Official organ of the Association of Physiologist and Pharmacologists of India


Orginal Article
Volume 47 - No.1:January 2003 (index)

Indian J Physiol Pharmacol 2003; 47 (1): 27-33

Effect of Pranayam Training on Cardiac Function in Normal Young Volunteers




 Department of Physiology,

Jawaharlal Institute of Postgraduate Medical

Education & Research (JIPMER), Pondicherry - 605 006


(Received on June 16, 2002)


Abstract: Systolic tire intervals (STI) are non-invasive and sensitive tests for measuring the ventricular performance.  It has been reported that practice of pranayam modulates cardiac autonomic status and improves cardio-respiratory functions.  Keeping this in view, the present study was designed to determine whether pranayam training has any effect on ventricular performance as measured by STI and cardiac autonomic function tests (AFT).  Twenty-four school children were randomly divided into two groups of twelve each.  Group I (pranayam group) subjects were given training in nadishuddhi, mukh-bhastrika, pranav and savitri pranayams and practised the same for 20 minutes daily for a duration of 3 months.  Group II (control group) subjects were not given any pranayam training.  STI (QS2, LVET and PEP) and AFT (RRIV and QT/QS2) were measured in both the groups at the beginning and again at the end of three months study period.  Pranayam training produced an increase in RRIV and a decrease in QT/QS2 suggesting an enhanced parasympathetic and blunted sympathetic activity respectively.  QS2, PEP and PEP/LVET increased significantly, whereas LVET was reduced significantly in pranayam group.  In contrast, the changes in STI and AFT were much less marked in the control group.  Our study shows that three months of pranayam training modulates ventricular performance by increasing parasympathetic activity and decreasing sympathetic activity.  Further studies on a larger sample size may illustrate the underlying mechanism(s) involved in this alteration.


Keywords: pranayam, systolic, time intervals, RRIV, QT/QS2







With increased awareness and interest in health and natural remedies, yogic techniques including pranayams are gaining importance and becoming increasingly acceptable to the scientific community.  There is evidence that pranayam training produces deep psychosomatic relaxation (1, 2) and improvement of cardio-respiratory efficiency (3).  Chhina has reported that yogis are capable of controlling their autonomic functions (4) and Raghuraj et al have found that practice of nadishuddhi pranayam results in alteration of autonomic balance (5).  Telles et al have demonstrated that pranayam breathing through right nostril results in an increase in sympathetic activity whereas left nostril breathing reduces it (6).


Systolic time intervals (STIs) are useful, reproducible and non-invasive measures of left ventricular function (7, 8).  It is interesting to note that the term "noninvasive" was first used in connection with the STIs which are the earliest quantitative non-invasive tests used for the determination of cardiac function (7).  To the best of our knowledge there is no scientific report on the effect of pranayams on STI.  Hence, the present study was designed to study the effect of pranayams on cardiac performance as measured by STI.  Since, pranayams are known to influence the cardiac function by modulating autonomic activity (4, 5, 6), we also included in the present study, autonomic function tests (AFT) i.e. RR interval variation (RRIV) and QT/QS2) which are the indicators of parasympathetic and sympathetic activity respectively (9, 10).  The objectives of the present study were


(i)to study the effect of pranayam training on ventricular function as assessed by STI.

(ii)To explain these effects, (if any) in terms of alteration of cardiac autonomic status by studying the effects of pranayam  on RRIV and QT/QS2.                                                                                                                                                                                                                                
To study the effect of pranayam training on ventricular function as assessed by STI.                                                                         
To explain these effects, (if any) in terms of alteration of cardiac autonomic status by studying the effects of pranayam



Twenty-four healthy boys were recruited for the present study.  Their age was 13-15 (14.5 ± 0.25, SEM) years, weight 36-43 (39.28 ± 1.36, SEM) kg and height 154 – 161 (157 ± 0.2, SEM) cm.  After explaining the purpose and design of the study, informed consent was obtained from them as well as their parents.  None of the subjects had been engaged in yoga practice in the past nor were they doing any physical exercise prior to this study period.  The subjects were randomly assigned to two groups of twelve each.  Group I (pranayam group) subjects were taught nadishuddhi, mukh-bhastrika, pranav and savitri pranayams by a qualified yoga teacher and practised the same for twenty minutes daily, five days a week for a total duration of three months under our direct supervision.  Descriptions of the techniques of these pranayams are given elsewhere (11, 12).  Group II (control group) subjects were not taught pranayam and did not practice the same.  On the day of the test, subjects reported at our laboratory two hours after a light breakfast.  Recordings were taken at laboratory temperature of 27 ± l ºC. After ten minutes of supine rest, heart rate (HR), systolic pressure (SP), diastolic pressure (DP), STI and AFT were performed as described below. 

Heart rate & blood pressure: To avoid observer bias in the measurements, HR and blood pressure were recorded using automatic non-invasive blood pressure apparatus (Press-Mate BP 8800, Colin Corporation, Japan).  Rate-pressure-product (RPP), which is an index of myocardial oxygen consumption (13) was calculated as a product of HR and SP divided by 100 (RPP = HR x SP x 10-2). 

Systolic time intervals: STIs were calculated by simultaneous recording of electrocardiogram (ECG), phonocardiogram (PCG) and carotid arterial pulse.  Lead II ECG was recorded with conventional electrodes.  PCG was recorded with PCG transducer (TA-701T, Nihon Kohden Corporation, Japan) placed over 2nd intercostal space at right end of the sternum.  Carotid arterial pulse was recorded with a transducer (TK701 T, Nihon Kohden Corporation, Japan) positioned over a point of maximal pulsation of right carotid artery between the sternoclavicular joint and angle of jaw with the subjects face turned slightly towards the left shoulder (14).  The signals were fed into 8-channel polygraph (RM 6000, Nihon Kohden Corporation, Japan) and converted into digital format using analog-digital converter (Mi2,USA).  Ten seconds of recording strip having clear wave fronts were stored and analyzed later on with the help of data processing software (Biowindows, Modular Instruments Inc.  USA).  With this software STIs can be calculated with an accuracy of 1ms.  Electromechanical systole (QS2 ) was calculated from the beginning of the Q wave of ECG to the first high frequency component of second heart sound (Fig. 1). Left ventricular ejection time (LVET) was expressed as the interval between the upstroke of the carotid pulse and the dicrotic notch.  Pre-ejection period (PEP) was calculated from the difference between QS2 and LVET.  These three STIs and PEP/LVET ratio were computed for each cardiac cycle and average of ten continuous cardiac cycles was taken for statistical analysis (7).  Since STIs are known to vary with HR, their index values need to be calculated for proper interpretation of the results.  Index values for QS2,  LVET and PEP were calculated by applying Weissler's regression equation (15) as follows : 

QS2I = 2.1 (HR) + QS2; LVETI = 1.7 (HR) + LVET;

PEPI = 0.4 (HR) + PEP

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Fig. 1: Upper tracing: lead II Electrocardiogram, middle tracing: phonocardiogram and lower tracing: carotid arterial pulse. QS2 : electromechanical systole, LVET, left ventricular ejection time.

Autonomic function tests: For calculating RRIV, 150 successive R-R intervals were recorded under resting conditions and their mean and standard deviation (SD) were calculated.  The coefficient of variation of RR interval sequence was calculated by the formula: SD/mean x 100 (9).  For calculating QT/QS2 ratio, QT interval was calculated from the onset of Q wave to the termination of the T wave.  When end of the T wave was not very discrete, T wave termination was found by drawing a tangential line to the steepest descent of the T wave.  The point at which this tangent intersects the isoelectric baseline was considered as the termination of the T wave (10).  QT and QS2 were calculated for ten consecutive cardiac cycles and average QT/QS2 ratio was determined.

The data was subjected to statistical analysis using Student's paired "t" test.  A p value of less than 0.05 was accepted as indicating significant difference between the compared values.



The results are given in Table I. In group I, pranayam training produced a significant decrease in basal HR, the difference being statistically significant (P<0.01). On the other hand there was no significant change in the basal HR in group II.  SP and DP did not change much in either group.  RPP showed significant decrease in pranayam group (P<0.01) whereas in the control group the decrease in RPP was not statistically significant.  Pranayam training produced significant increase in QS2 and QS2I (P<0.05) and significant decrease in LVET and LVET1 (P<0.05). On the other hand there was no significant change in these parameters in the control group.  PEP, PEPI and PEP/LVET ratio increased significantly in the pranayam group (P<0.001). In the control group there was a less significant increase in these values (P<0.05). In group I RRIV increased by 19% following pranayam training whereas in group II it increased only by 2%, Pranayam training produced a significant decrease in QT/QS2 ratio (P<0.001) in group I subjects whereas in the control group it did not change after three months of the study period.

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Table I: Cardiovascular function in the two groups before and after three months study period



It has been reported that pranayam improves cardiorespiratory functions (1, 2, 3) and alters autonomic status (4, 5, 6).  Since there is no report on the effect of pranayam on STIs, we planned to study the effect of pranayam training on ventricular performance as measured by STIs.  In our group I subjects, pranayam  training of three months duration resulted in a significant reduction in basal HR.  In contrast, there was no change in basal HR of control subjects (Table 1).  pranayam  training did not produce any change in basal SP and DP. Our findings are consistent with those of' Udupa et al (16) who have reported a decrease in pulse rate but no change in blood pressure after pranayam training.  RPP is a known indicator of myocardial oxygen consumption and load on the heart (13). A significant decrease in RPP following pranayam training in group I subjects indicates a reduction in work done by the heart.  In an earlier study, we have demonstrated that pranayam  produces a significant decrease in oxygen consumption (1, 2).  Raju et al have also reported that pranayam training results in decrease in oxygen consumption (17).  These studies show that pranayam training produces an overall reduction in oxygen consumption, metabolic rate and load on the heart.

Pranayam breathing has been shown to alter the autonomic activity.  Telles et al have demonstrated that pranayam breathing through right nostril results in an increase in sympathetic activity whereas left nostril breathing reduces it (6).  Raghuraj et al have reported that slow pranayam (nadishuddhi) increases parasympathetic activity whereas fast pranayam (kapalabhati) increases the sympathetic activity (5).  Since Udupa et al (16) have reported that fast and slow pranayams have synergistic effects, we clubbed fast and slow pranayam in the present study.  Pranayam training in our subjects produced a significant decrease in QT/QS2 and this indicates a decrease in cardiac sympathetic activity (10).  RRIV showed statistically insignificantly but appreciable (19%) increase following pranayam training and this suggests an increase in cardiac parasympathetic activity (9).  On the other hand, there were no significant changes in these indicators of autonomic status in the control group (Table I). Hence, our study shows that pranayam training of three months duration produces a decrease in basal sympathetic tone and  increase in basal parasympathetic activity.

A decrease in sympathetic activity in our pranayam group is also confirmed by a significant increase in QS2 and QS2I and a significant decrease in LVET and LVETI.  In this connection it is interesting to note that Lewis et al have found a strong correlation between urinary catecholamine excretion and QS2I as a dose-dependent shortening of QS2I in response to intravenously administered positive ionotropic agents (18).  The significant prolongation of PEP and PEPI in our pranayam  group can be attributed to a diminished rate of left ventricular pressure rise (7).  McConahay et al (19) have reported increase in LVET and a decrease in PEP following physical exercise and attributed this to increase in sympathetic activity.  Since our finding in group I subjects following pranayam training are in the opposite direction of those of McConahay et al (19), we postulate that pranayam training produces decrease in sympathetic activity.  PEP/LVET ratio, which is the single most useful STI measure of left ventricular performance (7) increased in both the groups but the increase was more significant in pranayam group (Table 1).  It might be argued that this increase in PEP/LVET ratio indicates a compromise in myocardial function (8, 20).  However, the, initial value, of PEP/LVET ratio was low in our subjects and it increased towards the normal range during the three months of study period. Spitaels et al (21) have reported that the normal values of PEP/LVET ratio in children is 0.313 ± 0.05 which is very similar to the value of our group I subjects following pranayam  training. The increase in PEP, PEPI and PEP/LVET ratio in both the groups (Table 1) can be explained by the fact that PEP increases as the age advances from infancy to puberty (7, 21).  However, as the increase in these values was more pronounced in the pranayam group, we suggest that pranayam training promotes normalisation of' STI values.

In conclusion, the present study shows that three months of pranayam training, produces a significant decrease in RPP indicating a decrease in the load on the myocardium  This finding coupled with an overall reduction in oxygen consumption and metabolic rate as found in earlier studies (1, 2, 17) indicates the potential benefits pranayam in health and disease. This study also shows that pranayam training modulates ventricular performance by altering the cardiac autonomic tone.  The changes in ventricular performance are brought about by increased parasympathetic and decreased sympathetic activity. Further studies involving larger sample size and other indicators of cardiac performance may unravel the underlying mechanism(s) involved in this alteration.


We gratefully acknowledge the financial support from the Central Council for Research in Yoga and Naturopathy

(CCRYN), New Delhi.


1.       Madanmohan, Rai UC, Balavittal V, Thombre DP, Swami Gitananda. Cardiorespiratory changes during savitri pranayam and shavasan. The Yoga Review 1983; 3: 25-34.
2.       Rai  UC,  Madanmohan,  Subramanian  N,  Swami Gitananda. Oxygen consumption and ventilatory changes during savitri pranayam and shavasan. J Res Edit Indian Med 1982; 1: 23-26.
3.       Gopal K.S, Anantharaman V, Balachander S, Nishith SD. The cardiorespiratory adjustments in pranayama with and without bandhas in vajrasana. Indian J MedSci 1973; 27: 686-692.
4.       Chhina  GS. The voluntary  control  of autonomic responses in yogis. Proc International Union Physiol Sci 1974; 10: 103-104.
5.       Raghuraj  P,  Ramakrishnan  AG,  Nagendra  HR, Telles S. Effect of two selected yogic breathing techniques on heart rate variability. Indian J Physiol Pharmacol 1998; 42: 467-472.
6.       Telles S, Nagarathna R, Nagendra HR. Breathing through a particular nostril can alter metabolism and autonomic activities. Indian J Physiol Pharmacol 1994; 38:133-137.
7.       Lewis RP, Stanley ER, Forester WF, Boudoulas H. A critical review of the aystolic time intervals. Circulation 1977; 56:146-158.
8.       Ahmed  SS, Levinson  GE,  Schwartz  CJ,  Ettinger PO. Systolic time intervals as measures of the contractile state of the left ventricular myocardium in man. Circulation 1972; 46: 559-571.
9.       Ewing DJ. Analysis of heart rate variability and other non-invasive tests with special reference to diabetes mellitus. In Bannister R, Mathias CJ eds. Autonomic failure : A textbook of clinical disorders of the autonomic nervous system. Oxford, Oxford University Press 1992; 312-314.
10.    De Caprio L, Ferro G, Cuomo S, Voipe M, Artiaco D, De Luca N, Ricciardelli B. QT/QS, ratio as an index of autonomic tone changes. Am J Cardiol 1984; 53:818-822.
11.    Yoga : asanas, pranayama, mudras, kriyas. Chennai, Vivekananda kendra prakashan trust 2002: 71-72.
12.    Swami Gitananda. Yoga : Step-by-Step. Pondicherry, Satya press 1981: ppA-77, A-23, 56.
13.    Gobel FL, Nordstrom LA, Nelson RR, Jorgenson CR, Wang Y. The rate- pressure-product as an index of myocardial oxygen consumption during exercise in patients with angina pectoris. Circulation 1978; 57:549-556.
14.    Maher JT, Beller GA, Ransil BJ, Hartley LH. Systolic time intervals during submaximal and maximal exercise in man. Am Heart J 1974; 87: 334.
15.    Weissler AM, Harris WS, Schoenfeld CD. Systolic time intervals in heart failure in man. Circulation 1968; 37:149-159.
16.    Udupa KN, Singh RH, Settiwar RM. Studies on the effect of some yogic breathing exercises (pranayams) in normal persons. Indian J Med Res 1975; 63:1062-1065.
17.    Raju PS, Madhavi S, Prasad KVV, Reddy MV, Reddy ME, Sahay BK, Murthy KJR. Comparison of effects of yoga and physical exercise in athletes. Indian J Med Res 1994; 100: 81-87.
18.    Lewis RP, Boudoulas H, Forester WF, Weissler AM. Shortening of electromechanical systole as a manifestation of excessive adrenergic  stimulation in acute myocardialinfarction. Circulation 1972; 46:856-862.
19.    McConahay DR, Martin CM, Cheitlin ND. Resting and exercise systolic time intervals: Correation with ventricular performance in patients with coronary artery disease. Circulation 1972; 45: 592- 601.
20.    Gillian RE, Parnes WP, Khan MA, Bouchard RJ, Warbasae JR. The prognostic value of systolic time intervals in angina pectoris patients. Circulation 1979; 60:268-275.
21.    Spitaels S, Arbogast R, Fouron JC, Davignon A. The influence of heart rate and age on the systolic and diastolic time intervals in children. Circulation 1974:49:1107-1115.
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