Bikram yoga is the hottest trend in exercise -- literally.

Bikram involves traditional Hatha yoga-style postures, with a twist. They're performed in a room heated to sauna-like temperatures.

Participants drip with sweat as they bend and stretch in a studio heated to about 38 degrees Celsius. They hold each of the 26 different positions for about 20 to 30 seconds each and rest between postures.

"I love it, it's great, it's fantastic," says Vancouver Bikram student Mina Hayes. "I'm addicted."

This particular style of yoga, known as "hot yoga," was developed in India by Bikram Choudhury. He brought it to San Francisco in 1973, and franchised the brand. Now studios teaching Bikram are heating up across Canada.

The high temperatures are meant to simulate the heat of India, to warm the muscles in order to promote flexibility, and to stimulate sweating to flush toxins out of the body.

"It helps burn fat more quickly, it elevates the heart rate, it thins the blood, and clears the circulatory system," says Bikram instructor Lisa Pelzer.

But medical experts say the heat could dangerously strain the body.

"It can damage your kidney, liver, and cause heart attacks," says Dr. John Blatherwick of the Vancouver Health Board.

The problem is that students can quickly become dehydrated from the intense heat.

Pelzer admits she's seen the side effects, but claim they're a sign the yoga is working, and not of any medical danger.

"I've had students throw up. Quite often some people may feel a little dizzy or nauseous and that's just a sign your body's cleansing itself, releasing toxins," she says.

Until the verdict on the safety of Bikram comes in, people with health concerns should consult a doctor or just chill out with more traditional yoga styles.