I have a Polar FT 7, which is pretty basic. I came into HRM's and more aggressive bicycling through weight loss. I lost and have kept off for more than a year about 47 pounds.

Here's the news: As you become more conditioned,your calorie burn falls. Just ain't fair. But if I understand the physiology correctly, being more physically active kicks up your basal metabolic burn somewhat. You benefit from being more active and less sendentary.

I used the weight loss web site Calorie King and they have estimators for exercise (you can eat back calories burned with exercise). The commonly accepted scuttlebutt was that the estimates were high and the numbers you got with an HRM are "more accurate" and uniformly lower than the estimates. This has tended to be my experience also.

But they are really scientific best guesses, though I think they are not all wrong.

With exercise I have seen my resting heart rate drop. I did an estimation of body fat at my local YMCA (not the gold standard,which is an immersion test).

But with my new bike (did I mention I have new Trek Madone?) my plan is to work on cadence and then I will be interested to see if this kicks up my calorie burn.

Try not to focus on one number. Look at a constellation of data. There is no doubt that the "king" of calorie burn exercise is running. But I like biking. And that beats being a couch potato any day.