Sleep Flushes Toxins from the Brain • Hacker News Board

Re: Sleep Flushes Toxins from the Brain

#41

Post by twistedpair » Fri, Oct 18, 2013, 12:24 AM UTC

comrade_ogilvy wrote: post #24

XorNot wrote: post #5

Earlier quoted context omitted.

The question on everyone's mind now is, can you bypass that need?

Probably not. If a lot of energy is being used in the clean up process, then the need for sleep is most likely driven by the physical advantages of sleep, not the advantage of using less energy or similar. Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more flui…

Too bad, 24 hour consciousness could help a lot of startups.

Re: Sleep Flushes Toxins from the Brain

#42

Post by j-g-faustus » Fri, Oct 18, 2013, 12:41 AM UTC

comrade_ogilvy wrote: post #24

XorNot wrote: post #5

Earlier quoted context omitted.

The question on everyone's mind now is, can you bypass that need?

Probably not. If a lot of energy is being used in the clean up process, then the need for sleep is most likely driven by the physical advantages of sleep, not the advantage of using less energy or similar. Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more flui…

It's an interesting choice from an evolutionary standpoint: At the time homo sapiens evolved, we presumably had saber-tooth tigers, tyrannosaurus rexes, abonimable snowmen (or whatever :) prowling the bushes around the place we slept.

If you were all alone, wouldn't it be a better survival trait to be groggy 24h/day than to be fully alert 16h/day and dead to the world the remaining 8h?

I've heard that there are species of fish (and possibly birds) that are awake around the clock; they deal by sleeping one brain hemisphere at a time, which leaves enough active brain to avoid obstacles and predators.

If humans never took that evolutionary road, does it mean that we are genetically disposed to social groups, i.e. "someone else is watching your back while you sleep"?

Re: Sleep Flushes Toxins from the Brain

#43

Post by cbhl » Fri, Oct 18, 2013, 12:42 AM UTC

twistedpair wrote: post #41

comrade_ogilvy wrote: post #24

Earlier quoted context omitted.

Probably not. If a lot of energy is being used in the clean up process, then the need for sleep is most likely driven by the physical advantages of sleep, not the advantage of using less energy or similar. Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more flui…

Too bad, 24 hour consciousness could help a lot of startups.

... until their users started being conscious that long too.

Re: Sleep Flushes Toxins from the Brain

#44

Post by jonny_eh » Fri, Oct 18, 2013, 1:06 AM UTC

jared314 wrote: post #29

mey wrote: post #25

Earlier quoted context omitted.

My reaction to this, it is very important to by well hydrated when sleeping.

Technically your brain is using cerebrospinal fluid not water, but the scientist was talking to a reporter, who was writing for the general public. So, something might have been lost in the translation.

But where does that fluid come from? I assume water (plus other nutrients) that was consumed earlier in the day.

Re: Sleep Flushes Toxins from the Brain

#45

Post by Scaevolus » Fri, Oct 18, 2013, 1:07 AM UTC

j-g-faustus wrote: post #42

comrade_ogilvy wrote: post #24

Earlier quoted context omitted.

Probably not. If a lot of energy is being used in the clean up process, then the need for sleep is most likely driven by the physical advantages of sleep, not the advantage of using less energy or similar. Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more flui…

It's an interesting choice from an evolutionary standpoint: At the time homo sapiens evolved, we presumably had saber-tooth tigers, tyrannosaurus rexes, abonimable snowmen (or whatever :) prowling the bushes around the place we slept. If you were all alone, wouldn't it be a better survival trait to be groggy 24h/day than to be fully alert 16h/day and dead to the world the remaining 8h? I've heard that there are speci…

Sleeping in one 8-hour block at night seems to be a recent invention.

http://discovermagazine.com/2007/dec/sleeping-like-a-hunter-...

"...the Ibans of Sarawak, 25 percent of whom are apparently active at any one point in the night."

Re: Sleep Flushes Toxins from the Brain

#46

Post by thaumasiotes » Fri, Oct 18, 2013, 1:12 AM UTC

j-g-faustus wrote: post #42

comrade_ogilvy wrote: post #24

Earlier quoted context omitted.

Probably not. If a lot of energy is being used in the clean up process, then the need for sleep is most likely driven by the physical advantages of sleep, not the advantage of using less energy or similar. Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more flui…

It's an interesting choice from an evolutionary standpoint: At the time homo sapiens evolved, we presumably had saber-tooth tigers, tyrannosaurus rexes, abonimable snowmen (or whatever :) prowling the bushes around the place we slept. If you were all alone, wouldn't it be a better survival trait to be groggy 24h/day than to be fully alert 16h/day and dead to the world the remaining 8h? I've heard that there are speci…

> I've heard that there are species of fish (and possibly birds) that are awake around the clock; they deal by sleeping one brain hemisphere at a time, which leaves enough active brain to avoid obstacles and predators.

Whales are known to do this; I imagine it makes breathing much less difficult.

Re: Sleep Flushes Toxins from the Brain

#47

Post by batgaijin » Fri, Oct 18, 2013, 1:38 AM UTC

I always wondered about how split-brain theory would work into this...

I mean there are stories of people with half their brain removed who are fully functional (I think? I can't find a source atm).

I wonder what would happen if half your brain could be on/off and switch?

Also you'd think that any mutation optimizing for time awake would have decimated the other creatures? I don't get how evolution has conquered everything but sleep.

Re: Sleep Flushes Toxins from the Brain

#48

Post by dbecker » Fri, Oct 18, 2013, 1:51 AM UTC

"The brain only has limited energy at its disposal and it appears that it must choose between two different functional states - awake and aware or asleep and cleaning up,"

Sure sounds like part of the wake-sleep algorithm, which is impressive given that the wake-sleep algorithm was named in the mid-90s.

Re: Sleep Flushes Toxins from the Brain

#49

Post by jared314 » Fri, Oct 18, 2013, 1:59 AM UTC

jonny_eh wrote: post #44

jared314 wrote: post #29

Earlier quoted context omitted.

Technically your brain is using cerebrospinal fluid not water, but the scientist was talking to a reporter, who was writing for the general public. So, something might have been lost in the translation.

But where does that fluid come from? I assume water (plus other nutrients) that was consumed earlier in the day.

True, but your body only produces 0.5 liters (~17 fl oz) over a 24 hour period, and has 0.15 liters (~5 fl oz) at any one moment. So, being well hydrated when sleeping might positively affect other systems, but the effect on your CSF would be negligible.

Re: Sleep Flushes Toxins from the Brain

#50

Post by meowface » Fri, Oct 18, 2013, 2:03 AM UTC

coolnow wrote: post #39

meowface wrote: post #23

Earlier quoted context omitted.

Many people experience hallucinations if they stay awake for periods longer than 48 or even 36 hours.

I think i believe this. A friend of mine is a virgin to late nights and all nighters. We were studying one night trying to cram for a test and communicating every so often on WhatsApp. At around 12AM, he told me he thought he was hallucinating. I laughed as he was only up for like 14 hours. He fell asleep shortly thereafter.

I can relate. I've only had two "all nighters" in my life, and felt utterly miserable each time.

Towards the end of both, I would develop minor visual hallucinations (seeing little things in the corner of my eye, etc.). 14 hours is a bit silly, though. 24 hours is probably the minimum for most people.