Energy Expenditure and Ventilatory Responses Dur!Ng Virasana -A Yogic Standing Posture

Home , Asana, Kurmasana, Shavasana, Virasana

Indian J Physiol Pharmacol 1993; 37(1) :45-50

ENERGY EXPENDITURE AND VENTILATORY RESPONSES DUR!NG VIRASANA -A YOGIC STANDING POSTURE

L. RAI* AND K. RAM

Department of Physiology, Central Research Institute for Yoga, 68, Ashok Road, New Delhi-110 001

( Received on May 26, 1992 )

Abstract: Energy expenditure and ventilatory responses to yogic standing posture of Viras ana were studied on 10 healthy men (25-37 years of age). The results of various responses respectively to the horiwntal supine, Chair-silting and Virasana were: Minute Ventilation (VE) 7.64,8.61 and 18.67 Urnin; Respiratory Frequency (FR) 15.71, 15.70 and 21.45 Breath! min; Tidal Volume (VT) 0.496, 0.544 and 0.827 L/rnin; Oxygen consumption (VOz) 0.127, 0.234 and 0.573 Llmin; Carbondioxide Elimination (VCOz) 0.127, 0.134 and 0.420 Llrnin; Respiratory Exchange Ratio (RER) 0.58. 0.57 and 0.69; Heart Frequency (FH) 65.2, 74.5 and 104.4 beats/min; Oxygen Pulse (OzP) 3.32, 3.17 and 5.45 mllbeat; Ventilatory Equivalent (VE-EQ) 36.78, 37.12 and 33.85; MUltiple of Resting VOz (METS) 0.96, 1.05 and 2.53 and Metabolic Cost (MC) 1.04, 1.13 and 2.76 Cal/min. Virasana posture was characterised by higher VE, FR. VT, VOz' VCOz' FH and OzP with lesser VE-EQ. The observations suggest that Virasana induces temporarily a hypermetabolic state characterised by enhanced sympathetic nervous system activity which gets inhibited during the adoption of resting supine shavasana posture.

Key words: Vi ras ana metabolic cost oxygen pulse ventilatory functions

INTRODUCTION N1ETHODS

The energy spent by the body in a particular The subjects of this study were ten, healthy male activity can be measured by the amount of oxygen yoga-proficient teachers between 25-37 years of age consumed by the body per minute or indirectly by with a mean weight of 58.7 ± 5.2 kg and mean height measuring the rate of respiration, heart rate, minute of 169.3 ± 6.0 cm. The body surface area ranged from ventilation, blood pressure and temperature of the body 1.60 to 1.84 m2. They were all non-smokers and had etc. The higher rate in these parameters being indicative some practice of Virasana. of increased expenditure and vice-versa. Numerous The experiments were carried out in the morning studies on varied types of physiological, biochemical in empty stomach after about 20 min rest by assuming and endocrinal responses to different yogic postural Shavasana technique in the laboratory. Various exercises (1,2,3,4,5) and some even including the ventilatory functions were recorded by connecting the immediate effects of various yogic postures in terms of subject to 'Mijnhardt Oxycon-4' (Holland) through a oxygen consumption, carbondioxide elimination, the face mask. A photo-electric transducer was attached to minute ventilation etc. (6,7,8,9,10) have been reponed one of the ear lobes for monitoring the heart frequency in literature. The results of these studies have revealed (FH) and oxygen pulse (02P), The cardio-ventilatory that each yogic asana besides manifesting broadly parameters of minute ventilation (VE), respiratory similar trends appears to have some degree of specificity frequency (FR), tidal volume (VT), Oxygen in terms of magnitude of influence. It is in this context consumption (V0 ), Oxygen consumption per kg body that the present study to determine the effect of an 2 weight per min (VO/kg), Carbondioxide elimination important yogic semi-standing posture of Virasana on energy spent by the body and other related cardio (VCO), respiratory exchange ratio (RER), ventilatory ventilatory responses was designed. equivalent (VE-EQ) and multiple of resting V02

·Corresponding Author 46 Rai and Ram Indian J Physiol Pharmacol 1993; 37(1)

(METS) were recorded and simultaneous computer Except during the performance of Virasana all the analysis in oxycon-4 and data obtained was carried out readings were teken after a period of atleast 20 min in a print out at an interval of every half min, whence had elapsed after assuming a particular posture. The the averages for different test parameters were period was considered to be sufficient for circulatory computed. and metabolic adjustments and to develop a steady state in the subject. During Virasana, however, the recording The sequence of postures followed during the of observations was made from 0 min to till the subject recording of observation was: (i) silting relaxed-in could afford to sit in the posture cornfortably. chair, Fig. I (a), (ii) lying horizontally supine (yogic shavasana), Fig. 1 (b), and (iii) Virasana, Fig. I (c). The study was based on a self-control system The first two postures of silLing relaxed-in-chair and where the initial preposture observations obtained during horizontal supine shavasana served as controls and the relaxed state of horizontally supine position reference levels for the yogic semi-standing posture of (shavasana) were compared with the observations Virasana. obtained during chair-sitting and Virasana. Brief account of the techniques followed for adopting Shavasana posture and Virasana posture were as follows :- Technique ofperforming Shavasana : During the performance of this posture the subject lay in the supine position making lower limbs 30 degree apart and the upper ones making an angle of 15 degrees with the trunk. During this asana the forearms were in the mid (a) prone position with fingers semiflexed. The eyes were kept closed with eyelids drooping (Fig. I (b)). During the shavasana posture, the subjects performed slow, rhythmic, diaphragmatic breathing with a short pause after each inspiration and longer one at the end of each expiration. During this posture the individuals were instructed to re1:lx their muscles completely.

Technique ofperforming Virasana : Stand on the ground with the left leg stretched backwards and the right knee bent. The U<;ts of the hands were clenched, with the thumbs tuckc;i' inside them. The right arm was stretched forward in front of the chest and the left arm bent back. The trunk was stretched back-wards with full strength and the leg was kept straight. Both eyes were kept open without blinking (Fig. I c). The asana was performed again by reversing the position of the lower limbs, i.e. by keeping the lefr foot forward and the right foot backward. RESULTS

Out of a total of 10 subjects, 6 subjects manifested the initial basal breathing frequency (observed during relaxed shavasana posture) higher than 10 i.e. in the mean range of II to 21 per min. While the other 4 Fig. 1: (a) Sitting Relaxed-in-Chair(CS); (b) Horizontal Supine subjects exhibited the initial basal breathing frequency Yogic Shavasana (HS); and (c) Virasana - a Yogic less than 5 i.e. in the range of 3.5 to 4.7 per min. Based standing Asana (A). Indian J Physiol Pharmacal 1993; 37(1) Responses during Virasana 47

on the criteria of basal breathing frequency either being greater production of carbondioxide and higher more than 10 or less than 5, the subjects were respiratory exchange ratio. A similar trend of changes categorised into two groups comprised respectively of in these ventilatory responses, though less in magnitude 6 and 4 subjects. was observed in a comfortable posture ofsitting relaxed in-chair when compared with the reference to control The mean results of observations of these two values observed during the horizontal supine shavasana groups of individuals were analysed sepamtely and their posture. details are described below :- B. Cardio-ventilatory responses to Virasana in A. Cardio-ventilatory responses to Virasana in individuals manifesting initial lower breathing individuals manifesting initial higher breathing frequency : Tables I to IV also give the comparative frequency: Tables I to IV give the comparison of the data on cardio-ventilatory responses in a group of four data on cardio-ventilatory responses conducted in a young healthy adult men having initial breathing group of 6 healthy adult men, proficient in yoga having frequency less than five in (i) horizcntal supine initial breathing frequency more than 10 in (i) horizontal shavasana posture, (ii) sitting relaxed-in-chair and (iii) supine shavasana, (ii) sitting relaxed-in-chair and (iii) in the yogic seated posture of Virasana. It is seen from in a yogic semi-standing posture of Virasana. It appears these tables that in these subjects with low respiration from these tables that the yogic posture of Virasana rate, Virasana was characterised by the tendency to was characterised in these volunteers by greater minute increase breathing frequency at the cost of a decrease ventilation, greater tidal volume, higher oxygen uptake, in tidal volume, besides showing increase in minute

TABLE I: Mean values ± SO of minute ventilation (VE), breathing frequency (FR) and tidal volume (TV) during the perfonnance of Virasana in relation to resting posture ofChair-sitting and Shavasar'.a.

Parameters of FR> 10 (n = 6) FR<5(n=4) Assessment POSTURES POSTURES HS CS A HS CS A

1. VE(L/min) M 7.64 8.61 18.67 4.30 4.92 12.75 SO 1.38 1.50 6.66 LI5 2.66 6.64 (HS)VS(CS) (CS)VS(A) (HS)VS(A) (HS)VS(CS) (CS)VS(A) (HS)VS(A) P NS < O.ol <0.005 NS NS <0.05 2. FR (Breaths/min) M 15.71 15.70 21.45 4.28 5.75 15.48 SO 3.21 2.39 6.11 0.53 2.07 8.84 (HS)VS(CS) (CS)VS(A) (HS)VS(A) (HS)VS(CS) (CS)VS(A) (HS)VS(A) P NS <0.05 <0.05 NS NS <0.05 3. VT (Litres) M 0.49 0.54 0.83 1.03 0.86 0.96 SO 0.09 0.07 0.25 0.27 0.32 0.26 (HS)VS(CS) (CS)VS(A) (HS)VS(A) (HS)VS(CS) (CS)VS(A) (HS)VS(A) P NS <0.025 <0.01 NS NS NS Each mean value shown in the columns of Horiwntal Supine-shavasna (HS) and Chair-sitting posture (CS) is a pooled mean of a set ofobservations taken at halfmin interval for a period of 5 min (after elapsing 10 min of assuming the particular posture) on identical experimental sessions held on 6 consecutive days of a week. The mean value shown in the column ofAsana (A) is a pooled mean ofset ofobservations taken at halfmin interval for the same individuals during the perfonnance of the asana within individual's enduring capacity on a given experimental day. 48 Rai and Ram Indian J Physiol Pharmacal 1993; 37(1)

TABLE II: Mean values SO of oxygen consumption (Y0 ), carbondioxide production (VC0 ) and respiratory exchange ratio ± 2 2 (RER) during the perfomlance of Yirasana in relation to resting postures ofchair-sitting and Shavasana.

Parameters of FR> 10 (n =6) FR < 5 (n =4) Assessment POSTURES POSTURES

HS CS A HS CS "

4. Y02 (Umin) M 0.22 0.23 0.57 0.19 0.19 0.50 SO 0.05 0.05 0.23 0.04 0.102 0.24 . (HS)YS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)YS(A) (HS)YS(A)

P NS <0.005 <0.0005 NS <0.05 <0.05

5. YC02 (Umin) M 0.13 0.13 0.42 0.12 0.12 0.32 SO 0.03 0.03 0.21 0.04 0.06 0.16 (HS)YS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)YS(A) (HS)YS(A) P NS <0.01 < om NS <0.05 <0.05 6. RER M 0.58 0.57 0.68 0.65 0.63 0.63 SO 0.99 0.09 0.14 0.01 0.02 0.06 (HS)YS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)YS(A) (HS)YS(A) P NS NS NS NS NS NS

Each mean value shown in the columns ofHorizontal Supine-shavasana (HS) and Chair-sitting posture (CS) is a pooled mean of a set ofobservations taken at halfmin interval for a period of 5 min (after elapsing 10 min of assuming the particular posture) on identical experimental sessions held on 6 consecutive days of a week. The mean value shown in the column ofAsana (A) is a pooled m.::an ofset ofobservations taken at halfmin interval for the same individuals during the performance of the a~ana within individual's enduring capacity on a given experimental day. ventilation, higher oxygen consumption, higher pulmonary parameters that were simultaneously carbondioxide elimination, higher oxygen pulse and recorded during the performance of Virasana. The result higher metabolic cost as compared to the reference of increased oxygen consumption and carbondioxide controlled values observed during horizontal supine elimination during Virasana indicate that Virasana shavasana posture. though a static posture appears to be a moderate exercise in comparison to Chair-sitting or horizontal supine DISCUSSION posture. From the results of ventilatory responses studied As regards the frequency of breathing and minute during three positions or chair-sitting, horiwntal supine ventilation, it may be said that the yoga proficient shavasana and yogic semi-standing posture of Virasana, subjects in the study manifesting higher initial breathing it is obvious that the physiologic parameter which is frequency increased their ventilation by allowing increased significantly during the performance of increases in respiratory frequency and tidal volume Virasana is minute ventilation. The minute ventilation during the three postures, while those subjects who was largest during Virasana, smallest in horizontal manifested initial breathing frequency less than five supine shavasana posture and intermediate in chair increased their ventilation by allowing increases in silting position. In addition semi-standing to this, there respiratory frequency as tidal volume in these cases occurred significant changes in a series of other rather decreased. Indian J Physiol Pharmarol 1993; 37(1) Responses during Virasana 49

TABLE III : Mean values ± SO of heart frequency (FH) oxygen pulse (Ol) and ventilatory equivalent (VE-EQ) during the perfonnance of Virasana in relation to resting postures of chair-silting and Shavasana. FR> 10 (n = 6) FR<5(n=4) Parameters of Assessment POSTURES POSTURES HS CS A HS CS A

7. FH (Beats/min) M 65.19 74.49 104.35 71.13 76.11 101.40 SO 6.26 6.78 11.08 6.88 6.69 7.33 (HS)YS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)YS(A) (HS)YS(A) P < 0.025 < 0.005 < 0.0005 NS < 0.001 < 0.001 8. 02P (mia/beats) M 3.33 3.17 5.45 2.69 2.46 4.88 SO 0.69 0.56 2.06 0.57 1.14 2.21 (HS)YS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)VS(A) (HS)YS(A) P NS < 0.025 <0.05 NS NS NS 9. VE·EQ M 36.78 37.12 33.85 22.75 26.85 25.72 SO 6.04 4.08 4.13 0.84 3.19 1.98 (HS)VS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)YS(A) (HS)YS(A) P NS NS NS <0.05 NS <0.05

It may be inferred from these findings that the observations suggest that Virasana is a moderate type semi-standing Virasana posture was characterised by of postural exercise and appears to have its application , • value in conditions of low cardia-respiratory reserves higher VE, V02 veo2 FH, 0l, lesser VE-EQ and higher metabol ic cost in relation to horizontal supine especially in patients in whom heavy exercises are shavasana posture and posture of sitting relaxed-in contra-indicated. However, it is to be noted that no chair. The difference between these parameters in the claim is made here of any additional efficiency for two positions of horizontal supine and chair-silting, Virasana than as a postured exercise. however, was not significant statistically. These 50 Rai and Ram Indian J Physiol Phannacol 1993; 37(1)

TABLE IV : Mean values ± SO of METS (Y02measuredN02 resting), oxygen consumption per kg body weight (VCOjkg) energy expenditure in CaVmin during theperformaneeofVirasanain relation to resting postures ofchair-sitting and Shavasana.

Parameters of FR> 10 (n = 6) FR < 5 (n = 4) Assessment POSTURES POSTURES

HS CS A HS CS A

10. METS M 0.97 1.05 2.53 0.81 0.75 2.10 SO 0.23 0.23 1.00 0.15 0.37 0.90

(HS)VS(CS) (CS)VS(A) (HS)VS(A) (HS)VS(CS) (CS)VS(A) (HS)VS(A) P NS <0.01 <0.005 NS <0.002 <0.002

11. VOjkg M 3.67 4.07 9.85 3.15 2.98 8.32 SO 0.74 0.85 3.81 0.67 1.36 3.42 (HS)VS(CS) (CS)VS(A) (HS)VS(A) (HS)VS(CS) (CS)VS(A) (HS)VS(A) P NS <0.01 < 0.005 NS <0.002 <0.002 12. CaVmin M 1.04 1.13 2.76 0.91 0.90 2.12 SO 0.23 0.24 1.11 0.23 0.49 1.15 (HS)VS(CS) (CS)YS(A) (HS)YS(A) (HS)YS(CS) (CS)YS(A) (HS)YS(A)

P NS < 0.01 < 0.01 NS <0.05 <0.05

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