Someone tell me what this is about? I've seen it on machines all the time, and never really thought about it till now. How the heck does doing a cardio exercise at only 65% burn off more fat than doing it at 85% or more? It doesn't make sense. In order for you to turn the treadmill, or spin the elliptical machine, or climb the stairclimber, it requires a certain amount of energy to make it go one rotation. So the more rotations you do, the more calories you should burn. Whether you are doing it at a slow speed, or if you're doing it fast. So why do charts on these exercise machines still print this? Is there any truth to it?