A friend of mine has suggested in our conversations about exercise that I "cheat" while cycling. His belief, which I believe is uncorrect, is that when I ride a bike for exercise and I coast a little bit here and there that I'm no longer exercising/burning calories, thus I'm technically cheating. He says when he walks for 3 miles he has to keep moving. If he stops walking he can't coast and is no longer moving forward therefor there is no cheating.

I've kinda tried to explain to him that because of Newton's Laws Of Motion that every action has an equal and opposite reaction. Thus if I am indeed coasting on flat ground, I've already applied the effort to the pedals and burned the calories to propel the bike forward. Thus my stance is coasting is not cheating in regard to exercise.

Does anyone know the math for this or have a formula? I'm curious to know who is right, but my guess is I am.

EDIT: I meant to post this in the General Discussion area, so please feel free to move it there.

Also, when my friends says "cheating" I'm fairly sure he means "no longer burning calories" and not breaking some type of rule.