A small study sponsored by the American Council on Exercise is one of the first to look at whether hot yoga offers any more bang for your buck than traditional yoga. The study recruited 20 healthy men and women between 19 and 44, each of whom took a 60-minute yoga class in both a room heated to 21 C and one heated to 31 C. The classes were taken 24 hours apart and were led by the same instructor and featured the same poses.

Each subject wore a heart-rate monitor and swallowed an ingestible core body temperature sensor before taking part in the class. Core body temperature was recorded five minutes before the class, every five minutes during the class and five minutes after the class.

Heart rate was recorded every minute, with subjects also ranking their perceived rate of exertion on a scale from 6 to 20.

In the end, the researchers, who hailed from the Department of Exercise and Sport Science at the University of Wisconsin-La Crosse, noted very little difference in the core temperature and heart rate of the participants despite the difference in temperature between the two classes. Core temperature for the hot yoga participants was 37.6 C versus 37.4 C for the cooler studio.

As for the intensity of the workouts, both yoga practices would be classified as “light exercise,” with heart rate averaging about 56 per cent of maximum during the regular yoga class as compared to 57 per cent of maximum heart rate during the hot yoga class.