Acute effect of Unilateral and Bilateral Nostril Breathing on Sympathovagal Balance in Yoga Practitioners and Healthy Male Volunteers

Objective: To study the effect of deep breathing and single nostril breathing on the heart rate, blood pressure and frequency domain parameters of heart rate variability in yoga practitioners (pranayama) and healthy male volunteers.

Background: Heart rate variability (HRV) is used as an index of cardiac autonomic function. HRV is influenced even by one single deep breath. Ancient Sanskrit literature describes that autonomic balance is maintained by rhythmic alterations of airflow through the 2 nostrils. Studies have shown that sympathetic activity increases after breathing through right nostril and parasympathetic activity increases after breathing through left nostril breathing.

Method: Study was conducted in Autonomic lab, Department of Physiology, JIPMER, Puducherry, India. Healthy volunteers in the age group of 18-20 were included in group 1and the volunteers practicing yoga for 2 months were included in group 2. Subjects were asked to perform the following procedure: breathing at comfortable rate with both nostril, left nostril and right nostril, deep breathing with both nostrils, left nostril and right nostril at the rate of 6 breaths per min. All the procedure was done in supine position and 5 min ECG was recorded immediately after each procedure with the breathing at a comfortable rate involuntarily with both nostrils and HRV was analyzed.

Result: Deep breathing in all the 3 methods increases HRV both in control and yoga group. Deep breathing through both the nostrils increased parasympathetic activity (HRV) in both the groups. Left nostril breathing increased parasympathetic activity and decreased sympathetic activity and the right nostril breathing increased sympathetic activity and decreased parasympathetic activity in both the groups. The finding was observed in both the groups but it was more pronounced in yoga group.

Conclusion: Regular practice of yoga (pranayama) enhances the lateralizing effect of autonomic function.