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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
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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. |
