Essentially I’m asking why we didn’t evolve to function at higher temperatures, since it seems most efficient for infections.
Essentially I’m asking why we didn’t evolve to function at higher temperatures, since it seems most efficient for infections.
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The other parts of your body are not as efficient at 100 degrees, and your body doesn’t want to spend energy when it doesn’t matter to the success of your genes over the course of your life. It’s the same reason you don’t leave your oven on at 350 if you know you’re going to cook tomorrow: it’s wasteful until it becomes a higher priority.
Because there is more than just white blood cells in your body. Everything else (e.g. most proteins and enzymes) require a much lower temperature than white blood cells – they would just be boiled and you’d die.
It’s all about balance and that is the optimum temperature for the whole body.
Having a higher base temperature requires more energy, which means needing more food. So it’s a balance. And Mammals in general are already warm enough that the vast majority of infections will be dealt with without us noticing
Everything comes with trade offs – a higher core body temperature requires using more fuel, which requires taking in more calories, which requires access to more resources. Historically, humans encountered far more scarcity than abundance, so individuals who needed more resources tended to fare poorly compared to individuals who needed less resources when times got tough. That translated to less reproductive success over hundreds or thousands of generations.
In addition, other bodily functions are not as efficient or have issues of their own as body temperature rises, so there’s a trade off between fighting infections and (e.g.) avoiding seizures and things like that. Evolutionarily speaking, our body temperature is the product of all these different trade offs playing out over hundreds of thousands to millions of years.
A higher body temperature uses more energy, meaning that you’d need to consume more to keep it up. Evolution has min/maxed our body temperature to optimize the difference between how much energy is needed to keep it running and how much food can reasonably be eaten, with fever being an emergency mode for fighting out-of-control infections.
Cells in your body are formed from proteins, which are long strings of amino acids which fold into specific shapes in order to perform specific tasks. Proteins are very temperature sensitive, so some will perform their task better at specific temperatures, however once you start getting above 40-45 degrees Celsius, the bonds holding those proteins into that specific shape start to break, we call this denaturation.
Without those proteins doing their job, you die.
Keeping the body warm requires a lot of energy. If our natural temperature was higher, it would take much more food just to keep us warm as our living environment wouldn’t be any different. Also if our temperature would evolve higher, the viruses and bacteria would have evolved to withstand the same temperatures.
Cos temperature above ambient costs calories and calories come from food. so 2 physically identical animals but one runs at 2 c high. it translates to more calories than you would think cos it’s on all day every day.
Turn toaster on all day and see if electricity bill rises.
It’s worth noting that it’s not coincidence that white blood cells function best at a higher temperature than the rest of your body; fever is one of the most common responses to infection, so white blood cells are often going to be doing their job at slightly above normal body temperature. And in fact, the worse the infection, the more likely you are to have a fever.
If our base temperature was higher, it’s likely that our white blood cells would function best at a temperature that was even higherer.
Well it might be efficient for infections, but it might kill our cells too. Not to mention that to keep yourself at operating temperatures, you would have to increase your energy input as well and eat much more. Also sperm actually really hates higher temperatures.
Blood cells aren’t the key issue here, the chemistry of the human body works ideally at this temperature any higher and it can start to cause damage to the body.