A recent study showed no difference in oxygen consumption (caloric expenditure) between hatha yoga sessions performed at room temperature and at 95 degrees. Although no differences in metabolic cost were shown, heart rate was significantly higher during hot yoga compared to the room temperature condition. This lends more insight into the differences in physiological responses to yoga with or without the heated environment and further cautions against the use of heart rate monitors to estimate calories burned during hot yoga. Relying exclusively on heart rate to gage exercise intensity may result in an overestimation of caloric expenditure due to the exaggerated heart rate responses during hot yoga. The sessions in this study were only 20 minutes, which are atypical of a hatha yoga class. This should be kept in mind when interpreting these findings. It is unknown whether a longer practice would have yielded similar results.