Oxygen consumption during pranayamic type of very slow-rate breathing
Shirley Telles & T. Desiraju. Department of Neurophysiology, National Institute of Mental Health & Neuro Sciences, Bangalore. (Accepted July 30, 1991)
To determine whether the yogic Ujjayi pranayamic type of breathing that involves sensory awareness and consciously controlled, extremely slow-rate breathing including at least a period of end-inspiration breath holding in each respiratory cycle would alter oxygen consumption or not, ten males with long standing experience in pranayama, and volunteering to participate in the laboratory study were assessed. These subjects aged 28-59 years, had normal health appropriate to their age. Since Kumbhak (timed breath holding) is considered as an important phase of the respiratory cycle in the pranayama, they were categorised into two groups of five each, one group practising the short Kumbhak varieties of pranayama, and the other the long Kumbhak varieties of pranayama. The duration of Kumbhak phase was on an average 22.2 per cent of the respiratory cycle in the short Kumbhak group and 50.4 per cent in the long Kumbhak group. The oxygen consumption was measured in test sessions using the closed circuit method of breathing oxygen through the Benedict-Roth spirometer. Each subject was tested in several repeat sessions. Values of oxygen consumption of the period of pranayamic breathing, and of post- pranayamic breathing period, were compared to control value of oxygen consumption of the pre- pranayamic breathing period of each test session. The results revealed that the short Kumbhak pranayamic breathing caused a statistically significant increase (52%) in the oxygen consumption (and metabolic rate) compared to the pre-pranayamic base-line period of breathing. In contrast to the above, the long Kumbhak pranayamic breathing caused a statistically significant lowering (19%) of the oxygen consumption (and metabolic rate). The values returned to near normal in the post-pranayamic periods. The data provide a basis to indicate that different types of pranayamic breathing may lead to different types of alterations in the oxygen consumption and metabolic rate.
The nature of physiological alterations that possibly occur with different types of yogic practices is not well understood. The present study was aimed to determine whether oxygen consumption and metabolism would be altered or not in practitioners of Yoga during the consciously regulated, extremely slow-rate, Ujjayi pranayamic type of timed breathing that includes breath- holding phase (Kumbhak) in each cycle of respiration. It was aimed to assess this in two variants of the pranayama that differed in the ratio of duration of the Kumbhak phase in the breathing cycle, one being short and the other long.
It was reported in two earlier studiesl,2 involving only one subject in each, that oxygen consumption during Ujjayi pranayama, when compared to the preceding period, increased in one of the subjects by +19 per cent and in the other subject by +9 per cent. It is necessary however, to examine more subjects practising pranayama to check whether such an impression of increase which is based on the data of only two subjects will be generally valid. Therefore, the present study was undertaken on ten subjects to assess the effects of two pranayamic variants on oxygen consumption of subjects under each variant. Further, it was aimed to obtain data of each subject as averages of several repeat test sessions (over 7) to improve reliability.