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Brains Sweep Themselves Clean of Toxins During Sleep (2013) (npr.org)
420 points by phatboyslim on April 17, 2017 | hide | past | favorite | 167 comments

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.


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.

Yes, "toxic" and "toxins" are incredibly vague. I loathe the use of those words, as they are both scary and nearly meaningless.

Fun fact: toxin meant arrow long ago, for taxus, (bark tree ?) which bow were made of. The funny part is that that tree is .. toxic, it embeds alcaloids which can kill. The taxus philogenetic family was often a symbol of death for cultures, and people commited suicide using its "effects". Lastly, those familiar with oncology probably know paclitaxel/taxol; which are molecules derived from these alcaloids for their cytotoxig capabilities (forbid mitosis and induce apoptosis).

ps: in death you seek knowledge. #deadline

>Fun fact: toxin meant arrow long ago, for taxus, (bark tree ?) which bow were made of

Actually from ancient Greek "toxicon" (related to archery) which stems from "toxon" (bow, not arrow), that got into latin. The association (toxicon -> toxic as in poisonous) came due to the practice of using poisons in archery (to make for lethal arrowheads).

Greeks took the word from Scythians. Taxus, for the yew family of trees (poisonous), is related to that, but the transfer to latin as currently used was through "toxic(os)".

Yeah I skipped a beat on the bow -> poisonous arrows.

just a footnote to your fine comment: the origin of that particular drug is the Pacific Yew


this same tree, as you indicate, was also used by Native Americans for making hunting bows


I think the original taxol was made from Pacific Yew, but the synthesis is from another kind yielding a precursor molecule.

When I see "toxins" I just stop reading. I assume the article is an ad for a juice cleanse.

I understand, but be aware that neurotoxic and neurotoxin are words used in scientific literature. "Toxins" in the context of the brain is completely OK.

This seems... extreme, to me. Completely ignoring a thing because of an imperfection could narrow one's depth of experience.

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".

"homeopathic" is a specific term that denotes a specific discredited (pseudo)scientific concept, that has been analyzed.

"toxin" is an general term that encompasses many established entities as well as phony ones. When you see "toxin", you can ask "which toxin are you referring to?"

My go-to default is black widow venom. If I don't get any specifics, I always just assume that the juice cleanse will rid my system of spider poison.

Even if it's not recommending a juice cleanse, whenever I see the word "Toxin" in an article without context I assume that the post was most likely written for the layman and as such probably sacrifices accuracy for ease-of-comprehension.

When I see the term "Cloud", I do the same thing.

So, no weather forecasts for you?

Its not like I ever leave my basement.

It begs the question: is a few days of codeine or valium the brain equivalent of a "lemon juice / cayenne" cleanse?

Is valium/codeine induced sleep equivalent to the real thing?

Begs the question?

relatively common idiom (which may or may not be used correctly here :) : https://english.stackexchange.com/questions/305/what-does-th...

OP meant "raises the question."


A widely used scientific term.

Quite so. And the words "toxic" and "toxin" are used for every single snake oil solution/problem out there in relation to health. It's become a great example of a failure over time in scientific communication and how the common usage of terms has been rendered useless in meaning for the common person.

It's a tragedy, but it's what's happened.

Are you sure scientists don't use the term?

Consider: https://scholar.google.com/scholar?hl=en&q=toxins+brain&btnG...

I don't have more information. I just typed that in based on your comment.

In biology, toxins are compounds that cause injury. The wording in the article implies that all waste products removed by sleep are toxic, which is unlikely. Many chemicals removed by sleep probably are not toxins, at least perhaps, not until they accumulate and form obstructions, like Alzheimer plaques.

I can't disagree. Scientists clearly use the word, but I would say there is a great deal of specificity to their usage and a very general malleable unspecific usage in typical science journalism, but that is a lot to write out, sort of an 80/20 rule for using the word Toxins. Often enough you will be write, so don't treat it as an inviolate law, but a good rule of thumb perhaps?

> 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?

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).

The brain has a mechanical pumping system, check it out https://en.wikipedia.org/wiki/Cerebrospinal_fluid#Clinical_s...

Wow, didn't know that--pretty amazing!

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?

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.

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.

Tommy John surgery is what it's usually referred to, after the first pitcher to undergo the procedure in the 1970s.

It's pretty accepted that the surgery is not performance enhancing against the healthy baseline. Some pitchers come back throwing harder because they had significant impairment (wearing of the tendons) before.

You might be interested in the normal physiology of cerebrospinal fluid [0] and the disease hydrocephalus [1] that occurs when there is a blockage in the normal flow path. As a treatment for hydrocephalus, bypass shunts (made of tubing) are installed inside the skull that create a relief path for the fluid to flow. Unfortunately, they often get clogged with cells due to various scar formation and immune reactions -- designing better shunts is an active area of biomaterials research, and it's quite possible that an external pump could be an upgrade (though we first have to show that it has benefit...).

[0]: https://en.wikipedia.org/wiki/Cerebrospinal_fluid

[1]: https://en.wikipedia.org/wiki/Hydrocephalus

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.

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.

some birds (and dolphins?) sleep one hemisphere at a time, so that they can keep flying

Why force things? I don't want 50% more waking hours. I enjoy my sleep tremendously.

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.

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.

There's a (good, rather surreal at times) webcomic along these lines, PowerNap. Cyberpunk-ish future, just about everybody takes a drug to eliminate the need for sleep, protagonist is someone who's allergic to the stuff and is navigating life in a world where sleep itself is a disorder. (Plus strange dreamscape things) http://www.powernapcomic.com/d/20110617.html

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'.

I was thinking this as well. I suspect that it's impossible to predict, but I wouldn't think it unfathomable to imagine a world in which, with all the additional free time, society might evolve towards a more Italian ethos, in which we take longer lunches, and don't mind spending as much overall time 'at the office', though not necessarily working any more while there.

As an American, living in late capitalism, I do not see this as anything but extremely wishful thinking for 99% of the working population here.

But if this sort of thing ever does happen, then I absolutely hope that it goes down as you've described.

Yes, your anti-capitalist intentions were pretty clear from your earlier post. Put simply, I do not share your views on the subject.

That's fair. Sorry, I hope I didn't get too carried away. Thanks for the dialogue. :)

No need to apologize, I just don't agree.

In the time I've been alive, I've seen more and more employers gravitating towards fewer hours, more lenient work schedules, etc. My first job was basically a minimum of 10 hours a day, and 6, sometimes 7 days a week. Nowadays, companies (especially in tech, mind you) are realizing the difficulty in recruiting / training / keeping personnel and are competing on benefits to the extent that 'unlimited' vacation days, telework, longer maternity and paternity leaves, etc. And before the obvious counterargument is made, this isn't limited just to technology (though it does seem to be blazing the trail.) Tech, agriculture, finance, business, and any industry in which recruiting and keeping talent are tricky are basically trading dollars for perks, and often, the result of that is that employees get to keep more of their personal time for themselves.

Sure, this hasn't affected every industry, and for industries where labor is a commodity, it may never occur, but just as sure as you believe your scenario is the result of capitalism, I believe that the increase in perks / time / accommodation is the same.

That's a really interesting perspective, especially since you've brought up a lot of illustrations that I cannot disagree with. I think you really nailed it with the phrase,

> trading dollars for perks

And I suppose it also has to do a lot with how much leverage employees have against their employers. Those of us in tech have more leverage on average than, say, a hospitality worker.

It's a lot more nuanced than I had initially thought, for sure.

"It's a lot more nuanced than I had initially thought"

Most things are a LOT more nuanced than most people give credence to, and there's zero dishonor in acknowledging that. With almost every issue I've delved into (especially political ones), there are arguments for and against any given issue that I can't hand-wave away. I might prioritize some factors ahead of others, but just about every political issue in the world is a matter of tradeoffs, and there are very few obvious wins.

I agree with your assertion here that much of the strengths to be found in capitalism revolve around the notion of resolving power imbalances. For every good story I've read, somewhere, there's a terrifying story -- I'm reminded of the old Hazard county mine worker strikes, for example.

But while unions are ostensibly the surest fix in mitigating those power imbalances (in fostering leverage to the people), the more I look at them the more I realize that they need to be truly cooperative. Union power is real enough that there are places like Sweden which have no minimum wage, and yet still have high effective wages. But in America at least, unions with political power often exploit that political power towards complacency, corruption, and often trend towards being less effective stewards of their member interests. In essence, too much cooperation between unions and policy makers may yield counter-intuitive results that manifest in ineffective unions, which yields declining memberships, which yields power imbalances in favor of corporations.

The point, if I have one, is that while so many people get wrapped up in the idea of "unions bad" or "unions good", we lose the ability to objectively evaluate whether a given union is good or bad because we ideologically insist that they be a certain way. Similarly, evaluations of government, corporations, regulations, trade, capitalism, socialism, et al all falter as soon as we begin to put too much faith in the institution that we stop performing scientifically objective and individual evaluations upon them.

Thanks for the conversation, and in particular, for the open mind. It's always a pleasure to engage with someone who I know to be willing to adjust their opinions to facts, and while capitalism surely isn't always good, it definitely isn't always bad either.

Are you into Science Fiction? You may enjoy Nancy Kress' "Beggars in Spain." It's a story with a similar central thesis.

There's a Doctor Who episode that sort of goes there a little, https://en.m.wikipedia.org/wiki/Sleep_No_More_(Doctor_Who) . It isn't one of the better episodes and the main plot is rather ridiculous but it does touchy upon your argument tangentially.

I would guess that the brain also does some reorganization functions while you sleep, where redundant info is compressed, and resources are freed up so that you can reuse them. Being conscious a larger percentage of the time may inhibit this.

"Either way, I assume that nobody would force you to take a drug that you didn't want to take."

Like hell they won't. It will become a social and economic imperative before you know it.

> anything more then 5.5 hours and I feel like I've thrown the day away.

Statistically you are unlikely to be one of those people for whom 5-6 hours sleep daily is sufficient, so all you are doing to yourself is contributing to increased aggression, dulling of empathy and reduced impulse control that comes with insufficient sleep.

I worked for 6 years in a 100% remote position, 3 timezones away from my employer, so as such, I kept a loose schedule. Eventually, I adopted the practice of just going to bed when I was tired, and waking up whenever I woke up. Sure, sometimes I was woken up by noises outside or what have you, but when I'd wake up on my own, usually it was between 4.5 to 5 hours from when I went to bed.

I wasn't going to bed at regular hours, and I wasn't waking up to an alarm, so I guess I am in that group (also, I don't have increased aggression or impulse control, but I don't know how I'd measure empathy). That said, I did not realize that I was statistically rare, so thanks for pointing out that maybe my 5 hours a night advice isn't applicable to others. Regardless of the amount of time involved in sleeping, I still would prefer not to have to take it, if that were an option.

If you genuinely are one of those people that can deal with that much sleep and still function normally then fair enough, kudos to you (and I'm a little jealous).

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.

The blood/brain barrier makes it difficult to deliver chemical means to the brain.

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.

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.

>This strikes me as the type of comment that sounds artificially 'deep' but has no constructive or logical basis

A bizarro thing to say, given that the parent gave several arguments that make sense from an evolutionary/physical viewpoint, like "sleeping requires much less energy" and "the only reason to be awake is to eat and reproduce".

>What does 'default state' even mean in this context?

The state that requires the less energy expenditure? Similar to a rest/equilibrium state in physics?

> The state that requires the less energy expenditure? Similar to a rest/equilibrium state in physics?

That's a very reasonable definition. Taking that into account, let's revisit the context of the parent comment: "What if being asleep is the default state for any organism?" What do you mean "what if"? "What if <insert obviously true statement>" is not a constructive or insightful question.

> A bizarro thing to say, given that the parent gave several arguments that make sense from an evolutionary/physical viewpoint, like "sleeping requires much less energy" and "the only reason to be awake is to eat and reproduce".

Repeating myself: If you're suggesting there's no reason for sleep other than conserving energy, that's patently false.

>Taking that into account, let's revisit the context of the parent comment: "What if being asleep is the default state for any organism?" What do you mean "what if"? "What if <insert obviously true statement>" is not a constructive or insightful question.

Well, assuming it's true, it's not that "obvious". And even if it is obvious to e.g. a biologist, it's not at all obvious to a layperson.

In fact it's so "not obvious" that you didn't even consider it valid when the parent said it (I merely clarified it further).

>Repeating myself: If you're suggesting there's no reason for sleep other than conserving energy, that's patently false.

Why repeat that though? It's not as is somebody claimed it.

What parent said (and I clarified) was whether sleep is the default state of an animal, and everything else is a deviation from that default to achieve a specific (reproductive etc) purpose.

So not only we did NOT say that "there's no reason for sleep other than conserving energy", but we explicitly said something close to being the opposite: that the only reason to be awake is to "eat and reproduce".

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...

My cats figured this out quite a while 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.

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.

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.


"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."

For those that prefer research in podcast form: http://www.radiolab.org/story/bringing-gamma-back/

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.

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

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.

Funny thing - the video is actually 30 FPS (to check, right click -> stats for nerds). You need to be running at 80 FPS to display a 40hz pulse (intuitively, each black-white cycle takes at least 2 frames to render).

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.

Hey, my alma mater has that slogan too... oh, hi, afarrell.

How do you feel, in retrospect, about 6.004? On the one hand, amazing class that takes you through multiple layers of abstraction. On the other hand, why oh why did they set the labs to be due at 6am?

(Of course, you could justly ask why oh why my sophomore-year-self didn't exercise discipline and cut myself off trying to improve my beta.)

Which schools are these?


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.)

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.

I'm confused. Where are the sleeping habits of the people in the list you linked?

Oh, right, there are none.

Some of it is the school's fault. Some of it is the fault of the particular student culture at the school.

I always believed that line is intended to be sarcastic.

In the words of Monty Python: It is a silly place.

Given that it was said without a sarcastic tone by people who irregularly stayed up until 4 am or whenever, I don't know how you got that interpretation.

It's essentially gallows humour.

Except its people encouraging each other in self-destructive behavior.

So... gallows humour.

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

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.

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?

>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.

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

Hmm... Interesting, almost like a heart. Expand, contract, expand, contract. That could be why we have multiple dreams a night.

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.

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?

Perhaps if you where out hunting & gathering instead of watching movies, reading books and playing videogames your dreams would be more "real".

bkkssnn hit the nail on the head, but I'll leave this here:


as a reply to your snarkiness.

Perhaps you missed the "sometimes"...

This reminds me of how they used GTA V to train driverless cars.

If dreams only were the result of some cleanup process (i.e. just arbitrary neurons firing), I imagine they would be a lot less coherent and all events would be (stochastically) independent. While dreams usually don't much make a huge lot of sense, they are sometimes quite realistic and "past" events seem to influence "later" events.

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

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

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 After first week not sure how much does it overlap with "Learning how to learn".

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.

I remember my friend mentioned to me she might have a mutation in the DEC2 gene (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884988/) because she usually goes to bed around 2 am and wakes up at 6-7 am, and has been doing it throughout her life. And she says she's fine and like you doesn't feel tired if she only gets 4-5 hours of sleep.

Interestingly, if she gets the standard number of hours of rest (say, 7-8), she gets really groggy and it totally disrupts her ability to function throughout the day!

Interesting, same here. IF I put whole 7 hours (I cannot 8), I feel tired all day long.

Back when I was trying to make the uberman (and eventually the everyman) sleep schedules work for me, I ran across a person like you, it made me incredibly jealous. He seemed to think it was that his brain only went into REM mode for some reason. As the other comment mentioned maybe it's just a simple gene mutation, if so perhaps CRISPR can replicate the effect... Lots of stuff if you google "Short sleepers".

I hope you use this incredible advantage to do something especially unique for society.

It sounds kind of like an evolutionary advantage. Sleep is probably for multiple uses, but I think most could all be handled in other fashions.

The exception is conservation of energy. Yet, that is no longer relevant in the upper part of society.

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?

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)

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?

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.

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.

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.

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...

Reminds me of the good old days of defragging a Windows hard drive :)

It's more like stop-the-world garbage collection.

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?

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.

Personally, I prefer to miss rush hour on the other side of it ;)

Perhaps they aren't posting on message boards during the workday.

I love being up early but find maintaining an early schedule extremely difficult.

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.

Pretty much useless for me given that my wife rarely it's at home before 7.30 and I'm there before 5..

There a lot of programmers in my company who are in super early and leave by 2-3pm. But I think most of them do it out of necessity because either they have kids or they have long commutes.

If I wake up before 8 for work I feel physically tired. In my current job I'm waking up at 7.30 everyday and I feel that I lost 10-20% of productivity. And it is not strictly correlated with lack of sleep because now I'm sleeping at 10.30-11.30 pm. I can do my best work when I have no mandatory early show in the office and I can arrive whenever I want between 9 to 10, ideally after a nice 30 minutes walk to wake up properly.

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.

I'm an early riser, I do the majority of my work in the mornings.

I like getting up early, where early is defined as 6am to 6:30am.

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?

Title should be updated to reflect 2013.

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

Any sufficiently advanced technology is indistinguishable from magic.



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.

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?

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.

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:


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

> Wait, are there any Neural Nets out there, which produce toxic "weights" to be discarded later

That's what 'dropout' is for ;)

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"

Yeah, all organs produce waste chemicals, the brain is no different in that respect.

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-sc... which links to this Harvard article: http://healthysleep.med.harvard.edu/healthy/matters/benefits...

Well, this article is from October 2013...

Ah, missed that :)

so sleeps are basically GC pauses.

Learned about this few years ago here is the link


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

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

There's a massive difference between using stimulants to be more productive and using stimulants to skip sleep.

Is there?

Obviously. By sleeping enough you get the sleep you need, by not sleeping you obviously don't.

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'.

I take modafinil on a daily basis each morning, and have a regular sleep pattern of 7-8 hours a night.

It even helps with going to sleep earlier, because I feel depleted by 10 PM, so there's less incentive for me to stay up and waste time that I could use resting for the next day.

No more so than caffeine consumers.

Instead of scare tactics you could look at actual costs: https://www.gwern.net/Modafinil#costs


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

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.

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.

Someone who uses a few days a week (not necessarily daily) as opposed to, say, occasional all-nighters before an exam. For example, mrleinad's comment:

> I take modafinil on a daily basis each morning, and have a regular sleep pattern of 7-8 hours a night. It even helps with going to sleep earlier, because I feel depleted by 10 PM, so there's less incentive for me to stay up and waste time that I could use resting for the next day.

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

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

This same article was actually posted here a few years ago, and commented on extensively:




Yes. Certainly a conspiracy.

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