The physiological responses to Bikram yoga in novice and experienced practitioners

Bikram yoga has gained a large following, possibly because of widespread claims boasting energy expenditure of up to 1000 calories per session. However, these claims are unfounded because no scientific study has investigated the metabolic response to a complete, standardized Bikram yoga class.

This study intends to determine energy expenditure, heart rate, and sweat rate in novice and experienced practitioners from a standardized Bikram yoga class.

Data were collected in the environmental chamber of the Exercise Physiology Laboratory at San Diego State University in California, USA.

Male (n = 5) and female (n = 19) participants between the ages of 18 and 57 y were recruited through flyers in yoga studios throughout San Diego. Participants were classified as experienced or novice practitioners, having completed ≥20 or <20 sessions, respectively.

Participants were guided through a standardized 90-min yoga class performed in a hot environment using Bikram's Standard Beginning Dialogue, while expired gas was collected and heart rate was recorded.

Energy expenditure, calculated via oxygen uptake, and heart rate were determined for each posture and transition period. In addition, sweat rate and core temperature were recorded for each participant.

Mean (±SD) relative VO2 for the entire 90-min session was 9.5 ± 1.9 mL × kg-1 × min-1, ranging from 6.0 to 12.9 mL × kg-1 × min-1. Mean absolute energy expenditure was 286 ± 72 kcals, ranging from 179 to 478 kcals. Independent sample t tests revealed significant differences (P < .05) in relative energy expenditure, heart rate, ending core temperature, and sweat rate between experience levels. Mean relative energy expenditure was 3.7 ± 0.5 kcal/kg in novice practitioners and 4.7 ± 0.8 kcal/kg in experienced practitioners. Percentage of predicted maximum heart rate and sweat rate were 72.3% ± 10.6% and 0.6 ± 0.2 kg/h in novice practitioners and 86.4% ± 5.2% and 1.1 ± 0.5 kg/h in experienced participants. All postures were classified as light-to-moderate intensity according to the American College of Sports Medicine (ACSM) standards.

Bikram yoga meets requirements for exercise of light-to-moderate intensity and, theoretically, could be used for weight maintenance or weight loss if practiced several times per week.