Effects of Whole-Body Vibration Exercise Training on Aortic Wave Reﬂection and Muscle Strength in Postmenopausal Women with Prehypertension and Hypertension

ORIGINAL ARTICLE Effects of whole-body vibration exercise training on aortic wave reﬂection and muscle strength in postmenopausal women with prehypertension and hypertension

A Figueroa, R Kalfon, TA Madzima and A Wong

Increased wave reflection (augmented pressure (AP) and augmentation index (AIx)) and reduced muscle strength may increase cardiovascular risk in postmenopausal women. We evaluated the effects of whole-body vibration exercise training (WBVET) on aortic haemodynamics and leg muscle strength. Twenty-eight postmenopausal women (age, 56±3 years; brachial systolic blood pressure (SBP) 138±12 mm Hg; body mass index, 33.9±3.7 kg m À 2) were randomized to 6 weeks of WBVET (n ¼ 15) or no-exercise control groups. Aortic SBP, diastolic blood pressure (DBP), pulse pressure (PP), AP, AIx, tension time index (TTI, myocardial oxygen demand) and leg press muscle strength were measured before and after 6 weeks. WBVET significantly (Po0.05) decreased aortic SBP (B10 mm Hg), DBP (B5 mm Hg), PP (B5 mm Hg), AP (B5 mm Hg), AIx (B10%) and TTI (B311 mm Hg s per minute), while increased muscle strength (B9%) compared with no changes after control. Changes in AP and leg muscle strength were correlated (r ¼À0.58, P ¼ 0.02). Our data demonstrated that WBVET reduced pressure wave reflection magnitude and aortic blood pressure in postmenopausal women with prehypertension or hypertension. Our study suggests that WBVET may decrease cardiovascular risk in postmenopausal women by improving wave reflection and muscle strength.

Journal of Human Hypertension (2014) 28, 118–122; doi:10.1038/jhh.2013.59; published online 4 July 2013 Keywords: obesity; exercise training; wave reﬂection; muscle strength

INTRODUCTION postmenopausal women.18,19 Recently, we found a decrease in As a result of ageing and obesity,1 impaired vasomotor aortic SBP and AIx following 6 weeks of WBV training in young 16 tone increases pressure wave reflection from peripheral arteries normotensive overweight and obese women, but AP was 20 to the aorta causing augmented pressure (AP).2 AP is the main not analysed. Acute WBV has been shown to decrease AP and 21 determinant of increased aortic systolic blood pressure (SBP), induce arterial vasodilation in the exercised legs. Similarly, acute pulse pressure (PP) and augmentation index (AIx), and is greater in and short-term administration of vasodilatory drugs can attenuate older women than in men.3,4 This high pressure wave reflection AP by reducing wave reflection magnitude from peripheral 9,22,23 predisposes women to myocardial ischemia due to increased arteries to the aorta. Therefore, WBV training would reduce oxygen demand.2 AP and AIx through a reduction in wave reflection magnitude. In addition to arterial ageing, there is a greater loss of leg The purpose of this study was to examine whether WBV training muscle strength than muscle mass in older adults.5 Interestingly, improves aortic blood pressure (BP), wave reflection and muscle leg muscle strength loss, but not muscle mass, has been strength in obese postmenopausal women with prehypertension associated with mortality in older individuals.6 It appears that or hypertension. We hypothesized that WBV training would high muscle strength has a protective effect on all-cause mortality improve aortic haemodynamics and muscle strength and the in men with hypertension.7 A recent cross-sectional study improvements will be inversely related. reported an inverse relationship between explosive leg muscle strength and AIx in older adults.8 Because the age-related increase in wave reflection and subsequent risk for heart failure is greater in women than in men,4,9 strategies that counteract or improve MATERIALS AND METHODS the negative consequences of wave reflection and muscle Study participants weakness in older women are needed. Thirty women volunteered for this randomized parallel design Although the effectiveness of moderate to high-intensity study. Participants were postmenopausal (41 year without menstrua- 24 À 2 resistance exercise training for improving muscle strength in tion), overweight or obese (body mass index (BMI)425 kg m ), middle-aged and postmenopausal women is well recognized,10–12 prehypertensives or stage-1 hypertensives (SBP4120 mm Hg), and sedentary ( 60 min of regular exercise training).25 Participants were resistance exercise training may cause either a negative13 or no o 11,12,14,15 non-smokers, free of apparent cardiovascular diseases as assessed by impact on AIx. Alternatively, whole-body vibration medical history and not taking vasoactive medication or hormone therapy. exercise (WBV) training has shown to be a potential rehabili- Participants were excluded if they had diabetes, joint prosthetic devices, tation modality for muscular and arterial function. WBV training recent thrombosis or wounds in the legs. All participants gave written has proven to improve muscle strength in young16,17 and informed consent. The study protocol was approved by The Florida State

Department of Nutrition, Food and Exercise Sciences, The Florida State University, Tallahassee, FL, USA. Correspondence: Dr A Figueroa, Department of Nutrition, Food and Exercise Sciences, The Florida State University, 120 Convocation Way, Tallahasseee, FL 32306-1493, USA. E-mail: afi[email protected] Received 4 March 2013; revised 24 May 2013; accepted 3 June 2013; published online 4 July 2013 Augmented pressure and muscle strength A Figueroa et al 119 University Human Subject Committee and registered in ClinicalTrials.gov Whole-body vibration exercise training (NCT01741779). Participants underwent three supervised training sessions per week separated by at least 48 h for 6 weeks. The WBV training included leg Study design exercises standing on a WBV platform (Power Plate pro5 AIRdaptive, Northbrook, IL, USA). Exercises consisted of both dynamic and static for Women were randomly assigned to either 6 weeks of WBV training (n ¼ 15) semi-squats and lunges with a 1201 knee angle (considering 1801 as full or non-exercising control group (n ¼ 15) (Figure 1). Participants reported to knee extension), squats with a 901 knee angle and calf-raises. The dynamic the laboratory following an overnight fast and refrained from caffeine and exercises were performed with slow movements at a rate of 2 s for the alcohol for 24 h or moderate-to-intense physical activity for 48–72 h before concentric phase and 3 s for the eccentric phase. The vibration intensity each visit. Haemodynamics were assessed after 15 min in the supine was progressed by increasing the frequency (25–35 Hz) and amplitude position in a quiet temperature-controlled room (23±1 1C). Thereafter, (1 mm). The duration (30–45 s) and number of the sets (1–2) was body composition and leg muscle strength were assessed. All measure- progressively increased, while the interest rest period was maintained at ments were repeated after the 6-week intervention period. After WBV 60 s. The selected training protocol is similar to that previously used in training, cardiovascular testing was performed at least 24 h after the last postmenopausal and obese women.16,18 WBV session. Women were advised not to change their regular lifestyles during the study. The control group was instructed to refrain from any mode of structured exercise training. Statistical analyses Pulse wave analysis All variables were normally distributed (Shapiro–Wilk test). Based on previous data,16 it was calculated that 14 participants per group would The average of two measurements of brachial SBP and diastolic blood provide 80% power (two-sided a ¼ 0.05) to detect a 6% difference in AIx. pressure (DBP) was used to calibrate radial waveforms obtained in Unpaired t-test was used to identify possible group differences at baseline. duplicate from a 10-s epoch using a high-fidelity tonometer (SPT-301B; The effect of the intervention over time was evaluated by a 2 Â 2 analysis Millar Instruments, Houston, TX, USA). Aortic pressure waveforms were of variance with repeated measurements (group (control vs WBV) Â time derived using a generalized validated transfer function (SphygmoCor, (before and after 6 weeks)). When a significant group-by-time interaction AtCor Medical, Sydney, Australia). PP was calculated as SBP-DBP. AP is the and/or time effect was identified, post hoc comparisons were made with difference between the second (P2) and first systolic peak (P1). The AIx was paired t-tests to detect within-group differences across time. Pearson’s calculated as the AP expressed as a percentage of aortic PP ((P2 À P1)/ correlations were used to analyse the relationship between changes in PP Â 100). AIx normalized for a heart rate of 75 beats per minute (AIx@75) wave reflection and %strength. A value of P 0.05 was accepted as was also calculated. TTI, defined as the systolic pressure integral as a o statistically significant. Variables are presented as mean±s.d. function of time per minute, was considered as a measure of myocardial oxygen demand.26 The average of two measurements of aortic haemodynamic with high quality (operator index X80%) was used in the analysis. In our laboratory, the intraclass correlation coefficient for RESULTS resting aortic SBP, AP and AIx taken on 2 separate days is p0.95. Two participants in the control group dropped out for personal Leg muscle strength reasons. Data are presented for 15 and 13 participants in the WBV and control groups, respectively (Figure 1). Time since menopause Leg muscle strength was measured by the eight-repetition maximum ± (8RM) test27 using variable resistance equipment for the leg press exercise did not differ between the WBV (5.7 2.2 years (range: 3–10 (MedX Corp., Ocala, FL, USA). The highest weight moved eight times years)) and control (5.9±2.1 years (range: 3–9 years)) group. through the full range of motion using a good form was considered as the Attendance to the exercise sessions, addressed from training logs, 8RM. Changes in muscle strength are presented as percentage of the was 498%. baseline 8RM (%strength).

Body composition Participant characteristics Height was measured to the nearest 0.5 cm using a stadiometer and body Table 1 shows participant characteristics, body composition, weight was measured to the nearest 0.1 kg using a seca scale (Sunbeam muscle strength and brachial BP before and after the interven- 2 Products Inc., Boca Raton, FL, USA). BMI was calculated as kg m À . Body fat tions. There were no significant differences in these parameters at percentage (%) and bilateral arm and leg lean mass were determined from baseline. A significant group-by-time interaction (Po0.05) was whole-body dual-energy x-ray absorptiometry scans (GE Lunar DPX-IQ, detected for leg muscle strength and brachial BP. The 8RM Madison, WI, USA). increased after WBV training compared with no change after control. Brachial SBP and DBP significantly (Po0.01) decreased after WBV training compared with no changes after control. Body weight, BMI, body fat% and lean mass of arms and legs did not Baseline assessment Randomization (n = 30) change in both groups.

Aortic haemodynamics Table 2 shows haemodynamic variables before and after 6 weeks Control WBV training of WBV training and control. There were no group differences in (n =15) (n =15) any variable at baseline. There were group-by-time interactions (Po0.05) for aortic SBP, DBP, PP, AP, AIx, AIx@75, P2 and TTI. Aortic SBP, DBP, PP, AP (Figure 2a), AIx (Figure 2b), AIx@75, P2 and TTI Withdrawn signiﬁcantly (Po0.01) decreased after WBV training, but no (n = 2) signiﬁcant changes occurred after control.

Complete study Complete study Correlations between wave reﬂection and muscle strength (n =13) (n =15) The changes in %strength were correlated with changes in AP (r ¼À0.58, P ¼ 0.024) (Figure 3), but not with changes in AIx Figure 1. Flow chart of the study design. (r ¼À0.54, P ¼ 0.058).

& 2014 Macmillan Publishers Limited Journal of Human Hypertension (2014) 118 – 122 Augmented pressure and muscle strength A Figueroa et al 120 Table 1. Participant characteristics before and after the 6-week interventions

Variable Control (n ¼ 13) WBV training (n ¼ 15)

Before After P-valuea Before After P-valuea P-valueb

Age, years 56±3 ÀÀ56±3 ÀÀÀ Height, m 1.63±0.06 ÀÀ1.61±0.09 ÀÀÀ Body weight, kg 93.4±12.4 92.7±12.4 0.099 85.1±11 84.6±10 0.334 0.777 BMI, kg m À 2 35.2±3.4 35±3.3 0.102 32.8±3.6 32.6±3.4 0.362 0.765 Brachial SBP, mm Hg 138±13 138±11 0.375 138±13 128±11 0.001 0.001 Brachial DBP, mm Hg 79±880±7 0.804 81±975±8 0.008 0.015 Body fat, % 50.8±5.1 50.9±5 0.779 49.0±4 49.3±3.7 0.318 0.543 Arm lean mass, kg 5.0±0.9 5.0±0.8 0.242 4.5±0.7 4.4±0.7 0.082 0.655 Leg lean mass, kg 15.2±2 15.2±1.8 0.699 14.2±0.1 14.2±0.1 0.858 0.921 Leg strength, kg 231±68 232±68 0.372 228±68 247±70 0.0001 0.0001 Abbreviations: BMI, body mass index; DBP, diastolic blood pressure; SBP, systolic blood pressure; WBV, whole-body vibration exercise. Data are mean±s.d. aWithin-group difference analysed by paired t-test. bANOVA group Â time interaction.

Table 2. Haemodynamic parameters before and after the 6-week interventions

Variable Control (n ¼ 13) WBV training (n ¼ 15)

Before After P-valuea Before After P-valuea P-valueb

Aortic SBP, mm Hg 131±14 130±12 0.481 131±13 120±10 0.001 0.001 Aortic DBP, mm Hg 82±682±5 1.000 82±976±7 0.007 0.015 Aortic PP, mm Hg 47±846±7 0.593 49±744±5 0.002 0.007 AP, mm Hg 18±717±5 0.200 21±716±6 0.001 0.006 Aortic AIx, % 35±834±9 0.436 38±831±7 0.008 0.027 Aortic AIx@75, % 31±730±9 0.558 35±827±7 0.002 0.015 Aortic P1, mm Hg 111±7 112±8 0.417 109±10 105±9 0.066 0.060 Aortic P2, mm Hg 130±11 127±9 0.395 131±13 121±10 0.001 0.004 TTI, mm Hg s per minute 2653±354 2636±264 0.681 2804±313 2493±356 0.001 0.001 DTI, mm Hg s per minute 3722±539 3787±649 0.159 3393±372 3219±242 0.084 0.055 Heart rate, beats per minute 66±567±7 0.320 67±666±6 0.421 0.217 Abbreviations: AIx, augmentation index; AIx@75, AIx adjusted to 75 beats per minute; AP, augmented pressure; DBP, diastolic blood pressure; DTI, diastolic tension time index; PP, pulse pressure; P1; ﬁrst systolic peak; P2, second systolic peak; SBP, systolic blood pressure; TTI, systolic tension time index. Data are mean±s.d. aWithin-group difference analysed by paired t-test. bANOVA group Â time interaction.

DISCUSSION and PP ( À 5 mm Hg) after WBV training. Thus, WBV training may The present study examined the impact of WBV training on reduce cardiovascular risk in postmenopausal women. pressure wave reflection in obese postmenopausal women with In the present study, AP ( À 5.1 mm Hg) and magnitude of the high BP. The main findings were that 6 weeks of WBV training reflected wave (P2) were attenuated with WBV training, while decreased wave reflection magnitude and aortic BP. In addition, the first systolic peak (P1) was not affected. The increase in AP in the relative increase in leg muscle strength was correlated with middle-aged adults is attributed to an increase in wave reflection 3,29 the decrease in AP. magnitude. AP increases by B6.7 mm Hg in middle-aged Pressure wave reflection can be examined as the difference women over a 10-year period.9 The age-related increase in between the second and first systolic peak relative to aortic PP aortic haemodynamics in women may be induced by reduced (AIx) or in absolute amount of AP. The increased AIx observed in nitric oxide-dependent vasodilation as acute9 and 4 weeks22 our participants before WBV training may be explained by age, administration of nitrovasodilators decrease AP by 7.5–9 mm Hg. female sex and obesity.1,3,4 The reduction in AIx ( À 10%) found With attenuated magnitude of the reflected wave due to following WBV training in the present study is in agreement with peripheral artery vasodilation, aortic SBP decreases, and thereby our previous report ( À 8%) in young normotensive women.16 AP and left ventricular afterload.22,23 Our present study has shown However, the magnitude of the decrease in AIx appears to be that WBV training have favourable effects on aortic haemo- greater in older women with prehypertension and hypertension. dynamics in postmenopausal women with prehypertension and In middle-aged adults, an increase in the reflected wave stage-1 hypertension, which would be attributed to the magnitude augments aortic SBP and PP, which in turn, increases vasodilatory effect of WBV on leg muscular arteries.21 the AIx.3,28 This age-related increase in wave reflection, which is A negative relationship between radial AIx and explosive higher in women than in men,3,4,29 may contribute to the strength has been reported in older adults.8 Because AP development of left ventricular diastolic dysfunction4 and progressively increases with ageing, while AIx may decrease coronary artery disease.30 A recent meta-analysis revealed that with older age,3,9 AP may be a more accurate marker of wave increases in AIx and aortic BP (SBP and PP) by 10% and 10 mm Hg reflection than AIx in middle-aged and older adults.32 We would increase the risk for cardiovascular events by 31.8, 8.8 and observed an increase in leg muscle strength following WBV 13.7%, respectively.31 In the present study, concurrently with the training with no significant increase in lean mass. Strength gain reduction in AIx, we noted decreases in aortic SBP ( À 11 mm Hg) is a well-documented finding following WBV training.16,18,19

Journal of Human Hypertension (2014) 118 – 122 & 2014 Macmillan Publishers Limited Augmented pressure and muscle strength A Figueroa et al 121 associated with prevalent coronary artery disease via reduced myocardial perfusion.32 In the current study, the reduction in aortic AP may have influenced the decrease in TTI, a marker of myocardial oxygen demand.26 Of note, reductions in AIx and AP have not been associated with strength gains following resistance exercise training in older adults.12,14,34 Our study has some limitations. Our participants were obese postmenopausal women with prehypertension or stage-1 hypertension and the observed findings may be influenced by adiposity, age, sex and BP category. Furthermore, blood gonadotropins and sex hormone levels were not measured and the postmenopausal status of our participants was self-reported. Another limitation of the present study may be the lack of an exercise no-WBV group. However, exercise without WBV does not induce an acute decrease in AIx, but an increase.20 In summary, we have shown that WBV training reduces wave reflection magnitude, aortic BP while increases leg muscle strength in obese postmenopausal women with prehypertension or hypertension. Our findings demonstrated an association between improvements in wave reflection magnitude and leg muscle strength, suggesting that WBV training may decrease cardiovascular and physical disability risk in postmenopausal women.

What is known about this topic? WBV training decreases AIx in young normotensive women. An inverse correlation has been reported between AP and AIx with muscle mass in young men. Decreases in wave reﬂection have not been associated with improvements in muscle strength after conventional exercise training.

What this study adds? WBV training decreased pressure wave reﬂection and aortic BP in postmenopausal women with prehypertension and hypertension. Figure 2. Changes in aortic augmented pressure (a) and augmenta- The decrease in AP was correlated with the increase in leg muscle tion index (b) after 6 weeks of whole-body vibration training strength after WBV training. w (WBVT). Values are mean±s.e. *P ¼ 0.008 and P ¼ 0.001 different from before intervention (paired t-test). aP ¼ 0.027 and bP ¼ 0.006 group-by-time interaction. CONFLICT OF INTEREST The authors declare no conﬂict of interest.

ACKNOWLEDGEMENTS We thank Power Plate International for providing the vibration platforms. We also are grateful to the participants.

REFERENCES 1 Wykretowicz A, Adamska K, Guzik P, Krauze T, Wysocki H. Indices of vascular stiffness and wave reflection in relation to body mass index or body fat in healthy subjects. Clin Exp Pharmacol Physiol 2007; 34(10): 1005–1009. 2 Namasivayam M, Adji A, O’Rourke MF. Influence of aortic pressure wave components determined noninvasively on myocardial oxygen demand in men and women. Hypertension 2011; 57(2): 193–200. Figure 3. Relationship between the changes in leg muscle strength 3 Namasivayam M, McDonnell BJ, McEniery CM, O’Rourke MF. Does wave reflection and AP after 6 weeks of WBV training in postmenopausal women dominate age-related change in aortic blood pressure across the human life with prehypertension and hypertension. span? Hypertension 2009; 53(6): 979–985. 4 Russo C, Jin Z, Palmieri V, Homma S, Rundek T, Elkind MS et al. Arterial stiffness We found a negative relationship between changes in relative leg and wave reflection: sex differences and relationship with left ventricular diastolic muscle strength and AP. This relationship may have important function. Hypertension 2012; 62(2): 362–368. implications for older women with hypertension as increased 5 Delmonico MJ, Harris TB, Visser M, Park SW, Conroy MB, Velasquez-Mieyer P et al. muscle strength provides protection against all-cause mortality Longitudinal study of muscle strength, quality, and adipose tissue infiltration. Am J Clin Nutr 2009; 90(6): 1579–1585. in men with hypertension.7 The protection conferred by leg 33 6 Newman AB, Kupelian V, Visser M, Simonsick EM, Goodpaster BH, Kritchevsky SB muscle strength on the risk for coronary artery disease may be et al. Strength, but not muscle mass, is associated with mortality in the health, 30,32 related to reduction in AP. In middle-aged adults with high aging and body composition study cohort. J Gerontol A Biol Sci Med Sci 2006; cardiovascular risk, aortic AP, but not AIx, was independently 61(1): 72–77.

& 2014 Macmillan Publishers Limited Journal of Human Hypertension (2014) 118 – 122 Augmented pressure and muscle strength A Figueroa et al 122 7 Artero EG, Lee DC, Ruiz JR, Sui X, Ortega FB, Church TS et al. A prospective study of 22 Mahmud A, Feely J. Beta-blockers reduce aortic stiffness in hypertension muscular strength and all-cause mortality in men with hypertension. J Am Coll but nebivolol, not atenolol, reduces wave reflection. Am J Hypertens 2008; 21(6): Cardiol 2011; 57(18): 1831–1837. 663–667. 8 Heffernan KS, Chale A, Hau C, Cloutier GJ, Phillips EM, Warner P et al. Systemic 23 Hashimoto J, Westerhof BE, Westerhof N, Imai Y, O’Rourke MF. Different role of vascular function is associated with muscular power in older adults. J Aging Res wave reflection magnitude and timing on left ventricular mass reduction 2012; 2012: 386387. during antihypertensive treatment. J Hypertens 2008; 26(5): 1017–1024. 9 Cecelja M, Jiang B, Spector TD, Chowienczyk P. Progression of central pulse 24 Sherman S. Defining the menopausal transition. Am J Med 2005; 118(12B): 3–7. pressure over 1 decade of aging and its reversal by nitroglycerin a twin study. 25 Perk J, De Backer G, Gohlke H, Graham I, Reiner Z, Verschuren WM et al. European J Am Coll Cardiol 2012; 59(5): 475–483. Guidelines on cardiovascular disease prevention in clinical practice (version 2012): 10 Figueroa A, Going SB, Milliken LA, Blew RM, Sharp S, Teixeira PJ et al. Effects of The Fifth Joint Task Force of the European Society of Cardiology and Other exercise training and hormone replacement therapy on lean and fat mass in Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by postmenopausal women. J Gerontol A Biol Sci Med Sci 2003; 58(3): 266–270. representatives of nine societies and by invited experts). Atherosclerosis 2012 11 Kingsley JD, Figueroa A. Effects of resistance exercise training on resting and 223(1): 1–68. post-exercise forearm blood flow and wave reflection in overweight and obese 26 Chemla D, Nitenberg A, Teboul JL, Richard C, Monnet X, le Clesiau H et al. Sub- women. J Hum Hypertens 2012; 26(11): 684–690. endocardial viability ratio estimated by arterial tonometry: a critical evaluation in 12 Casey DP, Pierce GL, Howe KS, Mering MC, Braith RW. Effect of resistance training elderly hypertensive patients with increased aortic stiffness. Clin Exp Pharmacol on arterial wave reflection and brachial artery reactivity in normotensive Physiol 2008; 35(8): 909–915. postmenopausal women. Eur J Appl Physiol 2007; 100: 403–408. 27 Phillips MD, Flynn MG, McFarlin BK, Stewart LK, Timmerman KL. Resistance 13 Cortez-Cooper MY, DeVan AE, Anton MM, Farrar RP, Beckwith KA, Todd JS et al. training at eight-repetition maximum reduces the inflammatory milieu in elderly Effects of high intensity resistance training on arterial stiffness and wave women. Med Sci Sports Exerc 2010; 42(2): 314–325. reflection in women. Am J Hypertens 2005; 18(7): 930–934. 28 Sakurai M, Yamakado T, Kurachi H, Kato T, Kuroda K, Ishisu R et al. The relationship 14 Taaffe DR, Galvao DA, Sharman JE, Coombes JS. Reduced central blood pressure between aortic augmentation index and pulse wave velocity: an invasive study. in older adults following progressive resistance training. J Hum Hypertens 2007; J Hypertens 2007; 25(2): 391–397. 21(1): 96–98. 29 McEniery CM, Yasmin, Hall IR, Qasem A, Wilkinson IB, Cockcroft JR. Normal 15 Kingsley JD, McMillan V, Figueroa A. Resistance exercise training does not affect vascular aging: differential effects on wave reflection and aortic pulse wave postexercise hypotension and wave reflection in women with fibromyalgia. velocity: the Anglo-Cardiff Collaborative Trial (ACCT). J Am Coll Cardiol 2005; 46(9): Appl Physiol Nutr Metab 2011; 36(2): 254–263. 1753–1760. 16 Figueroa A, Gil R, Wong A, Hooshmand S, Park SY, Vicil F et al. Whole-body 30 Weber T, Auer J, O’Rourke MF, Kvas E, Lassnig E, Berent R et al. Arterial stiffness, vibration training reduces arterial stiffness, blood pressure and sympathovagal wave reflections, and the risk of coronary artery disease. Circulation 2004; 109(2): balance in young overweight/obese women. Hypertens Res 2012; 35(6): 667–672. 184–189. 17 Delecluse C, Roelants M, Verschueren S. Strength increase after whole-body 31 Vlachopoulos C, Aznaouridis K, O’Rourke MF, Safar ME, Baou K, Stefanadis C. vibration compared with resistance training. Med Sci Sports Exerc 2003; 35(6): Prediction of cardiovascular events and all-cause mortality with central 1033–1041. haemodynamics: a systematic review and meta-analysis. Eur Heart J 2010; 31(15): 18 Machado A, Garcia-Lopez D, Gonzalez-Gallego J, Garatachea N. Whole-body 1865–1871. vibration training increases muscle strength and mass in older women: a 32 Prince CT, Secrest AM, Mackey RH, Arena VC, Kingsley LA, Orchard TJ. Pulse wave randomized-controlled trial. Scand J Med Sci Sports 2010; 20(2): 200–207. analysis and prevalent cardiovascular disease in type 1 diabetes. Atherosclerosis 19 Verschueren SM, Roelants M, Delecluse C, Swinnen S, Vanderschueren D, 2010; 213(2): 469–474. Boonen S. Effect of 6-month whole body vibration training on hip density, 33 Silventoinen K, Magnusson PK, Tynelius P, Batty GD, Rasmussen F. Association of muscle strength, and postural control in postmenopausal women: a randomized body size and muscle strength with incidence of coronary heart disease and controlled pilot study. J Bone Miner Res 2004; 19(3): 352–359. cerebrovascular diseases: a population-based cohort study of one million Swedish 20 Figueroa A, Vicil F, Sanchez-Gonzalez M. Acute exercise with whole-body men. Int J Epidemiol 2009; 38(1): 110–118. vibration decreases wave reflection and leg arterial stiffness. Am J Cardiovasc Dis 34 Heffernan KS, Yoon ES, Sharman JE, Davies JE, Shih YT, Chen CH et al. 2011; 1(1): 60–67. Resistance exercise training reduces arterial reservoir pressure in older 21 Lythgo N, Eser P, de Groot P, Galea M. Whole-body vibration dosage alters leg adults with prehypertension and hypertension. Hypertens Res 2013; 36(5): blood flow. Clin Physiol Funct Imaging 2009; 29(1): 53–59. 422–427.

Journal of Human Hypertension (2014) 118 – 122 & 2014 Macmillan Publishers Limited