From Chelsea, Age 17 - 07/08/05 - IP#: 24.210.201.xxx  Click here to reply  
Ht. 5'6, A little something you may not know:
"Cardio work" is basically anything that makes you sweat: running, stair-climbing, sports, stuff like that. For a cardio workout to be effective, though, your heart rate has to increase and stay high for at least 20 minutes. At the 20-minute mark, the body stops running only on its stored energy, and it turns to its fat deposits (and all of your exercise over 20 minutes will pull from that stored fat). I suggest that you don't bother yourself with insignificant details like "how does this happen?" It's magic. All that matters is that it really works.