Yoga Breathing (Maheshwarananda's Modified Bhujangini Pranayama): A Randomized Study in Hypobaric Hypoxemia at 3,650 m Elevation.

Hypobaric hypoxemia represents a risk factor for body integrity and challenges its homeostasis. We examined whether practicing Maheshwarananda's modified bhujangini pranayama yoga breathing technique would influence hypobaric hypoxemia at an altitude of 3,650 m. An international randomized two-period, two-sequence crossover intervention study was conducted in September 2019 in the Himalayas. We compared 5-minute testing periods of pranayama breathing with normal resting breathing in 20 subjects divided randomly into two groups of 10 individuals; all had a daily practice of Maheshwarananda's modified bhujangini pranayama and were nonsmokers, lacto vegetarians, and alcohol abstainers. We measured the arterial saturation by pulse oximetry (SpO2; our primary outcome variable), end-tidal carbon dioxide partial pressure (EtCO2), respiratory rate, and heart rate at two altitudes: (1) 378 m (T0); and (2) 3,650 m (T1 = 2nd day, T2 = 4th day at the camp) immediately after finishing each testing period. We also monitored the presence of acute mountain sickness using the Lake Louise Scoring System. Mean SpO2 at 3,650 m increased right after the yoga breathing exercise from 88.60% to 90.35% at T1, and from 88.35% to 90.60% at T2 (T1 p = 0.007, T2 p = 0.004). No significant changes were observed in heart rate or EtCO2. The mean rate of normal control resting breathing was 13/min; the mean rate was 7/min during the yoga breathing. Right after Maheshwarananda's modified bhujangini pranayama hypobaric hypoxemia decreased as measured by SpO2, whereas EtCO2 and heart rate stayed comparable with the control resting breathing.