Watt Calculation

[Howard N]

This all seems kind of moot to me. After yesterday's short erg session my Polar heart rate monitor said I used 242 calories, my PM3 on the erg said 247. That's close enough for me. Truthfully, I wonder if either is anywhere close to the amount of food calories my body actually burned.

[Citroen]

Truthfully, I wonder if either is anywhere close to the amount of food calories my body actually burned.

Since (k)calorie measurement has little basis in science, probably not. They measured calories by burning food in pure oxygen. Humans don't do that when we convert food to glycogen and fats. Also my metabolism is probably wildly different to yours. Therefore it becomes a complete nonsense (store it with 220-age in the pseudo science box).

We're using calories as a proxy for watts (simple maths to convert) so we'll get consistent numbers from the PM3. With your HR watch it's using HR over time (with some other factors like age) to estimate calories (again there'll be a formula for doing that).

As a personal trainer said to me, "Set someone off on a CV machine with a goal of getting the indicated calorie number to reach 100 and they'll have to do some work to get there".

[OarConsequences]

If you want to track calorie expenditure there are now devices which can do so very accurately. Look up Body Bugg or other electronic calorie counter devices. They strap on your arm and actually do physiological measurements. These are a vast improvement over estimating by multiplying time at an exercise by a guesstimate of calories per hour like what used to have to be done. Just be warned that the other half of accurately tracking caloric expenditures is accurately tracking caloric intake which is harder to do that strapping a monitor on your arm.