(Note: I’m not talking about FFI, but healthy people.)

It’s said that we need sleep because waste products, such as adenosine (which is a CNS depressant) build up in our brains while we’re awake. When we sleep, the glymphatic system activates and flushes it out. Too much adenosine is known to cause a slower heart rate, the body temperature to decrease, immune system to weaken, hallucinations, and more.

I read about how a Chinese guy (in 2014 or 2012?) deliberately stayed awake for 11 nights with no sleep at all to watch the world cup, and he died. The articles said he died of sleep deprivation.

Here’s the part which confuses me. I understand why too much of a CNS depressant waste product in your brain would be deadly, since it’d supress vital functions such as breathing, heart rate etc. I’m just wondering why it wouldn’t make you automatically pass out and sleep, long before it got to that level as it’s something which very gradually builds up in your brain the longer you’re awake.

  • thebestaquaman@lemmy.worldEnglish
    2·
    1 day ago

    I can actually imagine that evolutionary pressure could favour being able to kill yourself from sleep deprivation. Our ability to deny ourselves sleep is of course a result of evolutionary pressure, where people that were able to keep going for days on end without sleep to survive a crisis outcompeted those that collapsed from sleep deprivation and passed out.

    If we extrapolate to even worse crises, I can imagine that those who were able to keep going while carrying or protecting their kids or family until they died could have an edge over those that passed out from sleep deprivation, and died due to whatever they were staying awake to survive from. In short, that there are situations where it can be advantageous (from an evolutionary perspective) to be able to push yourself to the point of death, while ensuring that your kids survive.

    I have no research to back this up, but I can imagine that humans could have evolved the capability to kill ourselves from sleep deprivation.

    Another possibility (that’s kind-of mentioned by others here) is that once you go past a certain point of sleep deprivation, the parts of your brain responsible for making you sleep essentially stop working properly. If we assume that historically, it was extremely rare that people got to that point, there would be very low evolutionary pressure to fix that issue (i.e. make us pass out before dying). In that case, this could be one of the many situations where we have an attribute not because it’s advantageous, but because it’s not disadvantageous enough to be selected away by evolution.