Q. Is it true that I could actually burn more calories by exercising in a hot room?

Not really. Your calorie burn has more to do with how hard you're working, says Steven Blair, president and CEO of the Cooper Institute in Dallas. You might burn slightly more calories sitting in a hot room because your body has to work harder to cool itself off. But if you're exercising in extreme heat, you'll probably get tired more quickly and have to reduce the intensity or cut your workout short. This ultimately means you'll burn fewer calories.