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GeriatricZergling t1_iuhvqp2 wrote

The fundamental understanding is hard to find, but simple: our metabolism is broken, badly, as a baseline, and we make it worse to have a fever.

It doesn't cost anything near what we pay to run a body of our size. We know this because everything with "cold blood" does so for literally 10% of the cost (normalized for body weight and temperature).

Where do the other 90% of our baseline calories go? Heat. Specifically, we poke holes in the membranes of our mitochondria (via uncoupling proteins) to make them less efficient. This means we burn more energy to get the same ATP (cellular energy molecule), the rest of which is heat. This, in turn, heats our body and lets us be "warm blooded", at tremendous metabolic cost. To get warmer, we simply increase the number of these proteins. There's also diet drugs that do this, but they're incredibly dangerous because you can't plug the holes once they're made, you just have to wait for the proteins to break down.

Incidentally "cold blooded" species can get fevers too - pyrogens prompt them to bask more and get to hotter temperatures, a sort of "behavioral fever".

For pendants, note the quotes around "warm blooded" and "cold blooded".

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Catatonic27 t1_iui78du wrote

>There's also diet drugs that do this, but they're incredibly dangerous because you can't plug the holes once they're made, you just have to wait for the proteins to break down.

I always wondered if that were a thing. It always seemed to me like an excellent way to burn calories. I grew up and currently live in Vermont where the winters get very very cold and it's well-known that you have to nearly double your caloric intake if you're going to be outdoors in cold temperatures for extended periods of time. Especially doing a vigorous activity like skiing or snowboarding on a blustery day, it's frankly INCREDIBLE the sheer amount of energy the human body can cough up when it's well-fed and the need arises. I tracked myself as burning like 7k calories in a single day once.

Likewise, just going on a short walk can sap an incredible amount of energy from your body if you're not dressed well in poor weather, and it can take several hours and several good meals to get your energy level back up so it's easy to imagine that a significant amount of your body's energy budget goes to keeping you warm.

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