For me, a 77 kg male, it's about 1100 calories. That's about 550 kcal per hour. Not as much as a running, but still a pretty good amount. I put the heart rate monitor on during practice last night to get an idea of how many calories were being burned. It's a rough estimate for sure. I was just curious. My max heart rate was 165 and the average was 128. Some people have mentioned that I look like I've lost weight and I think they are right. I do look like I've lost weight, but I haven't. I the full body exercise I'm getting from doing Karate is helping my get leaner. At least, I hope it is. We use pretty much all of the muscles when doing it. You are pushing and pulling and swinging your arms in all different planes of movement. It uses your shoulders, your triceps, your biceps, your forearms, your legs in the deep shotokan stances, jumps, lunges and kicks, and our core muscles as you twist and turn your body and quickly as you can. The warm-ups get your heart rate up as well as the sparring and the kata. It IS good exercise.