Body temperature in practitioners of a yoga breathing technique considered to be heat generating

Context: Suryabheda pranayama is traditionally described as increasing the inner fire and is believed to be heat generating. Aims: The present study aimed at determining whether the surface body temperature would increase after Suryabheda pranayama practice compared with sitting quietly for the same duration as a control. Materials and Methods: Nineteen participants with experience of Suryabheda pranayama practice (group mean experience +/- standard deviation, 30.2 +/- 22.8 months) were assessed in 3 sessions on separate days. The sessions were (i) Suryabheda pranayama with physiological locks or breath retention, (ii) Suryabheda pranayama without physiological locks or breath retention, and (iii) quiet sitting (control session). The axillary surface body temperature was monitored in all three sessions before (5 min), during (15 min), and after (5 min) the intervention. Ambient temperature and humidity in the recording cabin used for testing were noted. From the ambient temperature and humidity, the heat index was derived Statistical Analysis: Repeated measures analyses of variance were performed to compare values before, during, and after the 3 sessions, using SPSS version 24.0. Results: The surface body temperature increased during and after Suryabheda pranayama with physiological locks (P < 0.001;P < 0.001), Suryabheda pranayama without physiological locks (P < 0.01;P < 0.001), and quiet sitting (P < 0.001;P < 0.001) compared to the respective before values. Conclusion: The control (i.e., quiet sitting) and experimental sessions (i.e., suryabheda with locks and suryabheda without locks) showed a comparable increase in the surface body temperature. Hence, the increase in surface body temperature during and after experimental sessions does not appear to be related to the pranayama techniques. The possible factors which may have contributed to increased surface body temperature in the control and experimental sessions have been discussed.