Going by my fitness tracker, a 1-hour 900kcal gym session is absolutely intense. On the few times I've hit that mark, I'm laid out on the ground and probably ne

Going by my fitness tracker, a 1-hour 900kcal gym session is absolutely intense. On the few times I've hit that mark, I'm laid out on the ground and probably need to take it easy the next day. More realistically, I hit 600-700kcal per session.