Similarly, what are the physiological processes of becoming tired? We know that certain neurotransmitters can increase or decrease our being tired, but what is it and why did it evolve?
The nervous system removes various waste products during sleep. For that to happen the glial cells contract and expand. They cant do that while you are awake, well maybe they could but it would probably not go very well since they handle a substantial amount of cognition during your waking hours too. Hence you have to sleep so that your body can carry out the trash. Like a big frivolous party where the cleaning ladies have to wait for the party to end before they start cleaning.
There’s no biological evidence of any metabolic wastes that are purified during sleep. The human brain doesn’t “rest” while sleeping anyhow – it is more active asleep than awake.
However, it needs to disable your limbs (therefore sleep-paralysis) and senses to conserve energy while resetting and recharging itself. Dreaming is our head’s editing floor.
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