Hot yoga is safe - if it's not too hot
HOT yoga - and hot-barre and hot-spinning classes - is a booming trend, with yogis crowding into sweltering rooms to twist their bodies to the point of exhaustion.
But whether or not yoga in heated rooms, sometimes up to 40.5 deg C, is safe has been a point of contention.
A small study recently suggested that it is perfectly safe for healthy adults, as long as it is not too hot.
According to the study from the American Council on Exercise, as long as you stay hydrated, hot yoga is just as safe as yoga in more moderate temperatures, Prevention magazine reports.
University of Wisconsin-La Crosse researchers recruited 20 healthy adults between the ages of 19 and 44.
The core body temperature of the subjects was measured both after a 60-minute Vinyasa yoga class in a room set to 21 deg C, and after a 60-minute hot-yoga class in a room heated to around 32 deg C to 35 deg C, with 35 per cent to 40 per cent humidity.
After both classes, the students' core temperature rose to an average of 37.2 deg C, which is well below the unsafe threshold of 40 deg C, said study author John Porcari.
"When you're exercising, it's almost like your body shuts down if you get to that level (40 deg C)," he said in the report. "It's considered dangerous, and heat-related illness is almost impending."
If you are not hydrated, this could cause problems. Dr Porcari suggested drinking plenty of water - 177ml to 236ml immediately before class and more during class as needed.
Also, if you are new to hot yoga, keep in mind that it can take anywhere from 10 days to two weeks for most people to fully acclimatise to exercising in the heat, so be sure to give yourself time to adjust, he said.
Still, more tests need to be done to gauge the safety of Bikram yoga, which involves 90 minutes in a room heated to around 40.5 deg C.
Exercise physiologist Fabio Comana, from the American Council on Exercise, told MSNBC that the body is not designed to perform yoga in extreme heat (over 40 deg C) and that doing so can damage proteins.
He said: "You may think it's purifying and cleansing, but you have to respect the physiology of the body."