If you've got a serious medical condition, especially a heart condition, aerobics is not for you. The bouncing and strenuous activity involved can make your condition worse. If you have any doubts, consult with your doctor before you attempt your first aerobics workout.

Most of us think of Jazzercise and similar dancing-style classroom exercising when we think "aerobics," but the truth is that the term covers a wide variety of strenuous exercise involving your cardiovascular system: running and swimming are both aerobic activities.

Your aerobics program is useless if you go home and eat a quart of ice cream afterward. To lose the maximum amount of weight, you'll need to make a sincere effort to plan your diet carefully, and you'll have to exercise some willpower to keep from sabotaging yourself.