A group of 25 men and women fold their sweat-drenched bodies forward, clasping their heels with their hands. They’re in a room set to about 41 C.
A young woman, her shoulders shaking, breaks from the pose and lies down on the yoga mat under her feet. Every inch of exposed skin is beaded with perspiration that won’t evaporate. She looks overwhelmed.
The booming voice of a svelte yoga instructor cuts through the oppressive heat. “Maybe you feel a little bit nauseous sometimes. Maybe you feel a bit dizzy. Good. It’s working. You’re getting all the toxins out,” she says.
At Bikram Yoga Bloor in downtown Toronto, students engage in what seems like athletic masochism (the practice’s founder, Bikram Choudhury, refers to his studio as a “torture chamber”) to “release their toxins” and treat myriad conditions including asthma, carpal tunnel syndrome and hypertension.
Students Ann Jervis, 57, and Hayley Dineen, 23, remember unpleasant first experiences with Bikram yoga, but stuck it out because of the perceived advantages of the practice.
But some health professionals question the efficacy of the trendy style of yoga, practised for 90 minutes in stifling heat.
“As a scientist, I wouldn’t say there’s a huge stock in sweating out your toxins,” says Stephen Cheung, the Canada Research Chair in Environmental Ergonomics, whose area of expertise is heat stress. The body only releases them through sweat to a very limited extent, he says.
The extreme temperature and humidity in Bikram yoga and its less regimented spinoff Moksha yoga can be risky for those with heart conditions, as well as for those with low or high blood pressure in the normal range, says Nieca Goldberg, medical director of New York University’s Women’s Heart Program.
Review sites such as Yelp, yoga forums and Twitter are rife with tales of students feeling dizzy, passing out and being tended to by paramedics.
Bikram is no stranger to controversy: About six years ago, when it first gained popularity in North America, participants complained of injuries and pulled muscles. Doctors blamed the hot conditions, which sometimes allow students to stretch too deep.
But the dizziness and blackouts are of concern to Dr. Goldberg, a cardiologist, because hot yoga’s proponents give students the impression that light-headedness is to be expected.
When Sheila Madsen attended her first Moksha yoga class in Toronto two years ago, she was overwhelmed by the heat and felt dizzy. She continued, because an instructor told her things would get easier. She says that since she could get through tennis practice and Pilates class without difficulty, she wondered why she was struggling so much at Moksha yoga.
“Some people do well in high levels of humidity. I do not,” Ms. Madsen, 64, explains. “I couldn’t get my heart rate down sometimes for half an hour, which is really dangerous.”
She would go into “child’s pose,” a resting position, but the room’s conditions made relaxing difficult. On four occasions, she left the 39 C room to recover. Then she quit.
The science behind fainting is simple. “Your blood vessels normally expand to go to your exercising muscles,” Dr. Goldberg says. “There’s an even magnified response when you’re doing it in a very hot environment. That’s taking blood away from the blood vessels that are going to your brain, so you faint.”
She has treated otherwise healthy patients who fainted in hot yoga classes.
Dana Moore, co-owner of Bikram Yoga Bloor, says there have only been a few cases of fainting in the studio’s two-year history. Instructors, trained in first aid, usually spot warning signs and guide students down onto their mats. And, as at all reputable studios, students must fill out a form disclosing any injuries, ailments or health conditions. Staff call new students to see how they’re feeling within two days of their first class.
