Body Temperature and Energy Expenditure During and After Yoga Breathing Practices Traditionally Described as Cooling

BACKGROUND: In traditional yoga texts, sheetali and sitkari pranayamas are described as cooling. The present study was aimed at recording the surface body temperature, oxygen consumed, and carbon dioxide eliminated before, during, and after performance of sheetali and sitkari pranayamas.
MATERIAL AND METHODS: Seventeen healthy male volunteers with ages between 19 to 25 years (average age 20.7±1.8 years) were assessed in 4 sessions, viz. sheetali pranayama, sitkari pranayama, breath awareness and quiet lying, on 4 separate days, in random sequence. The axillary surface body temperature (TRUSCOPE II, Schiller, China) and metabolic variables (Quark CPET, COSMED, Italy) were recorded in 3 periods: before (5 minutes), during (18 minutes), and after (5 minutes), in each of the 4 sessions. The heat index was calculated in the before and after periods, based on recordings of ambient temperature and humidity. Data were analyzed using SPSS (Version 24.0).
RESULTS: Body temperature increased significantly during sheetali and sitkari (p<0.05, p<0.01; respectively) while it decreased after breath awareness and quiet lying down (p<0.01, p<0.001; respectively) when compared with respective post-exercise states. Oxygen consumption increased by 9.0% during sheetali (p<0.05) and by 7.6% during sitkari (p<0.01) while it decreased significantly during (p<0.05) and after (p<0.01) quiet lying down compared to respective pre-exercise states.
CONCLUSIONS: The results do not support the description of these yoga breathing practices as cooling. These yoga breathing practices may be used to induce a mild hypermetabolic state.

Keywords: Body Temperature Changes, Carbon Dioxide, Oxygen Consumption, Yoga