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230 points mdp2021 | 2 comments | | HN request time: 0.488s | source
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avar ◴[] No.41868092[source]
This article doesn't even try to address what I feel is the deeper and more interesting question (but probably one that can't be answered): Why is it that horses, cows, giraffes and birds have all had to come up with a purely passive solution of "locking" themselves in place, either via their joints (for the four-legged), or via the tendon mechanism described here for birds?

I.e. why wasn't in simpler in evolutionary terms to come up with some mechanism where 1% of the brain was dedicated to the relatively simple task of "station keeping", while the rest of the brain could benefit from sleep?

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roywashere ◴[] No.41868150[source]
Just as we can still breathe and digest food while sleeping!
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mr_mitm ◴[] No.41868760[source]
We can even adjust our sleeping position while sleeping, possibly to avoid bedsores? But perhaps avoiding falling requires more processing power.
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johnisgood ◴[] No.41868809[source]
Yes, adjusting our sleeping position has to do with the sensation of pain, a stimuli (pain, discomfort, pressure points) that cause most individuals to reposition during sleep, i.e. it is the sensation of pain from pressure buildup that triggers the need to move during sleep. You are right, it is to prevent prolonged compression of tissues, to avoid bedsores, nerve damage, etc.

That said, this is not the whole story, because there are people with a rare genetic disorder called CIPA which completely prevents the feeling of pain, but they still reposition themselves, so besides pain, it is muscle fatigue (that prompts subconscious movements), autonomic reflexes, and well, sleep cycles or phases also lead to the body shifting positions unconsciously.

In any case, people with CIPA are at a much higher risk of developing complications related to immobility because they do not experience the typical discomfort (pain) that triggers movement.

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Agentus ◴[] No.41869071[source]
I can do more than that. I used to wake up sweaty half the time from sleeping as child. Now that never happens as an adult, i instead wake up with my sweater mysteriously taken off. I wish sleep self would learn to put a sweater on if it turns cold though.
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glxxyz ◴[] No.41870790[source]
I swear I used to be able to switch off my alarm clock while still fully asleep
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1. mr_mitm ◴[] No.41871452[source]
Must be why there are apps that make you solve a math problem or take a picture of your bath room to turn off the alarm.
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2. fennecbutt ◴[] No.41909213[source]
It's exactly what I use "alarm clock xtreme" or whatever it's called. Math puzzle, retype or even scan barcode to stop alarm. It has been invaluable, especially as you can change difficulty, I found out even half asleep I could do basic addition etc...