I am confused when it comes to how many calories are burned during exercise for different machines. I usually do the Lifefitness crosstrainer machine and burn off about 600 calories in 45 minutes. When I jumped on the stairmaster today I was breathing and sweating much harder than I do when on the crosstrainer, but after 45 minutes it said I only burned off 450 calories. My question is what should I go by, what the machine says I burned off or what my body is telling me when it's pouring out sweat? Because it sure fills like I burned off more calories on the stairmaster than I did on the crosstrainer.