Cardiac autonomic modulation during yoga postures and cycling: An “Acute State Effect”

Objectives: Health benefits of aerobic exercises and Yogaasana (Yoga Postures) in lifestyle diseases are well known. There are pointers that these health benefits may be mediated through cardiac autonomic modulation. “Acute State effects” of autonomic modulation during aerobic exercise is fairly established; however there is relative dearth of information about it during Yogasana (Yoga Postures). The purpose of present study is to explore “Acute State Effect” of cardiac autonomic modulations during Yogasana (postures) and mild aerobic exercise (cycling) using heart rate variability (HRV) a cardiac autonomic marker in Yoga naïve volunteers. Materials and Methods: Thirty consenting volunteers between eighteen to twenty five years, of both genders performed test protocol comprised of four blocks of modified yoga postures, one block of cycling each of five minute duration and a block of supine rest that served as baseline. High sampled ECG (1 KHz) was recorded during protocol for HRV analysis. Friedman test for multiple blocks comparison and Wilcoxon signed rank test for pair wise comparison was employed. P < 0.05 considered as significant. Results: Multiple block comparison of HRV indices (P < 0.0001) and for breathing rate (P < 0.0004) were highly significant. Compared to resting baseline a pattern of vagal withdrawal (decrease in HF nu) with increment in average heart rate was observed during modified yogasanas and cycling. Shavasana showed pattern of parasympathetic reactivation with decrement in average heart rate. Conclusion: The pattern of autonomic modulation in Yoga naïve performing modified yogasanas was similar to mild intensity cycling. Shavasana showed pattern of post exercise recovery.