Heart rate variability changes during and after the practice of bhramari pranayama

Background: Yoga is an ancient Indian science as well as the way of life. Pranayama is one of the most important yogic practices. Bhramari pranayama was shown to produce a reduction in blood pressure after the practice and thus reported to produce parasympathetic activity. However, there are no known studies reported the heart rate variability (HRV) changes either during or after the practice of Bhramari. Hence, this study aims at evaluating the HRV changes during and after the practice. Materials and Methods: Sixteen (9 males, 7 females) healthy volunteers with the mean ± standard deviation age of 23.50 ± 3.01 years were recruited. All the subjects performed Bhramari pranayama for the duration of 5 min. Assessments were taken before, during, and immediately after the practice of pranayama. Statistical analysis was performed using students paired samples t-test, Wilcoxon signed-ranks test and repeated measures of analysis of variance and Post-hoc analysis with Bonferroni adjustment for multiple comparisons. Results: Results of this study showed a significant increase in HR and low frequency spectrum of HRV and a significant reduction in high frequency spectrum of HRV during the practice of Bhramari which revert to normal after the practice. Conclusion: Results of this study suggests that there might be a parasympathetic withdrawal during the practice of Bhramari. However, further studies are required to warrant the findings of this study.