My Fitness Pal

[goldfinch]

It is fairly easy to figure out how many calories you take in, but it is almost impossible to figure out how many you burn outside of a lab. All the tools are not accurate. The closest is probably a power meter. The next closest probably a heart rate monitor. The problem is that there are too many variables and when you estimate so many variables there is potential for error stacked on top of error leading to sometimes wildly inaccurate results. You might enter your age, sex and height into a heart rate monitor but the monitor still doesn't know your fat mass, personal metabolic rate, individual heart rate differences, your general fitness and health, your stress level, the air temperature (heart rate goes up when it is hot), and even your adaptation to a type of exercise, all of which can effect calories burned or the estimate of calories burned.

Calculators that estimate without heart rate, like online tools, are so inaccurate as to be useless. They add the variable of guessing your effort. Twelve miles an hour may be easy effort on the flats and a bear on the hills. Sixteen mph may be hard effort for some and easy for others, or hard in a head wind and easy with a tail wind, hard on a rough road, easy on a smooth. Easy on the road bike and next to impossible on a mountain bike. Etc.