26 ms·

Brains Sweep Themselves Clean of Toxins During Sleep (2013)

420 points by phatboyslim 9y ago

rl3 9y ago
Title should be updated to reflect 2013.
- djsumdog 9y ago
  Yes, I remember seeing this on here several months ago. Still good for all the people who may have missed it.
mabbo 9y ago
> The process is important because what's getting washed away during sleep are waste proteins that are toxic to brain cells, Nedergaard says. Evolution found a nice little optimum in sleep that works pretty well- use less energy during a time of the day that isn't a very efficient time to be awake while also cleaning out the brain. This could be interesting for future research. Could we find chemical means to remove those waste proteins?
- bryondowd 9y ago
  There's an interesting concept. I wonder what the trade-off would be. How much efficiency would it cost to clean the brain continually rather than in a dedicated sleep cycle? Would it even be possible to process these toxins while maintaining consciousness? I'm sure there could be huge benefits for many modern lifestyles to trade heavily on reaction speed and/or lightly on IQ for 50% more waking hours. Or even 25% more waking hours, if you just cut the need for sleep in half, over the long term.
  - mrzool 9y ago
    Why force things? I don't want 50% more waking hours. I enjoy my sleep tremendously.
    - bmelton 9y ago
      I suspect (but do not know) that you enjoy your sleep because of its restorative effect. If you could obviate the need for the restorative effect, and instead just always feel newly restored, would you still enjoy going to sleep for no reason? Personally, I dislike the need for sleep. I put it off for as long as I can manage, and try to get as little of it as I can get away with. For me, I have a hard time functioning well with less than 4 hours a night, but anything more then 5.5 hours and I feel like I've thrown the day away. The idea of voluntarily checking out from the world isn't as relaxing to me as picking up a book to read, or learning something new, or doing something productive that isn't work/startup-related. Either way, I assume that nobody would force you to take a drug that you didn't want to take.
      - eckza 9y ago
        Oh my god, think of what this would do to commerce, in terms of a capitalist society. Suddenly, you can take a drug that decreases your need for sleep by 50%. People only need 4h of sleep per night now, for a full nights' sleep - 3h, if you're willing to skimp a little, 2h isn't unheard of (in the way that only getting 4h of sleep a night, now, isn't unheard of either). Suddenly, there's a significant advantage in the hands of everyone willing to take this drug. Students are expected to study more and harder, because they don't need 8h of sleep every night. Entrance exams to schools get more difficult. Software developers are now enticed to work longer hours - longer hours than they already are. Labor / shift workers (hospitality / food industry) are expected to work longer shifts, and they have to, because businesses have to be open longer because more people are awake for more of the day. Now, also, you have to consider: this is just sleep, in terms of brain repair. Your body has to put itself back together every night, too - repairing microscopic muscle tears, fixing bruises, etc etc etc. Your body would probably start slowly falling apart on 2-3h of sleep per night, even if your mind was fully rested. I really, really hope this doesn't happen.
        ChuckMcM 9y ago
        It is entirely possible that it would evolve differently, perhaps given that not everyone would be available during the 'dark' hours you might see a society evolve into dual function, where 8 hours were for 'working' and 8 hours were for 'community/family' with 8 hours split into two 4 hour segments as 'transition times'.
  - clort 9y ago
    some birds (and dolphins?) sleep one hemisphere at a time, so that they can keep flying
  - JoshCole 9y ago
    I think from the evolutionary perspective, being active during a time of low fitness gets punished. So if there was an adaption that tended to paralyze something when it was dark out, that gets selected for even though obviously given optimal decisions not being paralyzed is better. Which, if you think about it, is kind of what is happening with sleep. So I imagine the trade-off isn't as severe as someone might guess; it's definitely theoretically possible to run entirely without sleep with the right hardware. For example, lets say sleep was fundamental to cognition. If you were willing to have redundant hardware, you could run two brains and just take turns sleeping them [1]. So that probably gives something of an upper-bound to efficiency. The problem is that a lot of stuff is getting built on top of these things. Scheduled downtime is getting used by other adaptions. Things like handling 'garbage collection' or 'waste collection' inline get shunted away to the downtime to improve response times. This keeps happening. Over short periods there are going to be plenty of cases where being paralyzed isn't optimal. What if something shows in the night? Long term though if the creature is continually staying active when its at disadvantage that's really bad. So additional penalties accrue to force the issue. Then the original 'purpose/benefit' starts getting lost. Things get messed up. Enough adaptions end up taking advantage of the fact that the downtime existed that now there is so much benefit to it for reasons unrelated to its initial creation that it starts becoming worth doing even at times where light levels aren't an issue. So now when you try to mess with sleep, you're not just messing with one little thing. You're messing with a whole bunch of different entangled processes. One to reduce activity during periods where the sensors suck. Another to prevent continued activity when the sensors suck. Another that handles waste. Another that starts up ML algorithms during the downtime to take advantage of the freed-up processing. Another that does data backup. The muscles use the downtime to start construction. Basically all over the body everyone is starting to get to work. It's like that tradeoff problem that gwern talks about with using notropics, where each one improves one thing but causes problems in other areas. So basically, it isn't a question of whether or not you need sleep from a theoretical process perspective. You don't, if you had a different design. But now sleep isn't just the reduce activity time because its night adaption. It's all tied up in everything else. You shorten the amount you sleep? You die younger, because you cancelled the bodies maintenance period. [1]: Which dolphins are kind of doing.
  - randcraw 9y ago
    I think nature's solution to this kind of inefficiency arises by adopting a new social behavior rather than evolving a new DNA-based physical ability. It's easier and faster for a group of animals to appoint a guard to protect others during sleep than for the species to evolve a superior brain.
- Tharkun 9y ago
  The blood/brain barrier makes it difficult to deliver chemical means to the brain.
- zip1234 9y ago
  Or maybe some sort of mechanical pumping system? If it takes too much energy away from the brain to both remain awake and clear those proteins, a mechanical pump that is powered externally could solve that energy problem. (I'm only half joking--we already have mechanical means of replacing other biological functions such as a dialysis machine).
  - che_shirecat 9y ago
    Along this line of thinking, if we knew exactly what was happening in the brain during sleep, could we speed up the process with mechanical/chemical means? Could we turn off brain functions to shrink the cells (or co-opt the existing sleep process and do this after one has fallen asleep), do the cleaning process (faster, while keeping the same effect) then wake up for maybe 30 minutes total of "sleep" a day? I personally don't think it's possible, at least for another century or so, because it's attempting to hack a body function and do it better (faster) than the body naturally does it (a dialysis machine is a poor substitute for a real kidney). Is there any example of a biomedical tech advancement where some part or mechanism in our body was augmented/replaced with something works better than the original?
    - twinkletwinkle 9y ago
      The elbow surgery that baseball pitchers sometimes need. There were reports of pitchers throwing better afterwards, which led to young aspiring pitchers with healthy elbows requesting the surgery. I don't know much about the actual process, I was just reading an article about the ethics of operating on a normal elbow in order to gain some competitive advantage.
      - ghthor 9y ago
        This doesn't sound far fetched at all. Small injuries are a way to focus the body to enter a recovery phase where the end result is a bone/tissue configuration that is strong and less likely to be repeat injured. Martial Artists have been practicing this type of body modification for centuries to bones, ligaments, muscles, and minds. I've experienced it through my own personal knee surgeries. And I wouldn't be surprised if in the future we offer body enhancements to healthy indivuals through surgery that will improve performance or long term health.
crx29a 9y ago
They want you to sleep, else: toxins.
- JacksonGariety 9y ago
  Yes. Certainly a conspiracy.
Overtonwindow 9y ago
Random thought: Could dreams be a result of the processing of toxins? In the same way some "toxins" cause us to hallucinate etc. so too could these toxins, as a side affect of processing?
- clavalle 9y ago
  >The team discovered that this increased flow was possible in part because when mice went to sleep, their brain cells actually shrank, making it easier for fluid to circulate. It could be that the brain needs to fire up for short periods in order to help pump the increased fluid out to prepare for another rinse.
  - clort 9y ago
    What I thought of, when I read that was that perhaps the shrinking is related to reduced blood flow or reduced blood absorption (does blood pressure raise or lower during sleep?) and this is also related to sleep itself, in the same way that a chokehold causes unconsciousness by restricting the oxygen reaching the brain
  - tbirrell 9y ago
    Hmm... Interesting, almost like a heart. Expand, contract, expand, contract. That could be why we have multiple dreams a night.
  - deleted 9y ago
    [deleted]
- e40 9y ago
  I read somewhere in the last 10 years that dreams were practice for real life situations. After hearing that, when I awake in the middle of a dream, I always test that hypothesis, and sure enough, sometimes is quite plausible.
  - Namrog84 9y ago
    Most of my dreams involve a lot of supernatural events and scenarios that'd be quite unlikely in real life. Am I preparing for a day soon where magic, superpowers and other super natural events become real?
ramshanker 9y ago
Wild analogy.... Inference machines cleanup the neutral model itself when put to relax. Wait, are there any Neural Nets out there, which produce toxic "weights" to be discarded later, If not than we are far from copying the real glucose based neural networks. /Imagination
- m3kw9 9y ago
  I think rest in human term is different than machines. Also, that is just a cleanup mode, machines can induce that with or without "rest"
  - Apocryphon 9y ago
    Yeah, all organs produce waste chemicals, the brain is no different in that respect.
- jacquesm 9y ago
  > Wait, are there any Neural Nets out there, which produce toxic "weights" to be discarded later That's what 'dropout' is for ;)
lmkg 9y ago
There's already research that being sleep-deprived has similar cognitive effects to being drunk, especially with regards to driving safety. This new result implies that may be more than a coincidence, as the biological underpinnings may be similar.
vkat 9y ago
Makes me think sweeping is analogous to a halt the world garbage collector.
jwilliams 9y ago
A related and quite recent piece of research - Stimulating toxin cleanup via brain stimulation using pulsed light. Has been used to treat Alzheimer symptoms in mice models. Last I heard was being fast-tracked to humans. http://news.mit.edu/2016/visual-stimulation-treatment-alzheimer-1207 http://news.mit.edu/2016/visual-stimulation-treatment-alzhei... "This treatment appears to work by inducing brain waves known as gamma oscillations, which the researchers discovered help the brain suppress beta amyloid production and invigorate cells responsible for destroying the plaques."
- bcherny 9y ago
  For those that prefer research in podcast form: http://www.radiolab.org/story/bringing-gamma-back/ http://www.radiolab.org/story/bringing-gamma-back/
  - e40 9y ago
    A great podcast, btw. That specific episode and in general. I wonder if this brain hack will have unwanted side effects. That is, I wonder if using the light trick could cause the normal processing to either not happen or happen less often. This is really exciting research, though, and I really hope it is effective in humans like it is in mice.
- bcherny 9y ago
  I wonder if a laptop/phone screen is capable of producing this specific frequency of pulsed light.. Edit: FWIW: https://www.youtube.com/watch?v=uaiiJsfgP58 https://www.youtube.com/watch?v=uaiiJsfgP58
  - simcop2387 9y ago
    most displays still being 60hz i don't think it'll work well. But a 120hz or 240hz should be able to do it pretty well I'd think.
    - apk-d 9y ago
bitexploder 9y ago
The actual research is quite interesting. Sleep disorders themselves are fascinating. There is evidence that TBI (traumatic brain injury) can cause lasting sleep cycle disruption. Perhaps sleep disruption and TBI is a much bigger factor in the lasting impact of TBI than previously thought. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482689/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482689/). Article review: This is pretty good science reporting, actually providing a link to the study being referenced. My one nit is the use of the word "Toxins". That is a trigger word for me that immediately makes me suspicious of the reporting. Scientific papers about the human body very rarely if ever use the word "Toxins" preferring precise terminology such as "brain waste products" or just keeping to the chemical names at hand. "Toxins" is one of those normative layman words that gets used to sweep up all sorts of ill-conceived explanations and pseudo-science.
- pnathan 9y ago
  Yes, "toxic" and "toxins" are incredibly vague. I loathe the use of those words, as they are both scary and nearly meaningless.
  - nsxwolf 9y ago
    When I see "toxins" I just stop reading. I assume the article is an ad for a juice cleanse.
    - bovermyer 9y ago
      This seems... extreme, to me. Completely ignoring a thing because of an imperfection could narrow one's depth of experience.
      - nsxwolf 9y ago
        It's mostly involuntary by now. My BS detectors have been trained on that term my whole life. It's in the same category in my brain as "homeopathic".
afarrell 9y ago
My alma mater has a saying: "sleep is for the weak". If you go to a university with that slogan, here is one more reason why it is foolish. If you want to learn effectively and work efficiently, take care of your body and take care of your brain.
- piannucci 9y ago
  Hey, my alma mater has that slogan too... oh, hi, afarrell.
  - throwaway6497 9y ago
    Which schools are these?
    - jpm_sd 9y ago
      MIT
      - csallen 9y ago
        I once read that collective sleep deprivation is "not a thing." After graduating from MIT with a particularly grueling and sleepless final semester, I slept 12 hours a day for two weeks straight. (I normally sleep 6-7 hours before waking up on my own.)
      - Hydraulix989 9y ago
        It's a shame what these "top" schools can get away with because of the sacrifices some people are willing to put themselves through to get a coveted degree.
        Helmet 9y ago
        Can't argue with the results. http://libguides.mit.edu/c.php?g=176016&p=1159581 http://libguides.mit.edu/c.php?g=176016&p=1159581
Yabood 9y ago
I learned about this from the Learning how to learn class on Coursera. Can't recommend it enough. https://www.coursera.org/learn/learning-how-to-learn https://www.coursera.org/learn/learning-how-to-learn
- akprasad 9y ago
  I went through the course on your recommendation. Thanks, it was great! Apparently much of it based on Oakley's book A Mind For Numbers, which I'll try to read soon. Much of the content also reminded me of Josh Waitzkin's The Art of Learning. A related thread elsewhere on HN [1] also suggests Make It Stick by Peter Brown. [1]: https://news.ycombinator.com/item?id=8815148 https://news.ycombinator.com/item?id=8815148
  - rimliu 9y ago
    Just today I got notification from iTunes that her new book "Mindshift" (which I had preoredered) is out. Her new course with the same name is on Coursera too https://www.coursera.org/learn/mindshift/home https://www.coursera.org/learn/mindshift/home After first week not sure how much does it overlap with "Learning how to learn".
empath75 9y ago
This should worry all the people taking adderall and modafinil to be more productive.
- deathhand 9y ago
  Additionally-when ingesting any number of substances that changes cognition my personal antecedent to add is that 'I just don't feel right' unless I nap. This is true for all things one would imbibe to 'escape reality'.
- prodtorok 9y ago
  Why?
  - che_shirecat 9y ago
    because you're taking on significant health risks ("toxin" buildup as mentioned here among other things) by not sleeping, health risks that normally wouldn't be there because of the natural fatigue and lethargy that would force an unmedicated person (however dedicated) to drift off
    - deleted 9y ago
      [deleted]
    - Jipha 9y ago
      Sure, but not everyone is taking them to avoid sleep. Regular users primarily use them to boost productivity during the day, followed by normal sleep.
      - che_shirecat 9y ago
        True, that could be one way of framing the whole "using adderall/modafinil for productivity" issue. What is a "regular user" though? Someone with ADHD taking adderall in the morning to boost the "executive function" of his/her brain during the day? (as someone with ADHD, adderall sedates my hyperactive brain as opposed to its intended effect, look up the stimulant paradox for more on this) Someone who takes adderall the night before a big test to pull an all-nighter of productive studying? I've personally never heard of anyone (without ADHD) who regularly takes amphetamines to boost waking-hour productivity. Modafinil has related but different effects, regular modafinil users take it to offset the reduced mental performance brought about by sleep deprivation. There might be some nootropic effects of modafinil unrelated to its wakefulness promoting effect (cognition-wise), but like all nootropics, whether there's any actual increase in waking-hour cognitive ability is debatable.
kgdinesh 9y ago
so sleeps are basically GC pauses.
joering2 9y ago
It always amazes me to read articles like this. How come I don't need more than 3 hours of sleep a day and its been like that for over 15 years now? I sleep "late hours". I go sleep around 8am and wake up around noon. I don't eat breakfast just coffee. I work most of the day on different projects, eat quite large dinner at 8pm, then every day go for 45 min to the gym, around 10pm and then 20 min walk. After that its about midnight and I start working. I don't get tired until 5am but then 2 glasses of water "wake me up". By 8am I'm in bed truly tired. I been running this schedule for 15 years now, no symptoms of nothing. I don't smoke and don't drink btw. I barely watch TV (never found anything interesting; I take breaks on my PC watching some travel-related documentaries) Edit: perhaps once a month I feel truly tired and usually on the weekend, I tend to sleep about 8-10 hours. But that doesn't happen often.
- gh1 9y ago
  Wow that sounds amazing. Did you see anyone (like a doctor or a researcher) and ask for an explanation of how you can do this?
  - joering2 9y ago
    No I didn't ask the doctor. Go thru regular checkup once a month and nothing came up so I don't bother. As far as I remember it wasn't always like that. Eventually at some point around my 20s I start working more and more hours and never got "break". Eventually I think my body got used to _knowing_ how many hours per night it can expect and adjusted. That or perhaps a heart attack is coming any day now at 35 (knock on the wood)
    - gh1 9y ago
      I sure hope that you stay at the best of your health. I am very curious about your capability because I always told myself that sleep is very important to my performance, concentration and overall well being. How do the people in your life (e.g. friend, family) generally react when they find out that you sleep so little?
- colmvp 9y ago
gdubs 9y ago
I'm currently reading Arianna Huffington's "The Sleep Revolution". If you're interested in more stuff like this, it's pretty good. It's definitely made me more mindful of winding down and night and getting plenty of sleep. One thing in particular that stood out is the rise in cortisol associated with lack-of-sleep, and cortisol's relationship to gaining fat; having hit a couple of rocky weeks sleep due to young kids at home, this was particularly relevant to me. I now rank sleep as pinnacle in terms of health / fitness training, mental well-being, creativity, etc.
- djsumdog 9y ago
  There have been two Vox articles about people who are biologically late sleepers are often viewed as "lazy." It's sad considering the current state of sleep deprivation throughout the western world. I hate being up early for work. I am 9am scrum since our team is spread out over the planet and it's truly painful. The right attitude is not "you should get to bed at a reasonable time," since I often get bursts of productivity between 11pm and 4am. I'm probably the most productive in that window. Choosing jobs and career paths based on your sleeping pattern (and overall heath) should be encourage more over money or benefits or retirement or all of those other bullshit traps: http://khanism.org/perspective/trapped-in-the-cubical/ http://khanism.org/perspective/trapped-in-the-cubical/
- deleted 9y ago
  [deleted]
bjornsing 9y ago
I'd be very surprised if it turns out that there's not a major "computational" element to sleep. Sure, it may be difficult to circulate fluid through a waken beings brain, but I think evolution could have managed. If the "computational resource" is needed for something else though (like running backprop over your neural networks or something :P)... That to me is the only reasonable explanation for the huge evolutionary cost most creatures pay for sleep.
- slmrnz 9y ago
  Reminds me of the good old days of defragging a Windows hard drive :)
  - erikj 9y ago
    It's more like stop-the-world garbage collection.
- nkrisc 9y ago
  But evolution doesn't "manage" anything. Evolution often plateaus at "good enough." I think this is the risk in the computer metaphor for the brain. Computers have designers that try to optimize them, brains do not.
  - zachkatz 9y ago
    As far as we know... It's possible that our invention of computers was and continues to be a slow brew to simulate something innate within us...
- wahern 9y ago
  What's the huge cost? Most land reptiles and mammals spend most of their time idle anyhow, including humans. In many cases sleep is arguably preferable as the animal is less likely to get itself eaten. If you're not foraging or reproducing, your best bet is to hide and stay still. Because animals, especially land animals, tend to be specialized for particular parts of the day or for other scenarios which preclude 24/7 activity, there's not much that can be done in that idle time. Except improve neurological function, apparently. Animals that need to be constantly in motion have other adaptations. For modern humans the cost can be immense according to our cultural calculus. I'm not sure it's an evolutionary cost. Only time will tell whether those burning the midnight oil have better reproductive success.
ZanyProgrammer 9y ago
It's interesting that in almost every sleep related article I've read on HN, the overwhelming majority of people who respond about their personal life say that they hate getting up 'early'-for various definitions of early. Surely there are programmers who like getting up early?
- seizethecheese 9y ago
  Perhaps they aren't posting on message boards during the workday.
- nightbrawler 9y ago
  When I was younger I preferred staying up late and working and it allowed me to get a lot done. As I've gotten older and now have a family, things have flipped and now I much prefer to start my work day early, usually around 6am. This gives me more family time in the afternoon/evenings.
  - tigershark 9y ago
    Pretty much useless for me given that my wife rarely it's at home before 7.30 and I'm there before 5..
- shocks 9y ago
  I like getting up early, where early is defined as 6am to 6:30am.
- Klockan 9y ago
  I like getting up early since everyone else likes getting in late and leaving late. For example if I arrive at 6 and they at 10 I will get 4 undisturbed hours of work. To get the same amount on the other end I would have to arrive at 3 in the evening.
- rootusrootus 9y ago
  I like getting up around 5:30 or so. Puts me outside the heaviest traffic times and gives me a few hours in the morning of uninterrupted time to mind meld with the computer. And then I get to leave 'early' in the afternoon and enjoy my free time and plentiful daylight.
looserof7 9y ago
If removing waste materials is the only purpose why we sleep and if somebody found a way to remove the same, then I would never sleep again, because I got to learn too many things.
convales 9y ago
www.ted.com/talks/jeff_iliff_one_more_reason_to_get_a_good_night_s_sleep
convales 9y ago
Learned about this few years ago here is the link https://www.ted.com/talks/jeff_iliff_one_more_reason_to_get_a_good_night_s_sleep https://www.ted.com/talks/jeff_iliff_one_more_reason_to_get_...
melvinmt 9y ago
I thought this was already common knowledge? I remember reading about this about 3 years ago. Specifically in this article about coffee naps http://www.vox.com/2014/8/28/6074177/coffee-naps-caffeine-science http://www.vox.com/2014/8/28/6074177/coffee-naps-caffeine-sc... which links to this Harvard article: http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/why-do-we-sleep http://healthysleep.med.harvard.edu/healthy/matters/benefits...
- metamet 9y ago
  Well, this article is from October 2013...
  - melvinmt 9y ago
    Ah, missed that :)
lucaspiller 9y ago
This article is from 2013. Has there been any further research published since then?
eof 9y ago
I bet meditation, or a state that can be brought on by meditation, has this same effect.
gh1 9y ago
I have heard of at least three believable theories of why we sleep. - To turn short term memory into long term memory, to consolidate long term memory, and prepare the brain to learn new things. - To clean the brain of harmful waste products (which is what this article says. By the way, it is old and from 2013). - An evolutionary artifact of energy conservation in resource-low ecosystems. Are there some other theories too?
scandox 9y ago
IIRC the story Manhole 69 by JG Ballard references a requirement to divert neurotoxins in men whose sleep centres were disconnected/cauterised. Ballard I presumed was just speculating. But based on his relatively high level of scientific knowledge I imagined it was rooted in some sort of real world science. That story was written in the 1960s...so has the state of research on this remained slow or was Ballard just making a lucky guess?
Mz 9y ago
Any sufficiently advanced technology is indistinguishable from magic. s/technology/science https://en.wikipedia.org/wiki/Clarke%27s_three_laws https://en.wikipedia.org/wiki/Clarke%27s_three_laws At some point, people on HN will get over their fear of words like "toxins" and embrace the Tao Te Woo as the advanced science it is.
Puts 9y ago
Maybe looking for the reason we sleep is the wrong way to look at it? What if being asleep is the default state for any organism? Sleeping require much less energy. The only reason to be awake is to eat and reproduce. For any animal there is probably an optimal ratio between sleep and hunt/reproduction where sleep is the most favorable.
- superasn 9y ago
  That's quite an insightful comment. Reminds me of an article about sea squirts who literally eat their brain once they are settled and have no longer a use for moving [1] [1] https://www.psychologytoday.com/blog/choke/201207/how-humans-learn-lessons-the-sea-squirt https://www.psychologytoday.com/blog/choke/201207/how-humans...
- JimboOmega 9y ago
  But sleeping makes you much more vulnerable to predation, and really doesn't save much more energy vs. quiet/restful wakefulness. Just think of how disoriented you are when something wakes you up in the middle of night - that's a definite biological cost if that thing is something threatening to you. And of course, never mind creatures that have gone as far as the 50/50 brain adaptation (IE Dolphins), they simply have to be at least partially awake all the time.
  - ghthor 9y ago
    This could be why meditation is such a useful state for our brain to be in. A combination of wakeful, highly aware of surroundings, yet peace and calm enough for waste to be cleaned up.
- smallgovt 9y ago
  This strikes me as the type of comment that sounds artificially 'deep' but has no constructive or logical basis. What does 'default state' even mean in this context? The fact is we naturally sleep sometimes and we're awake at other times. If you're suggesting there's no reason for sleep other than conserving energy, that's patently false. The (assumed) primary motive here is to find a way to sleep less. We already have ways to force wakefulness. We now need to find ways to mitigate negative side effects hence the research on various health functions sleep contributes towards.
jmagaro88 9y ago
Should be noted that the article is from 2013 in the title
- cpncrunch 9y ago
  This same article was actually posted here a few years ago, and commented on extensively: https://news.ycombinator.com/item?id=10061833 https://news.ycombinator.com/item?id=10061833

420 points by phatboyslim 9y ago

rl3 9y ago

Title should be updated to reflect 2013.

djsumdog 9y ago
Yes, I remember seeing this on here several months ago. Still good for all the people who may have missed it.

mabbo 9y ago

> The process is important because what's getting washed away during sleep are waste proteins that are toxic to brain cells, Nedergaard says. Evolution found a nice little optimum in sleep that works pretty well- use less energy during a time of the day that isn't a very efficient time to be awake while also cleaning out the brain. This could be interesting for future research. Could we find chemical means to remove those waste proteins?

bryondowd 9y ago
There's an interesting concept. I wonder what the trade-off would be. How much efficiency would it cost to clean the brain continually rather than in a dedicated sleep cycle? Would it even be possible to process these toxins while maintaining consciousness? I'm sure there could be huge benefits for many modern lifestyles to trade heavily on reaction speed and/or lightly on IQ for 50% more waking hours. Or even 25% more waking hours, if you just cut the need for sleep in half, over the long term.
- mrzool 9y ago
  Why force things? I don't want 50% more waking hours. I enjoy my sleep tremendously.
  - bmelton 9y ago
    I suspect (but do not know) that you enjoy your sleep because of its restorative effect. If you could obviate the need for the restorative effect, and instead just always feel newly restored, would you still enjoy going to sleep for no reason? Personally, I dislike the need for sleep. I put it off for as long as I can manage, and try to get as little of it as I can get away with. For me, I have a hard time functioning well with less than 4 hours a night, but anything more then 5.5 hours and I feel like I've thrown the day away. The idea of voluntarily checking out from the world isn't as relaxing to me as picking up a book to read, or learning something new, or doing something productive that isn't work/startup-related. Either way, I assume that nobody would force you to take a drug that you didn't want to take.
    - eckza 9y ago
      Oh my god, think of what this would do to commerce, in terms of a capitalist society. Suddenly, you can take a drug that decreases your need for sleep by 50%. People only need 4h of sleep per night now, for a full nights' sleep - 3h, if you're willing to skimp a little, 2h isn't unheard of (in the way that only getting 4h of sleep a night, now, isn't unheard of either). Suddenly, there's a significant advantage in the hands of everyone willing to take this drug. Students are expected to study more and harder, because they don't need 8h of sleep every night. Entrance exams to schools get more difficult. Software developers are now enticed to work longer hours - longer hours than they already are. Labor / shift workers (hospitality / food industry) are expected to work longer shifts, and they have to, because businesses have to be open longer because more people are awake for more of the day. Now, also, you have to consider: this is just sleep, in terms of brain repair. Your body has to put itself back together every night, too - repairing microscopic muscle tears, fixing bruises, etc etc etc. Your body would probably start slowly falling apart on 2-3h of sleep per night, even if your mind was fully rested. I really, really hope this doesn't happen.
      - ChuckMcM 9y ago
        It is entirely possible that it would evolve differently, perhaps given that not everyone would be available during the 'dark' hours you might see a society evolve into dual function, where 8 hours were for 'working' and 8 hours were for 'community/family' with 8 hours split into two 4 hour segments as 'transition times'.
- clort 9y ago
  some birds (and dolphins?) sleep one hemisphere at a time, so that they can keep flying
- JoshCole 9y ago
  I think from the evolutionary perspective, being active during a time of low fitness gets punished. So if there was an adaption that tended to paralyze something when it was dark out, that gets selected for even though obviously given optimal decisions not being paralyzed is better. Which, if you think about it, is kind of what is happening with sleep. So I imagine the trade-off isn't as severe as someone might guess; it's definitely theoretically possible to run entirely without sleep with the right hardware. For example, lets say sleep was fundamental to cognition. If you were willing to have redundant hardware, you could run two brains and just take turns sleeping them [1]. So that probably gives something of an upper-bound to efficiency. The problem is that a lot of stuff is getting built on top of these things. Scheduled downtime is getting used by other adaptions. Things like handling 'garbage collection' or 'waste collection' inline get shunted away to the downtime to improve response times. This keeps happening. Over short periods there are going to be plenty of cases where being paralyzed isn't optimal. What if something shows in the night? Long term though if the creature is continually staying active when its at disadvantage that's really bad. So additional penalties accrue to force the issue. Then the original 'purpose/benefit' starts getting lost. Things get messed up. Enough adaptions end up taking advantage of the fact that the downtime existed that now there is so much benefit to it for reasons unrelated to its initial creation that it starts becoming worth doing even at times where light levels aren't an issue. So now when you try to mess with sleep, you're not just messing with one little thing. You're messing with a whole bunch of different entangled processes. One to reduce activity during periods where the sensors suck. Another to prevent continued activity when the sensors suck. Another that handles waste. Another that starts up ML algorithms during the downtime to take advantage of the freed-up processing. Another that does data backup. The muscles use the downtime to start construction. Basically all over the body everyone is starting to get to work. It's like that tradeoff problem that gwern talks about with using notropics, where each one improves one thing but causes problems in other areas. So basically, it isn't a question of whether or not you need sleep from a theoretical process perspective. You don't, if you had a different design. But now sleep isn't just the reduce activity time because its night adaption. It's all tied up in everything else. You shorten the amount you sleep? You die younger, because you cancelled the bodies maintenance period. [1]: Which dolphins are kind of doing.
- randcraw 9y ago
  I think nature's solution to this kind of inefficiency arises by adopting a new social behavior rather than evolving a new DNA-based physical ability. It's easier and faster for a group of animals to appoint a guard to protect others during sleep than for the species to evolve a superior brain.
Tharkun 9y ago
The blood/brain barrier makes it difficult to deliver chemical means to the brain.
zip1234 9y ago
Or maybe some sort of mechanical pumping system? If it takes too much energy away from the brain to both remain awake and clear those proteins, a mechanical pump that is powered externally could solve that energy problem. (I'm only half joking--we already have mechanical means of replacing other biological functions such as a dialysis machine).
- che_shirecat 9y ago
  Along this line of thinking, if we knew exactly what was happening in the brain during sleep, could we speed up the process with mechanical/chemical means? Could we turn off brain functions to shrink the cells (or co-opt the existing sleep process and do this after one has fallen asleep), do the cleaning process (faster, while keeping the same effect) then wake up for maybe 30 minutes total of "sleep" a day? I personally don't think it's possible, at least for another century or so, because it's attempting to hack a body function and do it better (faster) than the body naturally does it (a dialysis machine is a poor substitute for a real kidney). Is there any example of a biomedical tech advancement where some part or mechanism in our body was augmented/replaced with something works better than the original?
  - twinkletwinkle 9y ago
    The elbow surgery that baseball pitchers sometimes need. There were reports of pitchers throwing better afterwards, which led to young aspiring pitchers with healthy elbows requesting the surgery. I don't know much about the actual process, I was just reading an article about the ethics of operating on a normal elbow in order to gain some competitive advantage.
    - ghthor 9y ago
      This doesn't sound far fetched at all. Small injuries are a way to focus the body to enter a recovery phase where the end result is a bone/tissue configuration that is strong and less likely to be repeat injured. Martial Artists have been practicing this type of body modification for centuries to bones, ligaments, muscles, and minds. I've experienced it through my own personal knee surgeries. And I wouldn't be surprised if in the future we offer body enhancements to healthy indivuals through surgery that will improve performance or long term health.

crx29a 9y ago

They want you to sleep, else: toxins.

JacksonGariety 9y ago
Yes. Certainly a conspiracy.

Overtonwindow 9y ago

Random thought: Could dreams be a result of the processing of toxins? In the same way some "toxins" cause us to hallucinate etc. so too could these toxins, as a side affect of processing?

clavalle 9y ago
>The team discovered that this increased flow was possible in part because when mice went to sleep, their brain cells actually shrank, making it easier for fluid to circulate. It could be that the brain needs to fire up for short periods in order to help pump the increased fluid out to prepare for another rinse.
- clort 9y ago
  What I thought of, when I read that was that perhaps the shrinking is related to reduced blood flow or reduced blood absorption (does blood pressure raise or lower during sleep?) and this is also related to sleep itself, in the same way that a chokehold causes unconsciousness by restricting the oxygen reaching the brain
- tbirrell 9y ago
  Hmm... Interesting, almost like a heart. Expand, contract, expand, contract. That could be why we have multiple dreams a night.
- deleted 9y ago
  [deleted]
e40 9y ago
I read somewhere in the last 10 years that dreams were practice for real life situations. After hearing that, when I awake in the middle of a dream, I always test that hypothesis, and sure enough, sometimes is quite plausible.
- Namrog84 9y ago
  Most of my dreams involve a lot of supernatural events and scenarios that'd be quite unlikely in real life. Am I preparing for a day soon where magic, superpowers and other super natural events become real?

ramshanker 9y ago

Wild analogy.... Inference machines cleanup the neutral model itself when put to relax. Wait, are there any Neural Nets out there, which produce toxic "weights" to be discarded later, If not than we are far from copying the real glucose based neural networks. /Imagination

m3kw9 9y ago
I think rest in human term is different than machines. Also, that is just a cleanup mode, machines can induce that with or without "rest"
- Apocryphon 9y ago
  Yeah, all organs produce waste chemicals, the brain is no different in that respect.
jacquesm 9y ago
> Wait, are there any Neural Nets out there, which produce toxic "weights" to be discarded later That's what 'dropout' is for ;)

lmkg 9y ago

There's already research that being sleep-deprived has similar cognitive effects to being drunk, especially with regards to driving safety. This new result implies that may be more than a coincidence, as the biological underpinnings may be similar.

vkat 9y ago

Makes me think sweeping is analogous to a halt the world garbage collector.

jwilliams 9y ago

A related and quite recent piece of research - Stimulating toxin cleanup via brain stimulation using pulsed light. Has been used to treat Alzheimer symptoms in mice models. Last I heard was being fast-tracked to humans. http://news.mit.edu/2016/visual-stimulation-treatment-alzheimer-1207 http://news.mit.edu/2016/visual-stimulation-treatment-alzhei... "This treatment appears to work by inducing brain waves known as gamma oscillations, which the researchers discovered help the brain suppress beta amyloid production and invigorate cells responsible for destroying the plaques."

bcherny 9y ago
For those that prefer research in podcast form: http://www.radiolab.org/story/bringing-gamma-back/ http://www.radiolab.org/story/bringing-gamma-back/
- e40 9y ago
  A great podcast, btw. That specific episode and in general. I wonder if this brain hack will have unwanted side effects. That is, I wonder if using the light trick could cause the normal processing to either not happen or happen less often. This is really exciting research, though, and I really hope it is effective in humans like it is in mice.
bcherny 9y ago
I wonder if a laptop/phone screen is capable of producing this specific frequency of pulsed light.. Edit: FWIW: https://www.youtube.com/watch?v=uaiiJsfgP58 https://www.youtube.com/watch?v=uaiiJsfgP58
- simcop2387 9y ago
  most displays still being 60hz i don't think it'll work well. But a 120hz or 240hz should be able to do it pretty well I'd think.
  - apk-d 9y ago

bitexploder 9y ago

The actual research is quite interesting. Sleep disorders themselves are fascinating. There is evidence that TBI (traumatic brain injury) can cause lasting sleep cycle disruption. Perhaps sleep disruption and TBI is a much bigger factor in the lasting impact of TBI than previously thought. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482689/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482689/). Article review: This is pretty good science reporting, actually providing a link to the study being referenced. My one nit is the use of the word "Toxins". That is a trigger word for me that immediately makes me suspicious of the reporting. Scientific papers about the human body very rarely if ever use the word "Toxins" preferring precise terminology such as "brain waste products" or just keeping to the chemical names at hand. "Toxins" is one of those normative layman words that gets used to sweep up all sorts of ill-conceived explanations and pseudo-science.

pnathan 9y ago
Yes, "toxic" and "toxins" are incredibly vague. I loathe the use of those words, as they are both scary and nearly meaningless.
- nsxwolf 9y ago
  When I see "toxins" I just stop reading. I assume the article is an ad for a juice cleanse.
  - bovermyer 9y ago
    This seems... extreme, to me. Completely ignoring a thing because of an imperfection could narrow one's depth of experience.
    - nsxwolf 9y ago
      It's mostly involuntary by now. My BS detectors have been trained on that term my whole life. It's in the same category in my brain as "homeopathic".

afarrell 9y ago

My alma mater has a saying: "sleep is for the weak". If you go to a university with that slogan, here is one more reason why it is foolish. If you want to learn effectively and work efficiently, take care of your body and take care of your brain.

piannucci 9y ago
Hey, my alma mater has that slogan too... oh, hi, afarrell.
- throwaway6497 9y ago
  Which schools are these?
  - jpm_sd 9y ago
    MIT
    - csallen 9y ago
      I once read that collective sleep deprivation is "not a thing." After graduating from MIT with a particularly grueling and sleepless final semester, I slept 12 hours a day for two weeks straight. (I normally sleep 6-7 hours before waking up on my own.)
    - Hydraulix989 9y ago
      It's a shame what these "top" schools can get away with because of the sacrifices some people are willing to put themselves through to get a coveted degree.
      - Helmet 9y ago
        Can't argue with the results. http://libguides.mit.edu/c.php?g=176016&p=1159581 http://libguides.mit.edu/c.php?g=176016&p=1159581

Yabood 9y ago

I learned about this from the Learning how to learn class on Coursera. Can't recommend it enough. https://www.coursera.org/learn/learning-how-to-learn https://www.coursera.org/learn/learning-how-to-learn

akprasad 9y ago
I went through the course on your recommendation. Thanks, it was great! Apparently much of it based on Oakley's book A Mind For Numbers, which I'll try to read soon. Much of the content also reminded me of Josh Waitzkin's The Art of Learning. A related thread elsewhere on HN [1] also suggests Make It Stick by Peter Brown. [1]: https://news.ycombinator.com/item?id=8815148 https://news.ycombinator.com/item?id=8815148
- rimliu 9y ago
  Just today I got notification from iTunes that her new book "Mindshift" (which I had preoredered) is out. Her new course with the same name is on Coursera too https://www.coursera.org/learn/mindshift/home https://www.coursera.org/learn/mindshift/home After first week not sure how much does it overlap with "Learning how to learn".

empath75 9y ago

This should worry all the people taking adderall and modafinil to be more productive.

deathhand 9y ago
Additionally-when ingesting any number of substances that changes cognition my personal antecedent to add is that 'I just don't feel right' unless I nap. This is true for all things one would imbibe to 'escape reality'.
prodtorok 9y ago
Why?
- che_shirecat 9y ago
  because you're taking on significant health risks ("toxin" buildup as mentioned here among other things) by not sleeping, health risks that normally wouldn't be there because of the natural fatigue and lethargy that would force an unmedicated person (however dedicated) to drift off
  - deleted 9y ago
    [deleted]
  - Jipha 9y ago
    Sure, but not everyone is taking them to avoid sleep. Regular users primarily use them to boost productivity during the day, followed by normal sleep.
    - che_shirecat 9y ago
      True, that could be one way of framing the whole "using adderall/modafinil for productivity" issue. What is a "regular user" though? Someone with ADHD taking adderall in the morning to boost the "executive function" of his/her brain during the day? (as someone with ADHD, adderall sedates my hyperactive brain as opposed to its intended effect, look up the stimulant paradox for more on this) Someone who takes adderall the night before a big test to pull an all-nighter of productive studying? I've personally never heard of anyone (without ADHD) who regularly takes amphetamines to boost waking-hour productivity. Modafinil has related but different effects, regular modafinil users take it to offset the reduced mental performance brought about by sleep deprivation. There might be some nootropic effects of modafinil unrelated to its wakefulness promoting effect (cognition-wise), but like all nootropics, whether there's any actual increase in waking-hour cognitive ability is debatable.

kgdinesh 9y ago

so sleeps are basically GC pauses.

joering2 9y ago

It always amazes me to read articles like this. How come I don't need more than 3 hours of sleep a day and its been like that for over 15 years now? I sleep "late hours". I go sleep around 8am and wake up around noon. I don't eat breakfast just coffee. I work most of the day on different projects, eat quite large dinner at 8pm, then every day go for 45 min to the gym, around 10pm and then 20 min walk. After that its about midnight and I start working. I don't get tired until 5am but then 2 glasses of water "wake me up". By 8am I'm in bed truly tired. I been running this schedule for 15 years now, no symptoms of nothing. I don't smoke and don't drink btw. I barely watch TV (never found anything interesting; I take breaks on my PC watching some travel-related documentaries) Edit: perhaps once a month I feel truly tired and usually on the weekend, I tend to sleep about 8-10 hours. But that doesn't happen often.

gh1 9y ago
Wow that sounds amazing. Did you see anyone (like a doctor or a researcher) and ask for an explanation of how you can do this?
- joering2 9y ago
  No I didn't ask the doctor. Go thru regular checkup once a month and nothing came up so I don't bother. As far as I remember it wasn't always like that. Eventually at some point around my 20s I start working more and more hours and never got "break". Eventually I think my body got used to _knowing_ how many hours per night it can expect and adjusted. That or perhaps a heart attack is coming any day now at 35 (knock on the wood)
  - gh1 9y ago
    I sure hope that you stay at the best of your health. I am very curious about your capability because I always told myself that sleep is very important to my performance, concentration and overall well being. How do the people in your life (e.g. friend, family) generally react when they find out that you sleep so little?
colmvp 9y ago

gdubs 9y ago

I'm currently reading Arianna Huffington's "The Sleep Revolution". If you're interested in more stuff like this, it's pretty good. It's definitely made me more mindful of winding down and night and getting plenty of sleep. One thing in particular that stood out is the rise in cortisol associated with lack-of-sleep, and cortisol's relationship to gaining fat; having hit a couple of rocky weeks sleep due to young kids at home, this was particularly relevant to me. I now rank sleep as pinnacle in terms of health / fitness training, mental well-being, creativity, etc.

djsumdog 9y ago
There have been two Vox articles about people who are biologically late sleepers are often viewed as "lazy." It's sad considering the current state of sleep deprivation throughout the western world. I hate being up early for work. I am 9am scrum since our team is spread out over the planet and it's truly painful. The right attitude is not "you should get to bed at a reasonable time," since I often get bursts of productivity between 11pm and 4am. I'm probably the most productive in that window. Choosing jobs and career paths based on your sleeping pattern (and overall heath) should be encourage more over money or benefits or retirement or all of those other bullshit traps: http://khanism.org/perspective/trapped-in-the-cubical/ http://khanism.org/perspective/trapped-in-the-cubical/
deleted 9y ago
[deleted]

bjornsing 9y ago

I'd be very surprised if it turns out that there's not a major "computational" element to sleep. Sure, it may be difficult to circulate fluid through a waken beings brain, but I think evolution could have managed. If the "computational resource" is needed for something else though (like running backprop over your neural networks or something :P)... That to me is the only reasonable explanation for the huge evolutionary cost most creatures pay for sleep.

slmrnz 9y ago
Reminds me of the good old days of defragging a Windows hard drive :)
- erikj 9y ago
  It's more like stop-the-world garbage collection.
nkrisc 9y ago
But evolution doesn't "manage" anything. Evolution often plateaus at "good enough." I think this is the risk in the computer metaphor for the brain. Computers have designers that try to optimize them, brains do not.
- zachkatz 9y ago
  As far as we know... It's possible that our invention of computers was and continues to be a slow brew to simulate something innate within us...
wahern 9y ago
What's the huge cost? Most land reptiles and mammals spend most of their time idle anyhow, including humans. In many cases sleep is arguably preferable as the animal is less likely to get itself eaten. If you're not foraging or reproducing, your best bet is to hide and stay still. Because animals, especially land animals, tend to be specialized for particular parts of the day or for other scenarios which preclude 24/7 activity, there's not much that can be done in that idle time. Except improve neurological function, apparently. Animals that need to be constantly in motion have other adaptations. For modern humans the cost can be immense according to our cultural calculus. I'm not sure it's an evolutionary cost. Only time will tell whether those burning the midnight oil have better reproductive success.

ZanyProgrammer 9y ago

It's interesting that in almost every sleep related article I've read on HN, the overwhelming majority of people who respond about their personal life say that they hate getting up 'early'-for various definitions of early. Surely there are programmers who like getting up early?

seizethecheese 9y ago
Perhaps they aren't posting on message boards during the workday.
nightbrawler 9y ago
When I was younger I preferred staying up late and working and it allowed me to get a lot done. As I've gotten older and now have a family, things have flipped and now I much prefer to start my work day early, usually around 6am. This gives me more family time in the afternoon/evenings.
- tigershark 9y ago
  Pretty much useless for me given that my wife rarely it's at home before 7.30 and I'm there before 5..
shocks 9y ago
I like getting up early, where early is defined as 6am to 6:30am.
Klockan 9y ago
I like getting up early since everyone else likes getting in late and leaving late. For example if I arrive at 6 and they at 10 I will get 4 undisturbed hours of work. To get the same amount on the other end I would have to arrive at 3 in the evening.
rootusrootus 9y ago
I like getting up around 5:30 or so. Puts me outside the heaviest traffic times and gives me a few hours in the morning of uninterrupted time to mind meld with the computer. And then I get to leave 'early' in the afternoon and enjoy my free time and plentiful daylight.

looserof7 9y ago

If removing waste materials is the only purpose why we sleep and if somebody found a way to remove the same, then I would never sleep again, because I got to learn too many things.

convales 9y ago

www.ted.com/talks/jeff_iliff_one_more_reason_to_get_a_good_night_s_sleep

convales 9y ago

Learned about this few years ago here is the link https://www.ted.com/talks/jeff_iliff_one_more_reason_to_get_a_good_night_s_sleep https://www.ted.com/talks/jeff_iliff_one_more_reason_to_get_...

melvinmt 9y ago

I thought this was already common knowledge? I remember reading about this about 3 years ago. Specifically in this article about coffee naps http://www.vox.com/2014/8/28/6074177/coffee-naps-caffeine-science http://www.vox.com/2014/8/28/6074177/coffee-naps-caffeine-sc... which links to this Harvard article: http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/why-do-we-sleep http://healthysleep.med.harvard.edu/healthy/matters/benefits...

metamet 9y ago
Well, this article is from October 2013...
- melvinmt 9y ago
  Ah, missed that :)

lucaspiller 9y ago

This article is from 2013. Has there been any further research published since then?

eof 9y ago

I bet meditation, or a state that can be brought on by meditation, has this same effect.

gh1 9y ago

I have heard of at least three believable theories of why we sleep. - To turn short term memory into long term memory, to consolidate long term memory, and prepare the brain to learn new things. - To clean the brain of harmful waste products (which is what this article says. By the way, it is old and from 2013). - An evolutionary artifact of energy conservation in resource-low ecosystems. Are there some other theories too?

scandox 9y ago

IIRC the story Manhole 69 by JG Ballard references a requirement to divert neurotoxins in men whose sleep centres were disconnected/cauterised. Ballard I presumed was just speculating. But based on his relatively high level of scientific knowledge I imagined it was rooted in some sort of real world science. That story was written in the 1960s...so has the state of research on this remained slow or was Ballard just making a lucky guess?

Mz 9y ago

Any sufficiently advanced technology is indistinguishable from magic. s/technology/science https://en.wikipedia.org/wiki/Clarke%27s_three_laws https://en.wikipedia.org/wiki/Clarke%27s_three_laws At some point, people on HN will get over their fear of words like "toxins" and embrace the Tao Te Woo as the advanced science it is.

Puts 9y ago

Maybe looking for the reason we sleep is the wrong way to look at it? What if being asleep is the default state for any organism? Sleeping require much less energy. The only reason to be awake is to eat and reproduce. For any animal there is probably an optimal ratio between sleep and hunt/reproduction where sleep is the most favorable.

superasn 9y ago
That's quite an insightful comment. Reminds me of an article about sea squirts who literally eat their brain once they are settled and have no longer a use for moving [1] [1] https://www.psychologytoday.com/blog/choke/201207/how-humans-learn-lessons-the-sea-squirt https://www.psychologytoday.com/blog/choke/201207/how-humans...
JimboOmega 9y ago
But sleeping makes you much more vulnerable to predation, and really doesn't save much more energy vs. quiet/restful wakefulness. Just think of how disoriented you are when something wakes you up in the middle of night - that's a definite biological cost if that thing is something threatening to you. And of course, never mind creatures that have gone as far as the 50/50 brain adaptation (IE Dolphins), they simply have to be at least partially awake all the time.
- ghthor 9y ago
  This could be why meditation is such a useful state for our brain to be in. A combination of wakeful, highly aware of surroundings, yet peace and calm enough for waste to be cleaned up.
smallgovt 9y ago
This strikes me as the type of comment that sounds artificially 'deep' but has no constructive or logical basis. What does 'default state' even mean in this context? The fact is we naturally sleep sometimes and we're awake at other times. If you're suggesting there's no reason for sleep other than conserving energy, that's patently false. The (assumed) primary motive here is to find a way to sleep less. We already have ways to force wakefulness. We now need to find ways to mitigate negative side effects hence the research on various health functions sleep contributes towards.

jmagaro88 9y ago

Should be noted that the article is from 2013 in the title

cpncrunch 9y ago
This same article was actually posted here a few years ago, and commented on extensively: https://news.ycombinator.com/item?id=10061833 https://news.ycombinator.com/item?id=10061833