EFFECT OF SIX WEEKS OF SHAVASAN TRAINING ON SPECTRAL MEASURES OF SHORT-TERM HEART RATE VARIABILITY IN YOUNG HEALTHY VOLUNTEERS

Madanmohan*, A. B. Bhavanani, E. S. Prakash,M. G. Kamath and J. Amudhan

Department of Physiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) Pondicherry - 605 006

In an earlier work from our laboratory, we have demonstrated the effectiveness of shavasan, a yogic relaxation technique, in producing psychosomatic relaxation (1). The blood pressure (BP) lowering effect of shavasan has been demonstrated previously in subjects with hypertension (2). The cardiovascular effects of shavasan may at least in part be due to its effects on autonomic regulation of heart rate and blood pressure. Heart rate variability (HRV) analysis has come to be increasingly used in physiologic research studies as a noninvasive tool to examine the autonomic regulation of cardiovascular function. It describes the variability in instantaneous heart rates and assesses modulation of cardiac cycle time by intrinsic biological rhythms (3, 4, 5). Oscillations in instantaneous heart rates occur at high frequencies (0.15-0.40 Hz), low frequencies (0.04-0.15 Hz) and at very low frequencies (0.003-0.04 Hz) due to different physiologic mechanisms and these have been inferred from pharmacologic studies (3, 4, 5, 6). For a detailed discussion of the physiologic foundations of HRV, consult Akselrod (3, 4), Eckberg (5) and Pagani et al (6). Time domain analysis is a simple method to quantify overall HRV whereas power spectral analysis provides a means of studying different mechanisms responsible for variability in instantaneous heart rates. Raghuraj et al have studied the effect of two yogic breathing techniques on heart rate variability (7). The effect of shavasan training on HRV has not been studied so far. Hence, we planned to determine whether shavasan training of short duration has any effect on the low frequency and high frequency components of heart rate variability.