Originally Posted by
DrIsotope
A calorie number based on heart rate might as well be randomly generated. Everything affects heart rate. Power is power.
^this.
I was shocked when I was looking at the calorie burned numbers from 3 different bike computers a few years ago. They varied by almost 100% method to method/computer to computer. If you want reasonably accurate caloric burn numbers that track your effort, you pretty much need to use a power meter. If you are, say, trying to lose weight by managing calories and you use some of the computers and their algorithms, you're going to gain weight at a rapid pace by using some of the methods out there.
J.