Immediate Effects of OM Chanting on Heart Rate Variability Measures Compared Between Experienced and Inexperienced Yoga Practitioners

Background: Chanting “OM” is a form of meditation that has numerous health benefits. However, the neurophysiological mechanisms underpinning its effect are surprisingly scarce. The present study aimed to investigate the effect of OM chanting on autonomic modulation, using heart rate variability (HRV), on experienced yoga practitioners and yoga naïve persons. Methods: This prospective study included 19 yoga practitioners (9 females and 10 males; group mean age ± standard deviation SD; 25.9 ± 3.2 years) and 17 yoga naïve persons (8 females and 9 males; group mean age ± SD; 24.8 ± 3.6 years) of both sexes and similar age range. Both the groups were assessed for HRV indices (time and frequency domain measures) before and after loud OM chanting for 5 min. Results: Baseline comparison using Mann–Whitney U test between groups showed yoga practitioners had significantly increased high frequency (HF) power ( P < 0.029) than nonyoga practitioners, signifying a state of tranquility before the chanting of OM. After 5 min of loud chanting of OM, a comparison between groups assessed using Wilcoxon Signed Ranks test revealed: HF Power, a component of the parasympathetic nervous system, was further amplified with a significantly increase ( P < 0.001) in the yoga practitioners group compared to nonyoga practitioners. Furthermore, this increase in HF power was positively correlated with the years of experience in yoga. Conclusion: The present study showed that a brief chanting of OM (5 min) might enhance parasympathetic nervous system activity, promote relaxation, and provide calmness. Further, this experience may be achieved effectively in individuals experienced in yoga than nonyoga practitioners.