A recent study conducted at AIIMS Bhopal examined the effects of two pranayama techniques, right nostril breathing (RNB) and left nostril breathing (LNB), on heart rate variability (HRV) in healthy kriya yogi volunteers who have been regular practitioners for the last 10-20 years. The study, titled "Immediate autonomic changes during right nostril breathing and left nostril breathing in regular yoga practitioners," was published in a PubMed indexed Journal of Education and Health Promotion.
Pranayama is an ancient Indian practice that uses voluntary regulation of breathing to make respiration rhythmic and calm the mind. Nadisuddhi pranayama involves inhaling and exhaling through alternative nostrils for successive respiratory cycles to purify subtle energy paths. Surya bhedi pranayama, which involves completing the respiratory cycle through the right nostril exclusively, is known to generate heat. On the other hand, Chandra bhedi pranayama, which involves completing the respiratory cycle through the left nostril exclusively, is known to dissipate heat and cool the body.
The study recorded the electrocardiogram (ECG) for HRV analysis using the Dinamika HRV-Advanced Heart Rate Variability Test System, Moscow, Russia. The resting and during readings of HRV parameters were compared, and post hoc analysis was done using Bonferroni and Holm multiple comparisons for repeated measures.
The results showed that the time domain parameters SDNN and RMSSD were increased at a high level of statistical significance during both pranayama maneuvers. The frequency domain parameters LF and LF/HF ratio also increased significantly. The LF values represent parasympathetic activity and can be very high when the subject is in a state of relaxation with slow and even breathing in both RNB and LNB, indicating an increase in parasympathetic activity rather than an increase in sympathetic regulation.
However, the study found that there was not much difference in the immediate effects of the two pranayamas on HRV in regular yoga practitioners.
