First, let me apologize for resurrecting this old thread.

I am not concerned about calories, in general, with respect to my cycling. However, my Polar M52 HRM changed my life by showing me how few calories I burned during strenous workouts. BTW, I don't work for Polar.

The M52 allows you to input your age, gender, weight, height and activity level (high, med, low). Then using this information and the heart rate data from your workout it will give you calories burned - during the workout and at the end.

I believe it to be fairly accurate. . . or at least, accurate enough if you care about calories. My observations, based on 2 years with this HRM:

1) Calories consumed is totally dependent on the intensity of the workout. In my case, while on my wind trainer with no interruptions, 500 calories per hour is a pretty good zone 2-3 workout, 700 - 800 calories/hr is a hard zone 4 workout, but in an XC race last September I burned 1,000 calories in one hour. Yes, I was trashed for two days. I'm confident that were I running for an hour in the same HR zones, I would have burned the same calories.

2) After observing how hard it is to burn 500 to 1,000 calories in a workout, I changed my eating habits and dropped 30 lbs. I had always thought I was burning a lot more calories. Basically, I had to kill myself for an hour to burn off a Big Mac, fries and a Coke.

3) Now the calorie counter feature of the HRM is not of much use to me, I'm ready to move on to a new HRM.

4) As my fitness improved and I lost weight my calorie burn stayed fairly constant, but I went a lot faster.

5) Don't compare sports, compare intensities.

I read that Lance's average HR for a flat stage in the TdF is 128bpm. Keep in mind that he's in the draft, but 128 is in my recovery zone and I'm 42 yrs. old. I'd bet he's not burning 400/hr at that level of intensity.