Originally Posted by
CadenceCrazy
I maintain a ride database that captures three different and probably totally inaccurate calorie burns. One source is a heart rate monitor, the second Ride With GPS, and the third a formula I found somewhere on the web. Granted, none of the three are probably very accurate but the trend data for similar rides could have value. Surprisingly, the HRM and RWGPS numbers are usually extremely close, frequently within 75 cals for a two hour ride. Both devices probably use a very similar but still inaccurate algorithm. A power meter would be the gold standard but I don't put out enough watts to light a refrigerator and can't justify the expense. In any case, the scale doesn't lie.
The idea of trending is important and the fact that the HRM and RWGPS are close is interesting.
HRM based calories are not as accurate as an power meter but those who claim that the numbers are completely useless fail to recognize that it is an order of magnitude tool. Uncertainty is a given for order of magnitue tools and estimates. The claim to absolute accuracy isn't made and the numbers can be useful as an estimate, especially in the beginning of a project or effort, for trending or to keep track of diet and exercise for the sake or consistency.
Personally, I don't care if the numbers are 20% or even 50% off as long as they are consistent and the bathroom scale agrees. Once I've lost (or gained) some weight I begin to understand how much I can eat and how much exercise I have to do to lose, gain or maintain weight.
-Tim-