You’ve heard: Heated workouts are better for you because you burn more calories.
The truth: “This is just an illusion. You burn more calories when you work harder,” says Liz Neporent, a health and fitness expert and national spokesperson for the American Council on Exercise. Sweating more might make you think you're working harder, but in order to burn more calories, your muscles have to put out more effort, your heart has to beat faster, and your breathing rate has to increase too, Neporent says.
What about when the scale says you’ve dropped a few pounds after a serious sweat session? “You will initially lose more weight when you sweat more,” Neporent says, “but as soon as you drink something, you replace the water weight.”
As for claims that the heat will give you a better stretch? That might not be such a good thing, says Amy Dixon, a celebrity trainer and exercise physiologist. “Not only can exercising in the heat be dangerous, it could cause you to get so deep into certain [yoga] poses that you might have to call a friend to help you get out of them!” Yikes!
Bottom line: It’s one thing to get hot and sweaty because of the intensity of your workout, but there is no need to seek out extra, external heat sources in order to burn more calories or get a deeper stretch.