Effienciency of body muscles?

Question

Human body sweats a lot more when we run upstairs,
than when we run downstairs.

What upper limit of efficiency of muscles does this fact imply?

Answer 1

If you sweat, most of your output goes to evaporating the sweat instead of getting up the stairs. Take it easy, and you'll convert a higher percentage of output to the potential energy of your body in Earth's gravity field. Some portion of that can be converted back to chemical energy when you come back down, but the energy you lost to sweat can never be recovered.

The upper level of efficiency is not that obvious; it happens gradually. You perspire, even if you don't sweat; sweating is just a less efficent kind of perspiration. It becomes much more inefficient when drops of sweat fall off without evaporating. The purpose of sweating is to keep your body temperature within safe limits. If your body temperature rises above about 101 deg F, you will start sweating like crazy; that is the beginning of heat prostration, which is extremely dangerous; if you don't cool down soon, you die; that is really inefficient.

Of course, energy conservation isn't the only meaning of efficiency. If you're being paid to run up and down the stairs, you can probably earn money more efficiently by running 'til you drop.

Answer 2

1

Answer 3

About 3/4 of the energy used by muscles ultimately becomes heat. Going up stairs, fighting gravity, requires more energy--hence more heat is released. The fact implied is that it takes much greater energy to go up stairs than down.

Answer 4

No clue, except that it has to do with gravity helping going down stairs and the body's muscles pulling against gravity going upstairs....plus different muscles are used.