A Comparative Study of Cardiovascular Autonomic Function Tests in Yoga Practitioners and Controls

Abstract

Background: In the present age, a great emphasis is being laid on the practice of yogic postures as a form of highly effective physical exercise for keeping the body healthy and also for the control of disease process. Rhythmic breathing controls the mind, lungs and heart which are located in the thoracic cage and are under the control of autonomic nervous system. The aim of this study was to evaluate the cardiovascular autonomic function tests among yoga practitioners. Method: 75 healthy volunteers (aged 18-31 years)were divided in to three groups; the first two yoga groups ( each group ,n=25 ) consisted of subjects who were practicing the yoga (pranayama and suryanamaskarams) for less than 2 years and more than 2 years, respectively and the third group was controls (n=25). Autonomic function tests were performed for both sympathetic and parasympathetic activity ,which include deep breathing test, valsalva maneuver, heart rate response to standing posture (30:15 ratio) , orthostatic hypotension test and sustained hand grip test. Results: The statistics showed a significant value for heart rate variability , 30:15 ratio ,hand grip test, othrostatic hypotension test and valsalva ratio in group 1 and 2 yoga practitioners (p<0.05) than in controls. But no significant difference observed in terms of resting heart rate in all groups. The overall ewing's autonomic dysfunction score was high in controls compared to yoga practicing subjects ((p<0.05). Conclusion: It is evident that yoga develops an ability to control cardiovascular autonomic functions and would prepare the body to overcome stress by modulating and optimizing sympathetic activities.