Will an athlete who runs for an hour at moderate pace and is not tired at the end burn more calories than an out of shape person who runs for an hour a way shorter distance but is exhausted at the end?
Assuming both have the same weight and such
What I want to know basically is if your body gets stronger will it need less energy to perform the same amount of work?
In: 1708
Basically, what determines calories burned is how much work you do, not the *percieved effort* and not the *aerobic effort*.
Running is tricky because people do actually substantially increase their running efficiency, but that’s biomechanical. So let’s pretend that you have two athletes who are the same size and weight and have equal *running economy* — how biomechanically efficient they are at running. However, one is much more fit than the other.
If your two athletes run at the same speed for an hour, they’ll of course cover the same distance. They’ll also burn the same number of calories. The less-fit one will have a much higher perceived exertion (“level of suck”) and the run will have been for him much more aerobically challenging.
If your two athletes run at the same level of exertion for the same length of time, then the more-fit one will go faster and will expend more calories. For two athletes of the same weight, for most running speeds, calorie burn rate is roughly proportional to running speed.
In cycling, we actually measure power put into the pedals directly. That’s not the same as the power a human has to put out to make that happen, but the efficiency for cycling doesn’t vary very much from one person to another (it’s around 22%), so it’s really easy to accurately compute calories burned from measured effort on the bike. For two athletes, doing 200 W for an hour might be an all-out, soul-draining effort for one and a walk in the park for another. It doesn’t matter — both will have expended just under 700 calories.
It’s the effort for sure. The body isn’t a simplified physics textbook problem. It has all kinds of inefficiencies and optimizations. Your mechanical motion is indescribably complicated if we want to completely describe it with physics formulae. And that doesn’t even include biological changes and adaptations over time. So no, your calories burned has a loose connection to the “work” being done. Whatever you perceive your effort multiplied by time yields a far more accurate accounting of calories burned.
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