23 ms·

Researchers suggest that R.E.M. sleep serves to warm the brain

291 points by dnetesn 8y ago

rubidium 8y ago
Natural question follows: can humans train ourselves to do the same as animals in water? Live a bi-phasic life where creative / analytical sides of brain each get to "sleep"?
- newnewpdro 8y ago
  Humans are animals
  - ivanhoe 8y ago
    Sure, but we're not "animals in water" as OP wrote? Perhaps reading the full sentence before commenting? Just an idea...
    - newnewpdro 8y ago
      I read the entire sentence, but had not yet read the article, and had not had my morning coffee yet. After looking through the article, given the context it's pretty obvious they were probably referring to Amphibians. The sentence is poorly worded, because when a human is in water, it's an animal in water. Through that lens alone it makes no sense.
- SimonPStevens 8y ago
  The character Kraiklyn in the Iain M Banks novel Consider Phlebas has had enhancements to his brain to be able to do this.
- alfredallan1 8y ago
  It is not the same thing, but some people learn to switch between analytical and creative activity. I am many more could, if they tried hard enough.. Of course, there’s no recipe for how to learn this sort of thing which makes it a lot harder.
  - creep 8y ago
    True. I go through phases like this. For two whole weeks I will write (creatively) and draw, and then I usually find there is a day or two when I can't seem to do much of anything useful besides menial tasks and watching stupid videos. Then I go through another two weeks of analytical stuff-- reading, catching up on work (programming and mathy stuff), and doing planning for my writing. I can control it, if necessary in a day. The urge to do one thing or another is an intense "mood" for me (which, like I said, normally has a two-week period). This indicates some kind of synchronization, so if I want to switch I use musical triggers: airy, melodic music for creativity, and beat-heavy, algorithmic music for analytical activity. I only need to listen to the music for a few minutes to switch, and of course it sometimes doesn't work but I don't know of any other triggers. Possibly going out for a short walk could do it too? Meditation?
- gus_massa 8y ago
  Probably nobody knows, but I guess these animals have an special adaptation to make bi-phasic sleep possible. I guess that to evolve it you only need to keeping an isolated human population for a few million years were you kill at random some of the one that are sleeping, to encourage swallow sleeping and later bi-phasic sleep. Another possibility is trying a genetic modification, but it's impossible with the current technology and knowledge, perhaps in the future ... If you want to have a peek, you can read about the Wada Test https://en.wikipedia.org/wiki/Wada_test https://en.wikipedia.org/wiki/Wada_test . (And somehow related https://en.wikipedia.org/wiki/Split-brain https://en.wikipedia.org/wiki/Split-brain )
- vertexFarm 8y ago
  The creative / analytical dichotomy of the brain is a myth I'm afraid.
- djsumdog 8y ago
  It would depend on how this evolved in the water mammals researchers have found this in. Maybe some land mammals do the same thing, we just have preformed this type of experiment on them yet. If it does appear in humans, it'd probably be best to study those with extreme insomnia or people who claim to have very short sleep patterns (<2 hours a night) or maybe those who are narcoleptic (the other end of that scale).
  - darkerside 8y ago
    So we need a volunteer to put the electrodes on the hippopotamus?
Smaug123 8y ago
My first reaction was that it seems so inefficient to bring the entire computer online just to maintain its temperature - which could be controlled physically using blood. But couldn't we test this by artificially keeping the brain warm and seeing what sleep patterns emerge?
- creep 8y ago
  As an anecdote, I always have intense dreams with fever. I'm prone to kidney infections so I experience this often. My head is clearly very warm, my brain swells a little with the heat, and my dreams are clear and intense.
  - spydum 8y ago
    this would seem likely because you aren't sleeping well or deeply, hence able to recall the dreams.
    - creep 8y ago
      I usually recall my dreams, fever or not. There is a marked difference between them.
- stepik777 8y ago
  > it seems so inefficient to bring the entire computer online just to maintain its temperature In what sense is it inefficient? In terms of energy 100% is converted to heat anyway
  - manmal 8y ago
    Some of that should be converted into lowering entropy (building neural structures etc) so I don’t think 100% escapes as heat.
- iforgotpassword 8y ago
  thats what i thought. seems easy enough to do. I'd like to see more evidence to support that theory, I'm rather sceptical. i was remembered of that very rare condition where your brain cannot ever enter the deeper sleep states. these people usually die rather soon after onset of exhaustion. what has been confirmed through these people is that narcotics dont help at all. while you can ise it to make them 'sleep' long enough, it's not helping with the condition. so brain warming cannot be the main reason for REM, if it's one at all. edit: fatal insomnia is what i was referring to.
maxander 8y ago
You expect a future where brain implants will be tiny computers that make you smarter, but perhaps instead you get a future where brain implants are tiny heating coils that make you wake up earlier.
- manmal 8y ago
  I‘m pretty sure I won’t have any kind of brain device installed, no matter the upsides. No upgrades for that hardware!
  - Jeff_Brown 8y ago
    I feel the opposite. As soon as it's possible to replace biological neurons with artificial one, even if they aren't perfect replicas, I'm in. I'm pretty sure the mind is an emergent phenomenon robust to slight variations in the lowest levels of hardware, and I'd like to live for billions of years. (And if the tech lets you process faster, it could feel like trillions.)
dpods 8y ago
I'd recommend the book "The Promise of Sleep" [0] for anyone that's interested in learning more about sleep. The author basically pioneered the sleep medicine field and was at the University of Chicago in 1951 when R.E.M. sleep was discovered. [0]: https://www.amazon.com/Promise-Sleep-Medicine-Connection-Happiness/dp/0440509017 https://www.amazon.com/Promise-Sleep-Medicine-Connection-Hap...
- toomuchtodo 8y ago
  Thanks, purchased! Sidenote: The book recommendations on HN are always top notch.
- Styrke 8y ago
  I would recommend reading Why We Sleep by Matthew Walker instead. [0] The Promise of Sleep is an okay book, but it is almost 20 years old now and it shows. I have read both books and it is remarkable how much more we learned in the time between them. [0]: https://www.amazon.com/Why-We-Sleep-Unlocking-Dreams/dp/1501144316 https://www.amazon.com/Why-We-Sleep-Unlocking-Dreams/dp/1501...
dsnuh 8y ago
Do we know which animals experience the most R.E.M. sleep, or if humans display atypical R.E.M. sleep characteristics compared to other animals?
- Felz 8y ago
  Not a direct answer, but immediate REM sleep is a symptom of narcolepsy. So the animal displaying the most REM sleep is probably a narcoleptic human. It just makes you tired, no matter how much sleep you get.
rayiner 8y ago
> n fact, the earlier studies on R.E.M. deprivation might not have been as compelling as they once seemed. > In those earlier studies, researchers kept animals from going into R.E.M. sleep by waking them up. “In some experiments, they wake up the animals a thousand times a day,” Dr. Siegel said. So much science that I used to take for granted is garbage.
- pulse7 8y ago
  I many cases, the science is not talking about real proofs (in the mathematical sense) but marely about assumptions based on some (or many) indicators. Such "science" should not be part of the real science. The real sciense should contain ONLY the things which are proved with real proofs!
  - vertexFarm 8y ago
    If that were true we'd be paralyzed by solipsism and skepticism. Sometimes you have to make do with a working hypothesis. You can't eat mathematical proofs.
    - IncRnd 8y ago
      But that's the essential point, that what you call working hypothesis are actually untested hypothesis. Using an untested hypothesis as a working hypothesis is bad science that may actually be counterproductive, unbeknownst to the users of the working hypothesis.
      - smallnamespace 8y ago
        You always depend on an untested hypotheses at some point. They are absolutely unavoidable. Here's a very simple example: - How much testing is sufficient? For example, as far as we can tell the laws of physics don't vary over time scales that we can directly observe. This has been true as far as we can tell. - So far so good: the hypothesis that 'the laws of physics don't change' has been 'tested'. Next question: is that amount of testing sufficient? - Well, that seems to be an untestable proposition; it's always philosophically possible that things get pulled out from under your feet, and no amount of testing up to time T lets you know with complete certainty what happens for t > T. Go even one or two steps deeper, and you quickly find yourself resting on either unfounded, untested, or untestable assumptions.
yosito 8y ago
So the hypothesis is that mammals need REM sleep to prevent the brain from getting too cold while sleeping, but the hypothesis hasn't been tested yet. If this turns out to be true, I wonder if it has implications for night terrors. It seems plausible that if the brain fails to warm enough through REM sleep, hormones are released to wake the brain up completely which lead to night terrors and the adrenaline rush feeling that accompanies them. These are just hypotheses, but interesting nonetheless.
- djsumdog 8y ago
  There was also some research a while back where scientists theorized that sleep is also used to clean out the brain: https://www.nih.gov/news-events/nih-research-matters/how-sleep-clears-brain https://www.nih.gov/news-events/nih-research-matters/how-sle... It could mean that constant sleep deprivation could increase the risk of Alzheimer's, but of course that's really difficult to test since you'd need a lifetime of sleep data for humans in their 60s/70s. Also I think that paper was just about sleep in general, not specifically dreams/REM sleep.
  - eloff 8y ago
    I read an article long ago (I searched now but didn't find it) where a family had a rare genetic disorder that prevents sleep and gets worse with time. The afflicted family members essentially go into an early dementia in their fourties or early fifties that's fatal. I don't know how similar that is to Alzheimer's, but it seems to lend weight to the theory that lack of sleep could be a contributing cause of dementia.
    - jarvist 8y ago
      It's a pretty harrowing story. http://www.bbc.com/future/story/20160118-the-tragic-fate-of-the-people-who-stop-sleeping http://www.bbc.com/future/story/20160118-the-tragic-fate-of-...
      - eloff 8y ago
deleted 8y ago
[deleted]
albertgoeswoof 8y ago
Another clickbait title, it should really be “an unproven theory for why mammals need R.E.M. sleep based on seals” Or even “R.E.M. sleep might be a trait evolved to keep your brain warm at night”
weliketocode 8y ago
I know a very successful banker who prides himself on sleeping 4 hours a night because he believes that is the optimal point where each additional hour no longer has any incremental benefit. I have gone through periods of high and low amounts of sleep for both work and personal reasons. Sleep has always been phrased in terms of time - ie get x hours of uninterrupted sleep to perform your best. But there has to be more to it than that. I've stayed up all night and felt rejuvenated the next day. And I've had lazy Sundays where I've remained tired the entire day. I might not have not seen the scientific study on it yet, but I believe the quality of your sleep has a lot to do with the nature of when and why you're sleeping as well as your mental state when doing so.
- djsumdog 8y ago
  There are some humans who only need 5 hours of sleep a night. Others that need 8 or 10. A good indicator is during a long vacation, without an alarm, how long do you typically sleep? If I allow my body to wake up naturally, it's almost always after 7 hours. If you go long enough without needing to be on a schedule, studies have found a lot of people move back into a rolling/rotating sleep cycle .. a few hours at a time throughout the day/night. I found myself doing this while I took a several month sabbatical from the workforce.
  - acct1771 8y ago
    > There are some humans who only need 5 hours of sleep Define "need". Also, citation needed. Just because you can get away with it and live, doesn't mean it's the best move.
    - JumpCrisscross 8y ago
      > citation needed “In 2009, a woman came into Ying-Hui Fu’s lab at the University of California, San Francisco, complaining that she always woke up too early. At first, Fu thought the woman was an extreme morning lark – a person who goes to bed early and wakes early. However, the woman explained that she actually went to bed around midnight and woke at 4am feeling completely alert. It was the same for several members of her family, she said. Fu and her colleagues compared the genome of different family members. They discovered a tiny mutation in a gene called DEC2 that was present in those who were short-sleepers, but not in members of the family who had normal length sleep, nor in 250 unrelated volunteers. When the team bred mice to express this same mutation, the rodents also slept less but performed just as well as regular mice when given physical and cognitive tasks.“ http://www.bbc.com/future/story/20150706-the-woman-who-barely-sleeps http://www.bbc.com/future/story/20150706-the-woman-who-barel...
daxfohl 8y ago
If it's related to warmth, then why would rats have to make it up after days of deprivation? Overheating seems like it would be just as destructive.
startupdiscuss 8y ago
You know my performance might change imperceptibly with sleep, but the area where I know it makes a difference -- probably the most important area -- is how nice I am to fellow human beings. I am a better co-worker, family member, client etc with sleep. They should look at aggression in animals rather than how well they do tasks.
John_KZ 8y ago
To me this looks like evidence that seals don't enjoy sleeping in water very much. Not much else. Also sleep-deprived rats seem to consume more calories. Wow.
prats226 8y ago
Is it just heating of brain required or blood flow? One crazy way to test would be to artificially heat the brain!
jrmg 8y ago
Have there been studies of sleep need, or sleep quality, vs temperature? I wonder if the modern (American?) trend of running heating at night is affecting people's sleep? As a Briton who moved to the USA a few years ago, I found the American habit of running heating overnight to be very odd - as I think most Europeans do. In Britain, we tend to run heating only during the day, unless it's extremely cold outside.
_emacsomancer_ 8y ago
I thought the received wisdom was that REM sleep was connected to memory. E.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/
_bxg1 8y ago
I've always found that I get exceedingly warm when I sleep. Whenever I fall asleep on a bus or plane, I eventually wake up drenched in sweat. It's not from bad dreams or night-terrors; my body temperature just increases. I now wonder if it's specific to REM.
- manmal 8y ago
  Night sweats can also hint at a chronic infection or hypoglycemia. Can you exclude those?
- Jeff_Brown 8y ago
  Every night I have to throw a few blankets off of me in the early morning. I read somewhere (?) that the body cools during sleep. Somehow one of the implications was that taking a shower before sleep can help you sleep faster. The fact that a body is sweating indicates not necessarily that it is hotter than during the day; it could be that the body is trying to be cooler than it was during the day. (Of course, if you wake up feeling hot, it's probably because you're hot.) Thermodynamically, it makes sense that being in a bed, with insulation against almost all of one's body, would (once the insulation gets warm) leave someone warmer than when they're sitting or standing -- at least if the ambient temperature is the same in the day and night.
ndh2 8y ago
What is the connection between swimming and heat? How did they even arrive at this hypothesis? Why would rats need to catch up on heating their brains, days after missing REM sleep? The facts are interesting, the conclusion doesn't make any sense at all to me.
- strict9 8y ago
  It's weird to me too. But articles says it's because the brain alternates activity in hemispheres. It switches activity to each hemisphere, possibly as it gets too cool. >These marine mammals have evolved a half-brain style of sleeping, perhaps as a way to remain alert enough to avoid predators and drowning. >Because part of the brain is always active, it’s always warm. As a result, it never triggers R.E.M. sleep.
  - John_KZ 8y ago
    It's weird they don't mention the much more obvious fact that an air-breathing mammal might need to maintain some level of alertness when sleeping in water.
    - djmips 8y ago
      From the article: "These marine mammals have evolved a half-brain style of sleeping, perhaps as a way to remain alert enough to avoid predators and drowning."
- cpncrunch 8y ago
  Regarding the rats: the study has an explanation for that too. It says the rats were woken up thousands of times a day, and they are catching up on the lack of sleep rather than lack of REM.
  - djmips 8y ago
    The article says they have more REM after they miss out on it. The ratio is not the same as normal sleep.
pdkl95 8y ago
REM cannot be strictly necessary because I don't get any REM sleep (or so little it's difficult to detect) due to severe sleep apnea (AHI=148). Three different sleep studies (using two unrelated labs+doctors) produced very similar results. The hypnogram was always a narrow rectangle of rapid oscillations (λ ~= 25-35 seconds) between NREM stages 1 and 2. Obviously this has caused harm, but it's difficult to isolate how much of that harm (if any) is caused by lack of REM when the dips in oxygen saturation could easily be the causing most of the problems.
Tycho 8y ago
My personal theory was that dreaming allows humans to rest while staying somewhat alert to the environment (because outside phenomena tend to manifest inside dreams). The phased aspect of REM sleep allow groups of humans to sleep at night while guaranteeing that some members of the group will be in REM rather than deep sleep at any given time, so the group never becomes completely unconscious of the surrounding environment.
- bleke 8y ago
  My couch scientist theory is that REM sleep is phase when brains reconnects and tunes quantum links between neuron groups (assuming brain is big quantum computer underneath), that why there are chaotic movements.
  - hexane360 8y ago
    That's a pretty big assumption there. There's a huge difference between "exploits a quantum effects" (like classical computers today) and "is a quantum computer". What evidence leads you to suspect the latter?
- geuis 8y ago
  Hypothesis, not theory.
  - yesenadam 8y ago
    Yes, but....the usage you apparently objected to is how the word theory is used in the world, i.e. it's one of the meanings of the word. At least, I looked in a couple of dictionaries and they gave sentences just like the one you objected to, as examples of correct usage. Yes, in science, the word has a narrower meaning; I'm sure people on here know that.
- taneq 8y ago
  My guess was that dreaming is just cross-talk while our brain consolidates and archives our memories from the day, and uses them to train for the next day.
textor 8y ago
Just so you know, there's half a dozen of equally plausible hypotheses about REM function, and dozens more of more fantastical. Most amusing one yet is about synthesis of molecular chaperones that guard against aggregation of chains produced during NREM. But honestly we just don't know. Personally I agree with Marcus Schmidt and his idea of "energy allocation function of sleep". Basically it says that distinct physiological states provide viable configurations of priorities for vital functions that allow for the lowest possible energy expenditure over the whole cycle. I.e. there's no single specific function of REM sleep, it hosts all functions that are too costly to prioritize during other states, and the same is true for NREM.
- iagooar 8y ago
  That means that biology uses the same idea of having "background jobs" and worker queues that get more relevant while the main function has a bit less to do: many IT systems will schedule some tasks during the night when there is not much going on, so they can prioritize them because otherwise they wouldn't get a chance during the day. I wonder if there are universal laws that transcend biology and technology, all following the same rules that we haven't figured out yet.
  - pm90 8y ago
    Everything derives from the laws of physics (well as we understand it now at least; our understanding has and will change in the future) so its not that surprising that in aggregate they would result in similar systems. I'm not saying its not fascinating though. It is incredibly fascinating, and this kind of research is exactly why we should be investing MORE not less in pure science.
    - nonbel 8y ago
      >"this kind of research is exactly why we should be investing MORE not less in pure science." I disagree. Look at the paper: https://www.cell.com/current-biology/fulltext/S0960-9822(18)30624-9 https://www.cell.com/current-biology/fulltext/S0960-9822(18)... Can you point out where they even report the temperature of the brain/brainstem? This looks like it is just wild speculation.
randyrand 8y ago
My personal theory is that REM has many uses - one of which is giving the brain an opportunity to do reinforcement learning.
dghughes 8y ago
If you found that interesting you should read about why our bodies are at the temperature they are, 37C. The tl;dr is to fight off fungus.
tw1010 8y ago
I feel weird about this post. It feels like it's posted by people wanting to somehow give evidence or support to the idea that sleep is good and necessary. I feel weird about the fact that that is something that needs to be proved. Don't you trust in the signals your body is sending you? Do you really trust a model of average human behaviour more than your body; which is perfectly conditioned your precise enviourment and history?
pvaldes 8y ago
I would be cautious about extrapolating seal metabolism to mammal metabolism. Diving mammals have many special adaptations to deal with high pressure, breathing, oxygen, nitrogen etc. Is an interesting history in any case.
ConcernedCoder 8y ago
I think it's got more to do with maintenance, not temperature. From my own experience, lack of sleep leads quickly to "spinning my wheels" as my thought process becomes bogged down to the point of not being able to "finish a thought". At some point the brain needs to clean out molecular by-products, replenish stores of needed neurotransmitters, I'm sure at some level there's some garbage collection going on, maybe mark and sweep everything out of short term memory that's been moved to long term. Maybe dreaming actively helps us to connect disparate thoughts and concepts into some kind of of aggregate. Some of my best thinking comes easily after a great nights sleep...
candiodari 8y ago
If this is true, then why are there such extreme consequences to not sleeping for extended periods in mammals ? Without REM sleep (deep sleep does not work by itself), you lose control of your emotions in 2 days at most. You go insane between 1 and 2 weeks (mania, depression, and likely quick switches between those 2), and your body will physically shut down and die a week or so after that. (note that in humans it hasn't been well established that death occurs, for obvious reasons. In mice, however, it's well studied and accepted. No sleep for ~10 days, half of the mice just die). This seems to be a bit at odds with the idea that it's just a brain warming technique. https://www.healthline.com/health/sleep-deprivation/effects-on-body#1 https://www.healthline.com/health/sleep-deprivation/effects-... https://www.livescience.com/52592-spooky-effects-sleep-deprivation.html https://www.livescience.com/52592-spooky-effects-sleep-depri...

291 points by dnetesn 8y ago

Natural question follows: can humans train ourselves to do the same as animals in water? Live a bi-phasic life where creative / analytical sides of brain each get to "sleep"?

newnewpdro 8y ago
Humans are animals
- ivanhoe 8y ago
  Sure, but we're not "animals in water" as OP wrote? Perhaps reading the full sentence before commenting? Just an idea...
  - newnewpdro 8y ago
    I read the entire sentence, but had not yet read the article, and had not had my morning coffee yet. After looking through the article, given the context it's pretty obvious they were probably referring to Amphibians. The sentence is poorly worded, because when a human is in water, it's an animal in water. Through that lens alone it makes no sense.
SimonPStevens 8y ago
The character Kraiklyn in the Iain M Banks novel Consider Phlebas has had enhancements to his brain to be able to do this.
alfredallan1 8y ago
It is not the same thing, but some people learn to switch between analytical and creative activity. I am many more could, if they tried hard enough.. Of course, there’s no recipe for how to learn this sort of thing which makes it a lot harder.
- creep 8y ago
  True. I go through phases like this. For two whole weeks I will write (creatively) and draw, and then I usually find there is a day or two when I can't seem to do much of anything useful besides menial tasks and watching stupid videos. Then I go through another two weeks of analytical stuff-- reading, catching up on work (programming and mathy stuff), and doing planning for my writing. I can control it, if necessary in a day. The urge to do one thing or another is an intense "mood" for me (which, like I said, normally has a two-week period). This indicates some kind of synchronization, so if I want to switch I use musical triggers: airy, melodic music for creativity, and beat-heavy, algorithmic music for analytical activity. I only need to listen to the music for a few minutes to switch, and of course it sometimes doesn't work but I don't know of any other triggers. Possibly going out for a short walk could do it too? Meditation?
gus_massa 8y ago
Probably nobody knows, but I guess these animals have an special adaptation to make bi-phasic sleep possible. I guess that to evolve it you only need to keeping an isolated human population for a few million years were you kill at random some of the one that are sleeping, to encourage swallow sleeping and later bi-phasic sleep. Another possibility is trying a genetic modification, but it's impossible with the current technology and knowledge, perhaps in the future ... If you want to have a peek, you can read about the Wada Test https://en.wikipedia.org/wiki/Wada_test https://en.wikipedia.org/wiki/Wada_test . (And somehow related https://en.wikipedia.org/wiki/Split-brain https://en.wikipedia.org/wiki/Split-brain )
vertexFarm 8y ago
The creative / analytical dichotomy of the brain is a myth I'm afraid.
djsumdog 8y ago
It would depend on how this evolved in the water mammals researchers have found this in. Maybe some land mammals do the same thing, we just have preformed this type of experiment on them yet. If it does appear in humans, it'd probably be best to study those with extreme insomnia or people who claim to have very short sleep patterns (<2 hours a night) or maybe those who are narcoleptic (the other end of that scale).
- darkerside 8y ago
  So we need a volunteer to put the electrodes on the hippopotamus?

Smaug123 8y ago

My first reaction was that it seems so inefficient to bring the entire computer online just to maintain its temperature - which could be controlled physically using blood. But couldn't we test this by artificially keeping the brain warm and seeing what sleep patterns emerge?

creep 8y ago
As an anecdote, I always have intense dreams with fever. I'm prone to kidney infections so I experience this often. My head is clearly very warm, my brain swells a little with the heat, and my dreams are clear and intense.
- spydum 8y ago
  this would seem likely because you aren't sleeping well or deeply, hence able to recall the dreams.
  - creep 8y ago
    I usually recall my dreams, fever or not. There is a marked difference between them.
stepik777 8y ago
> it seems so inefficient to bring the entire computer online just to maintain its temperature In what sense is it inefficient? In terms of energy 100% is converted to heat anyway
- manmal 8y ago
  Some of that should be converted into lowering entropy (building neural structures etc) so I don’t think 100% escapes as heat.
iforgotpassword 8y ago
thats what i thought. seems easy enough to do. I'd like to see more evidence to support that theory, I'm rather sceptical. i was remembered of that very rare condition where your brain cannot ever enter the deeper sleep states. these people usually die rather soon after onset of exhaustion. what has been confirmed through these people is that narcotics dont help at all. while you can ise it to make them 'sleep' long enough, it's not helping with the condition. so brain warming cannot be the main reason for REM, if it's one at all. edit: fatal insomnia is what i was referring to.

maxander 8y ago

You expect a future where brain implants will be tiny computers that make you smarter, but perhaps instead you get a future where brain implants are tiny heating coils that make you wake up earlier.

manmal 8y ago
I‘m pretty sure I won’t have any kind of brain device installed, no matter the upsides. No upgrades for that hardware!
- Jeff_Brown 8y ago
  I feel the opposite. As soon as it's possible to replace biological neurons with artificial one, even if they aren't perfect replicas, I'm in. I'm pretty sure the mind is an emergent phenomenon robust to slight variations in the lowest levels of hardware, and I'd like to live for billions of years. (And if the tech lets you process faster, it could feel like trillions.)

dpods 8y ago

I'd recommend the book "The Promise of Sleep" [0] for anyone that's interested in learning more about sleep. The author basically pioneered the sleep medicine field and was at the University of Chicago in 1951 when R.E.M. sleep was discovered. [0]: https://www.amazon.com/Promise-Sleep-Medicine-Connection-Happiness/dp/0440509017 https://www.amazon.com/Promise-Sleep-Medicine-Connection-Hap...

toomuchtodo 8y ago
Thanks, purchased! Sidenote: The book recommendations on HN are always top notch.
Styrke 8y ago
I would recommend reading Why We Sleep by Matthew Walker instead. [0] The Promise of Sleep is an okay book, but it is almost 20 years old now and it shows. I have read both books and it is remarkable how much more we learned in the time between them. [0]: https://www.amazon.com/Why-We-Sleep-Unlocking-Dreams/dp/1501144316 https://www.amazon.com/Why-We-Sleep-Unlocking-Dreams/dp/1501...

dsnuh 8y ago

Do we know which animals experience the most R.E.M. sleep, or if humans display atypical R.E.M. sleep characteristics compared to other animals?

Felz 8y ago
Not a direct answer, but immediate REM sleep is a symptom of narcolepsy. So the animal displaying the most REM sleep is probably a narcoleptic human. It just makes you tired, no matter how much sleep you get.

rayiner 8y ago

> n fact, the earlier studies on R.E.M. deprivation might not have been as compelling as they once seemed. > In those earlier studies, researchers kept animals from going into R.E.M. sleep by waking them up. “In some experiments, they wake up the animals a thousand times a day,” Dr. Siegel said. So much science that I used to take for granted is garbage.

pulse7 8y ago
I many cases, the science is not talking about real proofs (in the mathematical sense) but marely about assumptions based on some (or many) indicators. Such "science" should not be part of the real science. The real sciense should contain ONLY the things which are proved with real proofs!
- vertexFarm 8y ago
  If that were true we'd be paralyzed by solipsism and skepticism. Sometimes you have to make do with a working hypothesis. You can't eat mathematical proofs.
  - IncRnd 8y ago
    But that's the essential point, that what you call working hypothesis are actually untested hypothesis. Using an untested hypothesis as a working hypothesis is bad science that may actually be counterproductive, unbeknownst to the users of the working hypothesis.
    - smallnamespace 8y ago
      You always depend on an untested hypotheses at some point. They are absolutely unavoidable. Here's a very simple example: - How much testing is sufficient? For example, as far as we can tell the laws of physics don't vary over time scales that we can directly observe. This has been true as far as we can tell. - So far so good: the hypothesis that 'the laws of physics don't change' has been 'tested'. Next question: is that amount of testing sufficient? - Well, that seems to be an untestable proposition; it's always philosophically possible that things get pulled out from under your feet, and no amount of testing up to time T lets you know with complete certainty what happens for t > T. Go even one or two steps deeper, and you quickly find yourself resting on either unfounded, untested, or untestable assumptions.

yosito 8y ago

So the hypothesis is that mammals need REM sleep to prevent the brain from getting too cold while sleeping, but the hypothesis hasn't been tested yet. If this turns out to be true, I wonder if it has implications for night terrors. It seems plausible that if the brain fails to warm enough through REM sleep, hormones are released to wake the brain up completely which lead to night terrors and the adrenaline rush feeling that accompanies them. These are just hypotheses, but interesting nonetheless.

djsumdog 8y ago
There was also some research a while back where scientists theorized that sleep is also used to clean out the brain: https://www.nih.gov/news-events/nih-research-matters/how-sleep-clears-brain https://www.nih.gov/news-events/nih-research-matters/how-sle... It could mean that constant sleep deprivation could increase the risk of Alzheimer's, but of course that's really difficult to test since you'd need a lifetime of sleep data for humans in their 60s/70s. Also I think that paper was just about sleep in general, not specifically dreams/REM sleep.
- eloff 8y ago
  I read an article long ago (I searched now but didn't find it) where a family had a rare genetic disorder that prevents sleep and gets worse with time. The afflicted family members essentially go into an early dementia in their fourties or early fifties that's fatal. I don't know how similar that is to Alzheimer's, but it seems to lend weight to the theory that lack of sleep could be a contributing cause of dementia.
  - jarvist 8y ago
    It's a pretty harrowing story. http://www.bbc.com/future/story/20160118-the-tragic-fate-of-the-people-who-stop-sleeping http://www.bbc.com/future/story/20160118-the-tragic-fate-of-...
    - eloff 8y ago

deleted 8y ago

[deleted]

albertgoeswoof 8y ago

Another clickbait title, it should really be “an unproven theory for why mammals need R.E.M. sleep based on seals” Or even “R.E.M. sleep might be a trait evolved to keep your brain warm at night”

weliketocode 8y ago

I know a very successful banker who prides himself on sleeping 4 hours a night because he believes that is the optimal point where each additional hour no longer has any incremental benefit. I have gone through periods of high and low amounts of sleep for both work and personal reasons. Sleep has always been phrased in terms of time - ie get x hours of uninterrupted sleep to perform your best. But there has to be more to it than that. I've stayed up all night and felt rejuvenated the next day. And I've had lazy Sundays where I've remained tired the entire day. I might not have not seen the scientific study on it yet, but I believe the quality of your sleep has a lot to do with the nature of when and why you're sleeping as well as your mental state when doing so.

djsumdog 8y ago
There are some humans who only need 5 hours of sleep a night. Others that need 8 or 10. A good indicator is during a long vacation, without an alarm, how long do you typically sleep? If I allow my body to wake up naturally, it's almost always after 7 hours. If you go long enough without needing to be on a schedule, studies have found a lot of people move back into a rolling/rotating sleep cycle .. a few hours at a time throughout the day/night. I found myself doing this while I took a several month sabbatical from the workforce.
- acct1771 8y ago
  > There are some humans who only need 5 hours of sleep Define "need". Also, citation needed. Just because you can get away with it and live, doesn't mean it's the best move.
  - JumpCrisscross 8y ago
    > citation needed “In 2009, a woman came into Ying-Hui Fu’s lab at the University of California, San Francisco, complaining that she always woke up too early. At first, Fu thought the woman was an extreme morning lark – a person who goes to bed early and wakes early. However, the woman explained that she actually went to bed around midnight and woke at 4am feeling completely alert. It was the same for several members of her family, she said. Fu and her colleagues compared the genome of different family members. They discovered a tiny mutation in a gene called DEC2 that was present in those who were short-sleepers, but not in members of the family who had normal length sleep, nor in 250 unrelated volunteers. When the team bred mice to express this same mutation, the rodents also slept less but performed just as well as regular mice when given physical and cognitive tasks.“ http://www.bbc.com/future/story/20150706-the-woman-who-barely-sleeps http://www.bbc.com/future/story/20150706-the-woman-who-barel...

daxfohl 8y ago

If it's related to warmth, then why would rats have to make it up after days of deprivation? Overheating seems like it would be just as destructive.

startupdiscuss 8y ago

You know my performance might change imperceptibly with sleep, but the area where I know it makes a difference -- probably the most important area -- is how nice I am to fellow human beings. I am a better co-worker, family member, client etc with sleep. They should look at aggression in animals rather than how well they do tasks.

John_KZ 8y ago

To me this looks like evidence that seals don't enjoy sleeping in water very much. Not much else. Also sleep-deprived rats seem to consume more calories. Wow.

prats226 8y ago

Is it just heating of brain required or blood flow? One crazy way to test would be to artificially heat the brain!

jrmg 8y ago

Have there been studies of sleep need, or sleep quality, vs temperature? I wonder if the modern (American?) trend of running heating at night is affecting people's sleep? As a Briton who moved to the USA a few years ago, I found the American habit of running heating overnight to be very odd - as I think most Europeans do. In Britain, we tend to run heating only during the day, unless it's extremely cold outside.

_emacsomancer_ 8y ago

I thought the received wisdom was that REM sleep was connected to memory. E.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/

_bxg1 8y ago

I've always found that I get exceedingly warm when I sleep. Whenever I fall asleep on a bus or plane, I eventually wake up drenched in sweat. It's not from bad dreams or night-terrors; my body temperature just increases. I now wonder if it's specific to REM.

manmal 8y ago
Night sweats can also hint at a chronic infection or hypoglycemia. Can you exclude those?
Jeff_Brown 8y ago
Every night I have to throw a few blankets off of me in the early morning. I read somewhere (?) that the body cools during sleep. Somehow one of the implications was that taking a shower before sleep can help you sleep faster. The fact that a body is sweating indicates not necessarily that it is hotter than during the day; it could be that the body is trying to be cooler than it was during the day. (Of course, if you wake up feeling hot, it's probably because you're hot.) Thermodynamically, it makes sense that being in a bed, with insulation against almost all of one's body, would (once the insulation gets warm) leave someone warmer than when they're sitting or standing -- at least if the ambient temperature is the same in the day and night.

ndh2 8y ago

What is the connection between swimming and heat? How did they even arrive at this hypothesis? Why would rats need to catch up on heating their brains, days after missing REM sleep? The facts are interesting, the conclusion doesn't make any sense at all to me.

strict9 8y ago
It's weird to me too. But articles says it's because the brain alternates activity in hemispheres. It switches activity to each hemisphere, possibly as it gets too cool. >These marine mammals have evolved a half-brain style of sleeping, perhaps as a way to remain alert enough to avoid predators and drowning. >Because part of the brain is always active, it’s always warm. As a result, it never triggers R.E.M. sleep.
- John_KZ 8y ago
  It's weird they don't mention the much more obvious fact that an air-breathing mammal might need to maintain some level of alertness when sleeping in water.
  - djmips 8y ago
    From the article: "These marine mammals have evolved a half-brain style of sleeping, perhaps as a way to remain alert enough to avoid predators and drowning."
cpncrunch 8y ago
Regarding the rats: the study has an explanation for that too. It says the rats were woken up thousands of times a day, and they are catching up on the lack of sleep rather than lack of REM.
- djmips 8y ago
  The article says they have more REM after they miss out on it. The ratio is not the same as normal sleep.

pdkl95 8y ago

REM cannot be strictly necessary because I don't get any REM sleep (or so little it's difficult to detect) due to severe sleep apnea (AHI=148). Three different sleep studies (using two unrelated labs+doctors) produced very similar results. The hypnogram was always a narrow rectangle of rapid oscillations (λ ~= 25-35 seconds) between NREM stages 1 and 2. Obviously this has caused harm, but it's difficult to isolate how much of that harm (if any) is caused by lack of REM when the dips in oxygen saturation could easily be the causing most of the problems.

Tycho 8y ago

My personal theory was that dreaming allows humans to rest while staying somewhat alert to the environment (because outside phenomena tend to manifest inside dreams). The phased aspect of REM sleep allow groups of humans to sleep at night while guaranteeing that some members of the group will be in REM rather than deep sleep at any given time, so the group never becomes completely unconscious of the surrounding environment.

bleke 8y ago
My couch scientist theory is that REM sleep is phase when brains reconnects and tunes quantum links between neuron groups (assuming brain is big quantum computer underneath), that why there are chaotic movements.
- hexane360 8y ago
  That's a pretty big assumption there. There's a huge difference between "exploits a quantum effects" (like classical computers today) and "is a quantum computer". What evidence leads you to suspect the latter?
geuis 8y ago
Hypothesis, not theory.
- yesenadam 8y ago
  Yes, but....the usage you apparently objected to is how the word theory is used in the world, i.e. it's one of the meanings of the word. At least, I looked in a couple of dictionaries and they gave sentences just like the one you objected to, as examples of correct usage. Yes, in science, the word has a narrower meaning; I'm sure people on here know that.
taneq 8y ago
My guess was that dreaming is just cross-talk while our brain consolidates and archives our memories from the day, and uses them to train for the next day.

textor 8y ago

Just so you know, there's half a dozen of equally plausible hypotheses about REM function, and dozens more of more fantastical. Most amusing one yet is about synthesis of molecular chaperones that guard against aggregation of chains produced during NREM. But honestly we just don't know. Personally I agree with Marcus Schmidt and his idea of "energy allocation function of sleep". Basically it says that distinct physiological states provide viable configurations of priorities for vital functions that allow for the lowest possible energy expenditure over the whole cycle. I.e. there's no single specific function of REM sleep, it hosts all functions that are too costly to prioritize during other states, and the same is true for NREM.

iagooar 8y ago
That means that biology uses the same idea of having "background jobs" and worker queues that get more relevant while the main function has a bit less to do: many IT systems will schedule some tasks during the night when there is not much going on, so they can prioritize them because otherwise they wouldn't get a chance during the day. I wonder if there are universal laws that transcend biology and technology, all following the same rules that we haven't figured out yet.
- pm90 8y ago
  Everything derives from the laws of physics (well as we understand it now at least; our understanding has and will change in the future) so its not that surprising that in aggregate they would result in similar systems. I'm not saying its not fascinating though. It is incredibly fascinating, and this kind of research is exactly why we should be investing MORE not less in pure science.
  - nonbel 8y ago
    >"this kind of research is exactly why we should be investing MORE not less in pure science." I disagree. Look at the paper: https://www.cell.com/current-biology/fulltext/S0960-9822(18)30624-9 https://www.cell.com/current-biology/fulltext/S0960-9822(18)... Can you point out where they even report the temperature of the brain/brainstem? This looks like it is just wild speculation.

randyrand 8y ago

My personal theory is that REM has many uses - one of which is giving the brain an opportunity to do reinforcement learning.

dghughes 8y ago

If you found that interesting you should read about why our bodies are at the temperature they are, 37C. The tl;dr is to fight off fungus.

tw1010 8y ago

I feel weird about this post. It feels like it's posted by people wanting to somehow give evidence or support to the idea that sleep is good and necessary. I feel weird about the fact that that is something that needs to be proved. Don't you trust in the signals your body is sending you? Do you really trust a model of average human behaviour more than your body; which is perfectly conditioned your precise enviourment and history?

pvaldes 8y ago

I would be cautious about extrapolating seal metabolism to mammal metabolism. Diving mammals have many special adaptations to deal with high pressure, breathing, oxygen, nitrogen etc. Is an interesting history in any case.

ConcernedCoder 8y ago

I think it's got more to do with maintenance, not temperature. From my own experience, lack of sleep leads quickly to "spinning my wheels" as my thought process becomes bogged down to the point of not being able to "finish a thought". At some point the brain needs to clean out molecular by-products, replenish stores of needed neurotransmitters, I'm sure at some level there's some garbage collection going on, maybe mark and sweep everything out of short term memory that's been moved to long term. Maybe dreaming actively helps us to connect disparate thoughts and concepts into some kind of of aggregate. Some of my best thinking comes easily after a great nights sleep...

candiodari 8y ago

If this is true, then why are there such extreme consequences to not sleeping for extended periods in mammals ? Without REM sleep (deep sleep does not work by itself), you lose control of your emotions in 2 days at most. You go insane between 1 and 2 weeks (mania, depression, and likely quick switches between those 2), and your body will physically shut down and die a week or so after that. (note that in humans it hasn't been well established that death occurs, for obvious reasons. In mice, however, it's well studied and accepted. No sleep for ~10 days, half of the mice just die). This seems to be a bit at odds with the idea that it's just a brain warming technique. https://www.healthline.com/health/sleep-deprivation/effects-on-body#1 https://www.healthline.com/health/sleep-deprivation/effects-... https://www.livescience.com/52592-spooky-effects-sleep-deprivation.html https://www.livescience.com/52592-spooky-effects-sleep-depri...