G combined with mean tolerance was 817 _SE 31 s (p < 0.05). WSS and 6 days of exposure to G-loads For comparative purposes, additional from 0.8 to 1.6 G together with VE were hematological changes with centrifugation most optimal. were evaluated from nine different hypovolemic, ambulatory subjects. During 80. Vil-Vilyams IF, YeB +Gz acceleration there was an isotonic loss of Shul'zhenko. plasma fluid (8.6% to 11.2%) with respect to Cardiac arrhythmia following serum sodium, potassium, chloride, postimmersion +Gz accelerations. creatinine, and osmolarity; however, serum Kosmicheskaya Biologiya i glucose concentration increased between Aviakosmicheskaya Meditsina 6.3% and 19.3%. It is concluded that during 12:50-56, 1978. acceleration (a) the mean reduction in PV and Authors' Abstract protein contents after bedrest is about half as Cardiac arrhythmia is a common disorder great as during the control runs before occurring under the influence of altered bedrest; (b) isometric and isotonic exercise gravity. Thus, under the influence of during bedrest have no effect on the decrease accelerations, extrasystolic arrhythmia, sinus in PV and protein contents during arrhythmia and relative bradycardia are the centrifugation; (c) during +Gz acceleration, in most typical forms of rhythm disturbances

29 dueto accelerations.Underweightless work and his ability to withstand high conditions,spacecraftcrewsnot headward acceleration. uncommonlydevelopedrhythmdisordersin University of Southern California, theform of isolatedandsystemic Los Angeles, CA: Ph.D. extrasystoles. Dissertation, 1950. 109p. Immersionis oneof theground-based Author's Abstract modelsof weightlessness.However,there 1. An investigation was made of the hasbeenlittle studyof arrhythmiasoccurring relationship between fitness for strenuous undertheinfluenceof immersionfollowedby work and G-tolerance in twenty-three healthy exposureto accelerations.Weonly know male university students. that,in onestudydealingwith human 2. The study was designed to determine subjects,an attackof paroxysmaltachycardia the relationship between the subjects' developedin asubject23h afterdropping tolerance to +5 G and their fitness for into theimmersionmedium.Post-immersion strenuous work; to study the effects of a functionalloadtestsrevealedmoremarked training program on the subjects' G- sinustachycardiathanin controlstudies. tolerance; and to investigate the influence of Our objectiveherewasto investigatethe cessation of systematic training on G- effectof immersionfollowedbyhead-pelvis tolerance. accelerationson distinctionsof development 3. Fitness for strenuous work was of cardiacarrhythmia. measured by means of performance tests, namely, the Harvard Step and Army Air 81. Vil-Vilyams IF, YeB Force Tests and the hand dynamometer Shul'zhenko. strength test. Functional state of the cardiovascular 4. Each subject was exposed to +5 G system under the combined effect of until he greyed out or for a maximum run of 28-day immersion, rotation on a 30 seconds. G-tolerance was measured in short-arm centrifuge and exercise on a terms of earopacity during acceleration and bicycle ergometer. during an 8 minute recovery period, and Kosmicheskaya Biologiya i pulse rates during an 8 minute recovery Aviakosmicheskaya Meditsina period after acceleration for those subjects 14:42-45, 1980. who endured +5 G for 30 seconds; and time Authors' Abstract until grey-out for those subjects who greyed The cardiovascular function of four test out at +5 G. subjects exposed to 28-day "dry" immersion 5. The basic exercises used in the six and was examined before and after 6-day cycles a half weeks' training program were weight of rotation in a short-arm centrifuge to training and running. These items were provide 1-2 Gz, bicycle ergometer exercise, selected because of their high components of and their combination. An exposure to muscular strength and cardiovascular acceleration of 3 Gz in a 7.25 m arm endurance. Each subject participated at least centrifuge was used as a provocative test. three times weekly in the training program. The above countermeasures reduced but not 6. During the eight weeks' period after eliminated entirely immersion-induced training had ended, the subjects were cardiovascular deconditioning. From this requested to participate as little as possible in study a combined use of acceleration of 1-2 organized physical activity. Gz in a short-arm centrifuge and bicycle 7. Analysis of the fitness measures ergometer exercise can be recommended as a revealed that most of the subjects were in countermeasure against cardiovascular "average" physical condition when they deconditioning in weightlessness. started the training program. The level was raised to "good" after training and dropped 82, Wessel JA. somewhat eight weeks after the program An investigation of the relation stopped. between man's fitness for strenuous 8. A statistically significant increase in the Harvard Step Test scores, Army Air Force

30 Testscoresandhanddynamometerstrength with increased +Gz tolerance, it might be wasfoundaftera six andahalf weeks'of the necessary in the future to establish high- systematictraining program. performance fighter aircraft selection 9. G-tolerancemeasuresshoweda standards so that a group of aviators with significantimprovementafterthesix anda super-high +Gz tolerance could be selected to half weeks'of thesystematictraining maintain complete air superiority. Initial program. studies measuring the +Gz tolerance of 59 10.A slightbutconsistentrelationship USAF aircrewmen undergoing aeromedical wasfoundto existbetweenG-tolerance evaluation were made on the USAF School (earopacityat theendof therunandpulse of Aerospace Medicine human centrifuge. ratesimmediatelyafter+5G) andfitnessfor Specific clinically measurable parameters strenuouswork asmeasuredby theHarvard were found to be associated with +Gz StepandArmy Air ForceTests. tolerance. A high +Gz tolerance prototype is 11.A statisticallysignificantdrop-offin described. The parameters associated with fitnessasmeasuredby theArmy Air Force high +Gz tolerance are not necessarily the Testwasfoundeightweeksaftersystematic optimum attributes for the high-performance traininghadstopped.Only aslightdrop-off fighter pilot since these parameters do carry in fitnesswasobservedasmeasuredby the increased risk for cardiovascular disease. HarvardStepTestandhanddynamometer strengthtest. 84. Whinnery JE, MJ Parnell. 12.A statisticallysignificantdrop-offin The effects of long-term aerobic G-tolerancemeasures(earopacityandpulse conditioning on +Gz tolerance. rates)for thosesubjectswhoendureda+5 G Aviation, Space, and Environmental for 30 secondswasnotedeightweeksafter Medicine 58:199-204, 1987. thetrainingprogramstopped.Group Authors' Abstract performanceon the+5G-testrunsshowed Aerobic conditioning programs for nochangein durationof thecentrifugeruns. aircrews of high performance fighter type aircraft are very important in assuring 83. Whinnery JE. optimum fitness and health. The aerobic +Gztolerancecorrelationwith clinical conditioning resulting from running alters the parameters. physiologic state of the individual, and Aviation, Space, and Environmental whether or not this alteration affects +Gz Medicine 50:736-741, 1979. tolerance is unknown. In this study, 27 Author's Abstract long-term (2 years of running) aerobically Increased +Gz stress demands continue conditioned subjects were tested for gradual to be placed on modern high-performance (1 G • 15 s t) and rapid onset (1 G ' s _) +Gz fighter aircraft pilots. Precise definition of tolerance. Maximum 40 2 and percent body normal +Gz tolerance along with a full fat measurements were also performed and understanding of the physiologic and correlated to the +Gz-tolerance anatomic factors that influence +Gz tolerance measurements. Although beneficial for is therefore of increasing importance. If optimum health and fitness, increased aerobic certain subtle medical abnormalities are condition ( %zO2 max) resulting from long- associated with altered +Gz tolerance, it will term running was not found to enhance +Gz be necessary for medical standards to tolerance. No relationship was observed recognize them and to find in what way they between aerobic condition and +Gz tolerance. affect +Gz tolerance. With the cost of fighter aircraft becoming tremendously high, along An increased susceptibility to motion sickness was found to be associated with with the associated high cost of training aviators to fly them, it will become more long-term aerobic conditioning. Certain individuals were found to be predisposed to important to assure safety by selecting only those individuals most suited to tolerate the cardiac rate and rhythm disturbances (A-V dissociation and transient asystole) which multistress environment of the fighter aircraft. If certain parameters are associated could potentially alter +Gz-tolerance. Optimum physical conditioning programs for

31 aircrewof fighteraircrafthaveyetto be method for measuring cardiovascular changes determinedandimplemented.Specificityof at bed rest. exercisetrainingandassuranceof theabsence 5. Tolerance to positive acceleration of exaggeratedcardiovascularresponseto declines during the first 12 hours of bed rest, +Gz stressresultingfrom physiologic remains relatively constant during bed rest, alterationof autonomictonearecriticalto the and improves during ambulation. designof optimumconditioningprogramsfor 6. Losses in body weight were fighteraircraftaircrews. progressive and ranged from 0.98 to 2.35 kg. Average weight loss during the I0-day 85. White PD, JW Nyberg, LM period was 2%. Finney, WJ White. 7. The condition of the experiment Influence of periodic centrifugation resulted in an average loss of 17% in total on cardiovascular function of man blood volume, 26% in plasma volume, and during bed rest. 2% in red blood cell volume. Santa Monica, CA: Douglas Aircraft 8. No significant changes were seen in Co. Inc., Report No. DAC-59286, serum electrolytes, bilirubin, glucose, or 1966. 47p. blood urea nitrogen; in red blood cell, white Authors' Abstract blood cell, or reticulocyte counts; in A study was made of the influence of hemoglobin, hematocrit, or in mean periodic centrifugation on the physiological corpuscular hemoglobin concentration; in disturbances associated with 10 days of bed hearing, or in the postural equilibrium; nor rest. During bed rest the subjects were was there any change in exercise tolerance as scheduled to ride the centrifuge 4 times each measured by the Master's two-step test. day; the duration of each ride was 20 min; 9. No cardiac irregularities or and the magnitude of acceleration was +2.5 arrhythemias were encountered in the testing gz at heart level. Subjects exercised for a 14- of eight subjects during a total of 135 hours day period before the study. The energy cost of positive acceleration. of this exercise was approximately 1,000 10. Application of negative pressure to kcal/day/man. the lower half of the body produces Functional and diagnostic tests conducted cardiovascular changes similar to those seen at regular intervals during the experiment in 700 head-up tilt. Application of a pressure revealed the following: differential of 70 mmHg to subjects after l0 1. The prescribed regimen of +2.5 gz for days of bed rest produced presyncopal 20 min exceeded tolerance to positive symptoms in 2 to 4 min. During the acceleration. The modal conditioning prerecumbency period, these two subjects regimen was +1.75 gz for 20 min 4 times tolerated 20 min of negative pressure without each day. When the magnitude of symptoms. acceleration is referenced to foot level, the integrated g-time is 4.7 g-hours. 86. White PD, JW Nyberg, LM 2. Expected deterioration produced by Finney, WJ White. recumbency in the ability to tolerate 700 head- A comparative study of the up tilt for 20 min was largely alleviated by physiological effects of immersion periodic centrifugation, as judged by and bed rest. syncopal episodes and highest orthostatic Santa Monica, CA: Douglas Aircraft heart rates. Company Inc., Report No. DAC- 3. The conditioning regimen did not 59226, I996. 77p. appear so effective as shorter g-time Authors' Abstract integrals, as judged by highest orthostatic The purpose of the study was to compare heart rates and plasma volumes. the physiological responses of 10 subjects, 4. Step-function acceleration tolerance each serving as his own control, during and tolerance for sustained acceleration are alternate 10-day periods of immersion and more sensitive than the standard bioassay bed rest. Functional, diagnostic, and monitoring tests conducted before, during,

32 andafterthe 10-daytestingperiodswere volumeafter5 daysthandid bedrest,butthe usedto follow physiologicalchanges netlossafter10dayswasapproximatelythe producedby thesetwo analogsof null gravity samefor bothenvironments.Changesin andtoquantitativelycomparetheireffects. bloodvolumewereparallelto thoseof Fluid siliconewasusedastheimmersion plasmavolume. Immersionproducedan medium. elevatedurineflow, asevidencedby a Neitherimmersionnorbedrestproduced comparisonof urineoutputsin thetwo appreciablechangesin Master'stwo-steptest environmentsandby higherurineoutputs of exercisetolerance,restingoxygen thanfluid intakesduringimmersion.During consumption,tolerancetoaccelerationin the bedrestthesubjectsproducedamore gzdirection,visualandauditoryacuity,or in concentratedurine,bothwith respectto ECGandheartsoundrecordedduringtilt- individualelectrolytesandsoluteload. tabletesting.Therewerenosignificant Duringimmersionthedaily soluteload changesin microscopicorqualitativeanalysis excretedby thekidneywashigher,urine of theurinefor sugar,acetone,or protein; outputwaslarger,andosmolarclearancewas restingbloodpressure,temperature,heart, higher. andrespirationrate;bloodandurine Thesiliconefluid, immersiontanks, chemistriesor kidneyandliver functions. filtration,andcoolingequipmentmetthe No seriouscomplicationswerenotedin requirementsof theexperiment.Exceptfor anyof thesubjectsduringimmersionorbed two subjects,skinproblemsthatdeveloped rest. Neitheranalogproduceda free-water duringimmersionweretrivial. An effort to diuresis.Theresultsof thestudyconfirmthe relatetheoccurrenceof skinproblemsto detrimentaleffectsof prolongedimmersion bacteria,water,andcontaminationof the andbedrestonorthostatictoleranceand siliconewasinconclusive.Duringa 6-month extracellularfluid volume.Both analogs periodfollowing thestudy,thesubjectswere broughtaboutadeteriorationin the freeof abnormalphysicalsigns,symptoms, mechanismsessentialfor adequatecirculation andskin problems. in theerectposition. Thiswasshownby increasedincidenceof presyncopalreactions, 87. White PD, JW Nyberg, WJ by declinesin pulsepressure,andby White. increasedheartrateduringtilt-tabletesting. A comparative study of the Experimentalconditionsproducedreductions physiological effects of immersion in plasma,blood,andextracellularfluid and recumbency. volumes;declinesin maximumoxygen In: Proceedings of the Second consumption;andsomeimpairmentof Annual Biomedical Research posturalequilibrium. Lossesin bodyweight Conference. Houston, TX: NASA, wereprogressive,theaveragewas Mantled Spacecraft Center, 1966. approximately2%of initial weight. A p. 117-166. negativefree-waterclearancewasobtainedin Annotation all subjectsduringimmersionandbedrest. Purpose: Differentialeffectof thetwo The purpose of this study was to compare environmentsareseenin orthostatic the physiological effects of immersion and tolerance,fluid compartments,andrenal recumbency. Subjects were immersed in function. Theincidenceof pre-syncopal silicone fluid up to neck level for periods up reactionswashigherandoccurredearlier to 30 days. during immersionthanduringbedrest. Method: Heartrateswerehigherandpulsepressures Each subject was immersed to neck level werelowerduring immersionthanduring 24 hours per day for 10 days. bedrest. After 5 daysof immersionandbed Simultaneously 3 subjects were at absolute rest,theextracellularfluid decreasedby 3% bed rest (and second study reversed and2%,respectively.After 10days,thenet subjects), 8 subjects were at absolute bed decreasein fluid was5%duringimmersion rest, 6 subjects rode the short-radius and7% duringbedrest. Theconditionsof centrifuge (SRC) for a 20-min period four immersionproducedalargerlossin plasma

33 timesadayfor 80 min perdaypersubject. The salient generalizations derived from a Subjectsrodeat +3.5- 4 gzat thefeetand2 series of studies in which bed rest was used othersubjectsperformeda stepfunction as the analog of null gravity are presented. bioassayrideeveryotherday. The results of a pilot study to determine Results: the influence of periodic centrifugation on the All subjects riding the centrifuge four physiological disturbances associated with 41 times per day maintained tilt table tolerance. days of bed rest are reported in the fourth Changes in acceleration tolerance were seen study. The investigation was carried out in deconditioned subjects and it returned during 20 days of bed rest, and 16 days of toward normal with ambulation. bed rest with periodic rides on the centrifuge, Conclusion: followed by 5 days of bed rest, 1. SRC training can largely prevent centrifugation, and physical exercise. Major cardiovascular deconditioning from bed rest. findings of this study were (1) motion 2. There is a severe loss of g tolerance in sickness is not a problem for the well-trained subjects deconditioned with bed rest. individual when exposed to high angular rates of rotation and modest head or limb 88. White W J, JW Nyberg, PD movements, (2) deterioration produced by White, RH Grimes, LM recumbency in the ability to tolerate 900 head- Finney. up tilt for 20 min was largely alleviated by Biomedical potential of a centrifuge in periodic centrifugation as judged by syncopal an orbiting laboratory. episodes, (3) the three subjects receiving +4 Santa Monica, CA: Douglas Aircraft gz four times each day showed less lability in Co. Inc., Los Angeles Air Force blood pressure and heart rate during the tilt- Station, CA No. SSD-TDR-64-209, table tests than did the two subjects exposed Supplement, 1965. 120p. to +1 gc Authors' abstract The fifth study extended the results of the fourth study by increasing the integrated g- The results of several studies pertaining time from 0.5 and 2 g-hour to 3 g-hour, to manned orbital laboratories are reported. The first of these studies concerns the added approximately 700 kcal of exercise, and distributed the rides over a 24-hour consequence of heart-to-foot acceleration period as contrasted with the 8-hour schedule gradients for the measurement of tolerance to of the fourth study. A maintenance group of positive acceleration. A major finding of this study is that two modifications to the three subjects began riding the centrifuge ,0n the first day of bed rest and rode every day standard bioassay method--a low-intensity for 13 days. A therapy group of three central light and one gradual onset of subjects started riding the centrifuge after 17 acceleration to blackout--make it possible to days of bed rest and rode periodically for 6 measure tolerance in the presence of a 219% days. A control group of four subjects was heart-to-foot gradient with minimal cardiovascular stress. transported to and from the centrifuge, but was not rotated. The major finding of this The second was a parametric study of the study was that the use of periodic power requirements of a short radius centrifugation and exercise during bed rest centrifuge. The findings here were (1) empty tended to prevent deterioration, in the weight of the centrifuge is 155 lb, (2) peak maintenance group, of the mechanisms power consumption is 436 watts, (3) energy essential for circulatory control on the tilt consumption during a 7.5-min run at 4g is 5.85 Whr. table. The effects of centrifugation were indicated by lack of syncope in the The third study is an analysis of the maintenance group as compared with three errors resulting from use of the centrifuge to cases of syncope in the noncentrifuged determine body mass. The results of an error group. The effects of exercise were indicated reduction study and the experimental by heart rate responses during tilt. apparatus for verifying the two-radius As a result of these studies, the potential method are presented. of the short-radius centrifuge is presented and recommendations for future research are

34 made;andtheimpactonfuturemissionsis multifactorial approach which considers examined. individual +Gz tolerance levels.

89. Wiegman JF, LP Krock, RR 90. Wood EH, EF Lindberg, CF Burton, EM Forster. Code, EJ Baldes. Anaerobic power testing and +Gz Effect of partial immersion in water endurance. on response of healthy men to Aviation, Space, and Environmental headward acceleration. Medicine 60:512, 1989. (Abstract). Journal of Applied Physiology Authors' Abstract 18:1171-1179, 1963. Introduction: Authors' Abstract Performance of the L- 1 and M- 1 straining Protection against the effects of headward maneuvers, used during high sustained +Gz, acceleration afforded by immersion in water has been described as anaerobic work. has been assayed in the human centrifuge on Therefore, the present study examines the 15 trained subjects. Immersion in water to relationship between anaerobic abilities and the xyphoid afforded an average protection of +Gz endurance. 1.1 + 0.1 G for vision and ear opacity and of Methods: 1.6 + 0.2 G for ear pulse and heart rate. The Wingate cycle ergometer test (WAT) Deeper immersion, to the level of the third rib at the sternum increased the protection to 1.8 was employed to assess upper and lower body capacity for short-term exhaustive + 0.1 G for vision and ear opacity and to 2.8 exercise in 8 subjects. Performance indices + 0.2 G for ear pulse and heart rate. The (measured 3 times) include: peak power for a protection afforded the various physiologic 5-sec period; 30-sec mean power (MP, an variables increased with the magnitude of index of anaerobic capacity); and percent acceleration tested. Protection against loss of fatigue. Acceleration was measured by consciousness may be greater than protection duration in seconds, on 2 occasions, for a against blackout and is probably similar to the simulated aerial combat maneuver (SACM) protection afforded the ear pulse and heart rate. The cardiovascular reactions produced profile which alternates 4.5-7 G (15 sec each) until exhaustion. Heart rate was collected by headward acceleration are qualitatively similar with and without water immersion. online and blood lactates sampled at rest and 3, 6 and 8 rain post-WAT and post-SACM. This finding does not support the concept that Results: impediment to venous return is the primary determinant of man's tolerance to headward SACM duration is not significantly acceleration. Visual symptoms occurred at correlated with WAT power outputs or blood lactates post-SACM in five subjects tested greater amplitudes of ear pulse, and thus far. However, a correlation coefficient presumably also at greater blood pressures at head level, during water immersion than exists between SACM time and highest during control runs. observed blood lactates following the lower body WAT (r = .93). The 2 subjects with 91. Zborovskaya BI. the highest single SACM times (391 sec), Use of short-arm centrifuge to exhibit contrasting lower body WAT MPs of 495 and 825 W; max heart rates during prevent deconditioning when immersed in water (according to H- SACM of 158 and 178 bpm; and peak blood reflex). lactates post-SACM of 3.61 and 5.91 mmol/L, respectively. Kosmicheskaya Biologiya i Conclusions: Aviakosmicheskaya Meditsina 13:78-79, 1979. Some individuals may work at a Author's Abstract submaximal intensity, not associated with anaerobic metabolism, during the 4.5-7 G A study was made of the possibility of SACM. The role of anaerobic power in +Gz using periodic rotation on a short-arm endurance should be further evaluated in a centrifuge (SAC) as a means of preventing the adverse effects of immersion.

35 Eachsubjectwassubmittedto +3Gzafter pureimmersionandimmersioncombined with periodicrotationon aSAC, where accelerationsof +0.8Gz,+l.2Gz or 1.6Gz weregeneratedfor 60 min twice aday(first series)andfor 40 min 3 timesaday (second series). In 76%of thecasestherewasearly recoveryof H-reflexamplitude( lS'_3d min of aftereffect)with exposureto +3Gz after immersioncombinedwith SACwhenusing G forcesof +1.2Gz for 40 min 3 timesa day,and62%for +1.6Gz for 60 min twicea day.

36 ADDITIONAL SELECTED BIBLIOGRAPHY

Antonutto G, C Capeili, PE Life in Spacecraft, 1968. p. 123-131. diPrampero (NASA TT F-11,401, 1967). Pedalling in space as a countermeasure to microgravity Meehan JP and HI Jacobs. deonditioning. Relation of several physiological Microgravity Q 1:93-101, 1991. parameters to positive G tolerance. Los Angeles, CA: Universi_, of Balldin UI. Southern California, School of Physical training and +Gz tolerance. Medicine, Wright Air Development Aviation, Space, and Environmental Center Technical Report No. 58- Medicine 55:991-992, 1984. 665, 1959. lip.

Bjurstedt H, O Eiken. Murthy G, DE Watnepaugh, RE Graded ischemia in exercise human Ballard, AR Hargens. skeletal muscles: Methods and Supine exercise during lower body applications. negative pressure effectively News in Physiological Sciences simulates upright exercise in normal 10:193-197, 1995. gravity. Journal of Applied Physiology Burton RR. 76:2742-2748, 1994. A human-use centrifuge for space

stations: Proposed ground-based Norsk eo studies. Gravitational stress and volume Aviation, Space, and Environmental regulation. Medicine 59:579-582, 1988. Clinical Physiology 12:505-526, 1992. Greenleaf JE. Importance of fluid homeostasis for Nyberg JW, RH Grimes, WJ White. optimal adaptation to exercise and Consequence of heart-to-foot environmental stress: Acceleration. acceleration gradient for tolerance to In: Perspectives in Exercise positive acceleration. Science and Sports Medicine. Vol. Aerospace Medicine 37:665-668, 3: Fluid Homeostasis During 1966. Exercise, edited by CV Gisolfi, DR Lamb. Carmel, IN: Benchmark Piemme TE, AS Hyde, M McCally, G Press, Inc., 1990. p. 309-346. Potor, Jr. Human tolerance to Gz 100 per cent Kotovskaya AR, RA Vartbaronov, SF gradient spin. Simpura. Aerospace Medicine 37:16-21, Izmeneniye perenosimosti 1996. chelovekom poperechnykh peregruzok posle gipodinamii Shumate WH, SD Leverett, SJ razlichnoy prodolzhitel'nosti. Shubrooks, CK LaPinta. (Changes in the tolerance of man to Physiological effects of prolonged transverse accelerations following positive (+Gz) acceleration following hypodynamia of varying duration). one and seven days bedrest. Proceedings of the 18th Congress of In: Physiological Effects of the International Astronautical Prolonged Positive +Gz Federation, edited by M Kung. Acceleration following One and Warsaw: Pergamon Press & PWN- Seven Days Bedrest, edited by WH Polish Scientific Publishers, Vol 4, Shumate. Houston, TX: NASA

45 MannedSpacecraftCenter,Chapt.1, Watenpaugh DE, RE Ballard, MS 1971.p.l-13. Stout, G Murthy, RT Whalen, AR Hargens. von Beckh HJ. Dynamic leg exercise improves Flight experiments about human tolerance to lower body negative reactions to accelerations which are pressure. followed or preceded by Aviation, Space, and Environmental weightlessness. Medicine 65:412-418, 1994. In: Proceedings of the IX International Astronautical Congress, Vol. 2, 1958. p.507-525.

46 Author Index (numbers refer to abstract number)

Akhrem-Akhremovich RM: 35 Aleksandrova EA: 72 Finney LM: 85, 86, 88 Andersen HT: 3 Forster EM: 17, 89 Andreyeva VG: 37 Annis J: 71 Gale RR: 18 Antonutto G: 1 Gardiner IDR: 10 Armbruster R: 26 Gavrilova LN: 18 Asyamolov BF: 2, 40 Georgiyevskiy VS: 19, 35 Augerson WS: 5 Gogolev KI: 20, 72 Goldenrath WL: 64 Backhausen F: 42, Goldwater DJ: 21, 22, 58, 70 Baldes EJ: 90 Golovkina OL: 23 Balldin UI: 3, 4, 68, 69, 77 Grave C: 8 Baranova BP: 54 Greenleaf JE: 24, 25, 26, 27, 28, 78 Beckman MC: 5 Grigoriev AI: (Gregor'yev AI): 29, 30, 73 Benevolenskaya TV: 60 Grimes RH: 88 Benson VG: 5 Grunbaum BW: 71 Bernauer EM: 14, 15, 16, 26, 27, 28 Bjurstedt H: 6 Haines RF: 26, 28 Bodarenko RA: 2 Hannah K: 32 Boglevskaya NM: 54 Henry JP: 59 Boykova OI: 60 Hjort H: 77 Brock PJ: 24, 25 Hoffler GW: 31 Brtiner H: 42, 44, 45, 46, 47 Houghton JO: 32 Brunjes S: 59 Hyatt KH: 33 Bulbulian R: 7 Burton RR: 12, 14, 15, 16, 89 Jacobson LB: 33 Johnson PC: 55 Chambers RM: 5 Johnson RL: 31 Chase GA: 8 Jorgenson H: 10 Chelnokova NA: 66 Jovy D: 42, 45 Cherepakhin MA: 9, 35 Juhos L: 78 Chertovskikh YeA: 54 Clark WG: 10 Kakurin LI: 34, 35 Coburn KR: 5 Kaliberdin AV: 2 Code CF: 90 Kamenskii YuN: 36, 37 Convertino VA: 21, 22, 58 Katkovskiy BS: 35, 38 Cooper KH: 11 Keil LC: 39 Crisman RP: 12, 63 Khapilov NV: 40 Khomenko MN: 13 Davis GL: 27 Khudyakova MA: 41, 73 DeForest RE: 5 Klein KE: 42, 44, 45, 46, 47, 48 de Vries H: 59 Kokova NI: 49 di Prampero PE: 1 Kollias J: 27 Dlusskaya IG: 13 Korotayev MM: 61 Dobronravova NN: 61 Kotovskaya AR: 35, 50, 51, 52, 53 Dolkas D: 71 Kotov NN: 40 Driscoll TB: 55 Kozar MI: 61 Kozlova VG: 74 Eichhorn J: 42, 44 Krauhs JM: 56 Elizarov SYu: 2 Krikum IS: 18 Elizondo R: 25 Krock LP: 89 Ellis S: 39 Krupina TN: 54 Epperson WL: 14, 15 16 Kudrin KA: 74

47 KudrovaRV: 66 SandierH: 21, 26,28, 33, 56, 58,64, 70, Kuklinski P:48 71 KuronenP: 4, 68, 69 SavilovaAA: 60 Kuz'min MP: 60 Schlhalk_iuserKL: 44 KuznetsovMI: 66 SchotteJ:42,44 SciaraffaD: 24,25 LeachCS: 55,56 SenkevichYuA: 35 LeverettJr. SD: 11,62 ShamrovPG:35 LindbergEF:90 ShilovVM: 61 LinnarssonD: 1 ShubrooksSJ: 57 Lobzin PP:66 Shul'zhenko,YeB (EB): 30, 36, 37,41, 72, LohrbauerLA: 57 73, 74,80, 81 Ludwig DA: 58 SimpuraSF:35,51, 52,53 Solov'yevaSN: 60 MatsnevEI: 54 SpenceDW: 75 McBride DK: 32 StaleyRW: 28 McCallyM: 57 StinnettHO: 27 Mclntyre AK: 10 SundbergCJ: 1 MeehanJP:59 SuvorovPM: 76 MeyerLG: 63 SvenssonE: 4 MikhaylovVM: 19 SyzrantsevYuK: 66 Mikhaylovskiy GP:60,61 Miller PB: 62 TerpilovskiyAM: 66 MorseJT: 26 TeschPA: 3, 68,69,77 MukharlyamovNM: 35 Tizul AYa:54 MurdochDM: 63 TsiganovaNI: 61 Myhre K: 3 UdalovYuF: 66 NewsomBD: 64,71 UlyatovsiyNV: 2 NybergJW: 85, 86, 87,88 UstyushinBV: 18 OvechkinVG: 18 vanBeaumontW: 26,28,78 VanyushinaYuV: 35 PaceN: 71 VarbaronovRA: 35 PanchenkoVS: 2, 40 VartbaronovRA: 52,53 PanferovaNYe: 35 VartbaronovRV: 51 ParnellMJ: 65, 84 Vernikos-DanellisJ: 56 PetrovaTA: 60 Vil-Vilyams IF: 72,73,79, 80,81 PetrovykhVA: 66 Voigt ED:44,46 PetuknovBN: 67 VogtL: 42,45,47 PlokhovaVG: 2, 74 VoroninLI: 2 PoleseA: 25 PopovIG: 66 WebbP:71 PurakhinYuN: 67 WegmannHM: 42,44,45, 46,47, 48 PushkarYuT: 35 WesselJA: 82 WhinneryJE: 17,65, 83,84 RomanovaIA: 66 WhitePD: 85,86,87,88 RosenhamerG: 6 WhiteWJ: 85,86,87,88 RositanoSA: 70 WiegmanJF:89 RowellLB: 8 WigertzO: 6 RuskoH: 4, 68, 69 Wiley RL: 57 WilhelmsenU: 3 SaganL: 26 WinterWR: 64 WoodEH: 90

48 Author Index (numbers refer to abstract number)

Wolthuis RA: 31

Yakovleva IYa: 60, 61 Yarov AS: 2, 74 Yelkin PA: 18 Yelkina LG: 18 Young HL: 28, 78 Yusken JW: 28

Zborovskaya BI: 91

49

Keyword Index (numbers refer to abstract number)

Abdominal muscle training: 3 shifts: 27, 29, 30, 73 Acceleration tolerance: 2, 5, 7, 9, 10, 11, 12, supplements: 49 13, 14, 15, 17, 19, 21, 22, 24, 25, Flexor muscles of abdomen and hip: 3 27, 30, 31, 32, 35, 39, 40, 42, 44, Formed elements: 61 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 64, Gas exchange: 23 65, 67, 70, 71, 72, 73, 74, 75, 76, Gauer-Henry reflex: 5 78, 80, 82, 87, 88, 90 G-tolerance: 2, 3, 16, 17, 24, 26, 27, 28, Aerobic 32, 33, 39, 44, 45, 48, 49, 51, 52, fitness: 12, 17, 46 53, 55, 57, 59, 60, 62, 63, 64, 65, training: 22, 84 68, 69, 70, 72, 73, 74, 75, 77, 78, Age: 56, 58, 70 79, 81, 83, 86, 89 Anaerobic power: 89 Antigravity: 2 H-reflex: 91 Arterial lactates: 6 Head-down tilt: 2 Artificial gravity: 1 Heart rate: 4, 6, 8, 11, 13, 28, 44, 45, 47, 48, 49, 51, 53, 57, 62, 70, 71, 73, Bed rest: 7, 9, 19, 21, 26, 27, 28, 31, 34, 74, 79, 80, 81, 82, 84, 85, 87 38, 39,50, 51, 52, 53, 54, 55, 56, Hematocrit: 10 59, 60, 61, 62, 67, 70, 71, 78, 85, Human centrifuge: 1, 3, 8, 18, 23, 37, 41 86, 87, 88 Hypokinesia: 2, 9, 18, 19, 34, 35, 40, 54, Blood 60, 61, 67, 74, 76 clotting: 41 Hypoventillation: 8 pressure: 8, 13, 28, 45, 47, 49, 51, Hypoxia: 44, 46, 47 57, 58, 70, 90, 91 volume: 13 Immersion: 5, 20, 30, 36, 37, 41, 48, 49, Body weight: 28, 58 50, 72, 73, 74, 79, 80, 81, 86, 87, Breathing: 36, 37 90, 91 Immunity: 34, 61 Cardiovascular Intra-abdominal pressure: 3 deconditioning: 1 Isometric training: 3, 26, 68, 69, 75 response: 17, 50, 52, 60, 62, 65, 71, Isotonic exercise: 6, 9, 26 73, 80 Circulation: 19, 40, 60, 80 Knee extensor muscles: 3, 77

Diet: 9, 66 Lean body mass: 11 Diuresis: 5 Lower body negative pressure (LBNP): 31, Dynamic endurance: 3 33, 48, 56, 71, 76, 85

Electrocardiogram: 2 Manned space flights: 29 Electrolyte responses: 25, 27, 29, 30 Maximal peak torque: 3 Endocrine responses: 25, 56, 71 Metabolism: 38 Endurance capacity: 11, 48, 65, 68 Muscle: Environment cool/hot: 24 endurance: 3, 67, 75 Exercise: strength: 14 anaerobic: 12 Musculo-skeletal deconditioning: 1 heat acclimation: 24 Myogram: 2 training: 4, 12, 23, 52, 54, 63 Nervous system: 54, 64 Fat: 11, 58, 65, 84 Neuromuscular adaptation: 77 Fitness test: 82 Fluid: Orthostatic tolerance: 31, 35, 45, 47, 48, 58, loss: 10 79, 87 retention: 49

51 Oxygenuptake:6, 7, 11,14,21, 33,44,45, Salt supplements: 49 46, 48, 58, 65, 69, 78, 84, 87 Schneider test: 46 Short-radius centrifuge: 20, 23, 79, 81, 87, Performancecapacities:8,45,69 88, 91 Peripheralintracranialcirculation:18 Shuttle flight: 21, 22, 33 Photoplethysmography:2 Simulated aerial combat maneuver: 4, 7, 14, Physical: 15, 16, 77 conditioning: 11, 15,42,43,48 Specific weight training: 16 training:7, 24,45 Static endurance: 3 Plasma: Strength training: 68, 69, 77 protein:10 Submaximal intensity: 89 reninactivity:39 Syncope: 32, 48, 83 vasopressin:39 volume:27, 58,78,85 Thyroid function: 55 Psychomotorperformance:59 Tilt test: 13, 33, 42, 43, 45, 48, 88 Pulmonaryvolumes:5 Training: 44, 46 Transcapillary exchange: 20 Rateof perceivedexertion (RPE): 4 Treadmill: 8, 69 Rehydration: 28 Renal function: 30 Valsalva maneuvers: 51 Respiration: 50, 51, 52, 53, 71 Veloergometer: 79 Running: 63, 82 Vestibular tolerance: 1

Water loading: 13 Weight: 11, 45, 85 Weight lifting: 63, 82 Work: capacity: 8 load: 6

52

Form Approved REPORT DOCUMENTATION PAGE gumNo.0704-0,80

Public reporting burden for thiscollection ol informationis estimated to average 1 hour per response. _nctuding the time for reviewing instructions,searchingexisting data sources, gathenng and maintaining the data needed, and completingand reviewingthe collectionof informal=of, Send commentsregardingthis burdenestimateor any other aspect of this collectionOf mformahon, including suggest=onefor reducingthis burden, to WashingtonHeadquartersServices, Directoratefor information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204. Arlington,VA 22202.4302, andto the Office of Management and Budget, PaperworkReductionProiect(0704-0188), Washinglon, DC 20503 1. AGENCY USE ONLY (Leave blank) _2. REPORT DATE 3. REPORT TYPE AND DATES COVERED I October 1997 Technical Memorandum 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Acceleration Tolerance: Effect of Exercise and Acceleration Training; Bed-Rest and Weightlessness Deconditioning A Compendium of Research (1950-1996) 199-97-62-13 6. AUTHOR(S) J. L. Chou, M. A. McKenzie, N. J. Stad, P.R. Barnes, C. G. R. Jackson, F. Ghiasvand, and J. E. Greenleaf

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Ames Research Center Moffett Field, CA 94035-1000 A-978165

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY REPORT NUMBER

National Aeronautics and Space Administration NASA TM-112214 Washington, DC 20546-0001

11. SUPPLEMENTARY NOTES Point of Contact: Author, Ames Research Center, MS 239- l, Moffett Field, CA 94035-1000; (415) 604-6604

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Unclassified -- Unlimited Subject Category 52

13. ABSTRACT (Maximum 200 words)

This compendium includes abstracts and annotations of clinical observations and of more basic studies involving physiological mechanisms concerning interaction of acceleration, training and deconditioning. If the author's abstract or summary was appropriate, it was included. In other cases a more detailed annotation of the paper was prepared under the subheadings Purpose, Methods, Results, and Conclusions. Author and keyword indices are provided, plus an additional selected bibliography of related work and of those papers received after the volume was prepared for publication. This volume includes material published from 1950-1996.

t4. SUBJECT TERMS 15. NUMBER OF PAGES 56 Acceleration, Exercise, Deconditioning 16. PRICE CODE A04

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE OF ABSTRACT Unclassified Unclassified

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prelcnbed by ANSI Sial Z3g-18 298-102