New Study Analyses The Safety Of Bikram Yoga

In the study, men tended to display slightly higher heart rate increases compared to the women. Getty Images

You might do Bikram yoga in a 41-degree room because it’s a “cool” workout.

Or because you like the challenge. Or because you feel the heat can improve your muscle elasticity, making it easier for you to bend into poses that work your legs, core, shoulders, and back muscles.

But is this practice actually safe? In a small new study commissioned by the American Council on Exercise (ACE), researchers found that Bikram yoga participants reached a high core temperature of 39 degrees or above.

That can be scary when you consider the risk for heat-related illnesses increases when body temps reach 40 degrees.

Here’s a closer look at the study: the 20 healthy volunteers—seven men and 13 women — were all regular practitioners of Bikram, so they were familiar with the 26 standard poses and were fairly used to working out in 40-degree rooms with 41 per cent humidity.

The subjects swallowed a core body temperature sensor and wore a heart-rate monitor during a standard 90-minute session. Temperature readings were taken every 10 minutes and heart rates were measured every minute.

Out of the 20 participants, one man reached a peak core temperature of 40.1 degrees and another seven people exceeded 39. “But none of them displayed or reported any signs or symptoms of early heat illness,” says Dr Cedric Bryant, the chief science officer at ACE and the expert overseeing the study done by researchers at University of Wisconsin—La Crosse.

“My guess is that they were pre-acclimated to the hot and humid environment,” Bryant says.

While heart rates fluctuated throughout the class depending on the difficulty of the pose being performed, the men tended to display slightly higher increases compared to the women.

(To jack up your heart rate and incinerate fat, check out 10 Exercises That Burn More Calories than Running.)

That’s not to say that yoga is more dangerous for guys than for ladies, Bryant says. “It could just be due to the fact that, typically, women tend to be more flexible than men.” So men might have had higher heart because they were outside of their comfort level when reaching and holding the more difficult poses, he says.

Dr Lawrence Phillips, an assistant professor of medicine and physician of cardiology at NYU Langone Medical Center who wasn’t affiliated with the study, is less sure.

“The study shows reason for concern with some core temperatures going up to those levels,” Dr Phillips says. “Especially because, in this study, we’re unable to determine what factors would make core temperatures increase so much in some people and not others.”

Bryant says Bikram is still a safe and beneficial workout. But because the study was done in people who were already proficient in Bikram, beginners may not be quite so acclimated.

If you’re thinking of trying a class, drink 473 to 710ml of fluids within two hours of the start time. Bryant recommends a sports beverage like Gatorade or Powerade to help replace electrolytes. Then, to stay hydrated during the class, aim to have an additional 120 to 180mls every half hour and another 473 to 710mls after the class, Bryant says.

And don’t feel discouraged if you can’t complete the full 90-minute session or need to take a break between the poses.

“If you notice yourself experiencing any early warning signs—like light-headedness, dizziness, mild headaches and mild nausea—those aren’t things to try to power though,” says Bryant. “That’s your body trying to give you clues that you really need to find an area to cool yourself and get some fluid.”

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