heart rate and calories burned while bike riding?

Hello,

I have a question about heart rate and calories burned while bike riding. If the heart rate of the rider is the same at different speeds, then are the calories being burned the same regardless of the speed? In one of Bicycling Magazine's books, there is a table that shows how many calories one will burn according to speed and weight. What the table says is that the higher the speed of the rider the more calories he or she will burn per minute. In addition, other calorie calculators I have reviewed say the same thing. (I have found that the Bicycling Magazine table will usually show a higher amount of calories burned while riding a bike than most other calorie calculators will.) Of course, the more the rider weighs the more calories she will burn.

The situation: Let us say of the rider that her heart rate zone is between 105 and 140. She rides her bike for one hour. During this hour, her heartbeat is always within the heart rate zone. During the hour of biking, her speeds are as fast as 21 mph on the downhills and as slow as 5 miles per hour on the uphills. At the end of the ride, she averages 8 mph for the hour.

Here is my question: Will the same amount of calories be burned at different speeds as long as the heart rate stays constant or at least in the same limits of the heart rate zone? For instance on this ride the same rider may have a heart rate of 135 beats per minute at 8 miles per hour. At 12 miles per hour, the heart rate is 135 beats per minute.

Peace,

No, heart rate is a poor measurement of relative calories burned. Heart rates are affected by a lot of factors which have nothing to do with exercise intensity i.e. emotion, medication, amount of sleep, etc. The amount of calories burned is basically related to mass X distance, though in cycling factors such as wind resistance and the mechanical efficiency of the cycle come into the equation. Find a good calories/mile estimate for your weight at the speed you typically cycle. Some days it will be a little more and some days a little less, but it will average out.

For instance on this ride the same rider may

I don't understand this statement.....but basically use heart rate as a training tool and to assess your aerobic improvement. Forget about correlating it to calories burned.

JAK

Heartrate when measured against known exhertion is a good indicator of relative fitness but there's no way to directly link heartrate to calorie consumption. Exhertion is the predominant indicator of calorie consumption.