the brain burns more power when doing mentally exhausting tasks than at idle, so it makes sense to have to recharge mitochondria in there. (the 'more' is not huge, like 5% - so it also makes sense to be tired after a lazy day I guess)
Re:Sleep all comes down to the mitochondria
by HarHarVeryFunny on Wednesday July 30, 2025 @11:35AM
(#44735586)
But we're sleepy every night regardless of how much or how little we have done mentally during the day. Doing more work (mental or physical) than usual will make us feel more tired, but the basic need for the 24hr sleep cycle is there regardless.
We fundamentally sleep at night based on circadian rhythm (evolved from earth's 24hr day), not based on activity level. We do also feel tired after a strenuous activity, but recover after a little rest and nutrition - this doesn't appear to be the same thing as the fundamental need for sleep.
Re:Sleep all comes down to the mitochondria
by kridsdale1 on Wednesday July 30, 2025 @12:20PM
(#44736200)
The body expends 2000 calories of energy (via mitochondria) simply to be alive, even if you lie in a hospital bed and are unconscious. You do a marathon’s amount of work every day. You need to sleep to deal with that.
Re:Sleep all comes down to the mitochondria
by HarHarVeryFunny on Wednesday July 30, 2025 @12:57PM
(#44736622)
We're also alive when we're asleep ... The difference between being asleep or awake lying on the couch seems to have more to do with reduced/different mental activity than energy usage.
Being unconscious, or in a coma, in a hospital bed is more akin to being asleep, which is why you can be in a coma for years without dying.
Re:Sleep all comes down to the mitochondria
by BobaFloutist on Wednesday July 30, 2025 @03:44PM
(#44738704)
And frankly, while a long day makes you feel more tired, I don't know that having to focus a lot or working out a bunch really makes me want to go to bed noticeably earlier.
Re:Sleep all comes down to the mitochondria
by pitched on Wednesday July 30, 2025 @03:49PM
(#44738755)
One of the ways this electron leak happens (from the chatGPT) is that fuel (NADH) exceeds energy demand (ATP). So a good way to push off the mental need for sleep is to get your body tired. So the processes aren’t quite perpendicular.
It seems the mental need for sleep comes from the brain needing offline (no sensory input) downtime for "housekeeping" activities - perhaps essentially organizing and filing away the day's short-term memories.