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Researchers identify sleep as a reason why personality traits predict longevity (bps.org.uk)
352 points by laurex 40 days ago | hide | past | web | favorite | 130 comments

I understand this is correlation not causation, but we have tons and tons of evidence for the negative effects of sleep deprivation.

Color me highly skeptical that there are negative effects associated with sleeping 8.5+ hours, up to say, 11 hours. Beyond 11 hours of sleep, I can see an argument being made for physical morbidity from lack of movement etc. But 8-9 hours of sleep nightly - my guess would be that people who get only 7 hours of sleep tend to be more successful, have jobs and families, and access to health care. Whereas those sleeping 10 hours a night are less likely to have the income to get health care when necessary.

In other words, I'd be interested to see studies which test the hypothesis that sleep deprivation has a causal effect on morbidity, while excessive sleep only has a correlation.

Let me reveal some of my personal health for this discussion.

I was diagnosed with minor sleep apnea, and my doctor prescribed an anti-snoring mouthguard (a $1000 device that is basically a mouthguard with a screw in it... ugghhh). Costs aside, the device works, and I've been getting LESS sleep recently.

Why? Because 7ish hours of sleep is all I need now... because I'm not getting minor "self-wakeup events" during night. Before this mouthguard, I needed 9ish hours of sleep to feel rested.

The mouthguard definitely works (for my case anyway. I did some research and its apparently because I've got a large tongue or something, which means my snoring / sleep apnea could be cured by a mouth-guard forcing my jaw into a different position). Apparently, other cases of sleep apnea can only be solved with a CPAP, while still other cases of sleep apnea can be solved with a simple "sleeping backpack" (to prevent sleeping on your back).


Undiagnosed Sleep Apnea is associated with longer sleep, less-restful sleep, and a variety of ailments like obesity and high-blood pressure. I don't think cause-and-effect has been figured out yet (maybe obesity causes sleep apnea, or maybe vice versa).

It is quite possible that excessive sleep is correlated with a variety of sleep-issues, like Sleep Apnea. People who fix their sleeping issues may live longer, higher quality lives.

The _Why We Sleep_ book that everyone's been recommending lately (and I will also add my recommendation) says exactly this. There is no known evidence that anyone has ever been harmed by too much sleep. Rather it seems that people who sleep for an extra long time could have some health problem or sleep issue which causes their body to need more.

I suspect I may have a condition similar to yours. I googled anti-snoring mouth guard and came back with $50-100 solutions, but no "bolt" inside that I could see. What differs between these and yours? Can you give more details eg a brand, a picture, or better description?


The doctor gave me a Somnoguard AP2. I'm not entirely sure why it cost me $1000 from them... but that's what it cost from the doctor. Its clearly cheaper online. Perhaps I should have asked for a prescription from them and ordered online... but its too late now.

I also had a take-home sleep study, consultation fees, etc. etc. on there. I think that maybe I just didn't understand my options as a consumer and I did this suboptimally from a financial point of view.

In any case, the overall industry and regulations DON'T want you to be self-diagnosing things. I think it makes sense to go into a sleep doctor, and first order a take-home sleep study. You pretty much get some weird device hooked up into your nose and a few sensors on your head, and they'll take... some kind of sleep measurements. (Brainwaves? The nose thing probably was recording my breathing patterns, I dunno, I'm not a doctor. They did say a microphone was in the device too, so I guess they're recording the noises I make when I sleep).

I know some people with more extreme conditions may need to do a full-scale sleep study in a specific room. But these are more expensive. Its pretty much a hotel-room, except doctors are measuring all sorts of things while you sleep.

After those measurements, the sleep doctor probably will try and figure out which device is appropriate for you. Its pretty clear that the Somnoguard AP2 can only solve minor sleep apnea issues caused by tongue blocking during sleep: it just shifts the jaw forward by about 3mm to 5mm or so and holds it there during sleep.


In any case, I'm overall happy that I've got my problem fixed. My only regrets is that I'm not really used to interacting with doctors. So I'm pretty sure I could have optimized my gameplan better and possibly negotiated a cheaper bill. But at least I've gained experience... I'll know what to do when my next health issue comes up.


You should buy one like this:


I am sure you can find some in this style for even cheaper, maybe around $20. I had sleep apnea for the last 18 months, which got so bad that I couldn't hold down a job or do much of anything. I would sleep around 14 hours a day, which sounds crazy, but every time I hit REM I would just wake up. So, it would take around 12-14 hours to finally accumulate enough REM to not feel totally fatigued. I would typically wake up around 3pm and just loathe around without much energy waiting for the following night's choking spell.

I tried it all. CPAP, sleeping with tennis balls on my back, a backpack, sleeping face down on a massage table, sleeping upside-down (don't try that). Anyways, for me, the mouthguard I linked was the item which provided the most relief. I went as far as to jury-rig the device into extruding my lower jaw out even further than it was designed to by using some screws to separate the top and bottom even more extensively. It actually gave me a terrible underbite, because at night the pressure from my lower jaw pushed my top teeth back further into my mouth. But, I was able to sort of sleep, and it probably saved my life. Sleep apnea is no joke.

I ended up getting three surgeries, the last of which was just last week and from which I am still recovering. It feels like I am finally cured, and boy, does it feel good to finally sleep.

edit - Oh and if you have any questions please feel free to reach out. I have several lifetime's worth of experience in this area now after working so hard to have this resolved. Email is in my bio.

i wasn’t able to locate your email.

why did you need three surgeries? i had double jaw surgery done and while it improved my jaw, the unresolved issue is my poor TMJ, which the surgeon pointed out. when i sleep on my back, my jaw still falls open and my tongue slides back into my airway.

i am hesitant to use the mouth guard because i don’t want my upper jaw sliding backward. my solution now is to side sleep. help!

Sorry! Try nikk @ getfractals dot com. Changed my bio recently and forgot.

That's pretty insane that you had that surgery; I heard that's one of the most intense treatments they have. Was it specifically for the sleep apnea?

I am very familiar with the jaw falling open/tongue sliding back. I tried a headstrap + mouth taping + mouth guard combo for a while which was often able to keep the jaw in place, but it's finnicky, and sometimes slips, causing the jaw to fall back in deep sleep. Another option I tried were the 'tongue retainers', which pull the tongue forward, but, from the literature I've read, they may or may not prevent the base of the tongue from collapsing backwards. Very subject dependent; I didn't have good results, personally.

Anyways, for my personal case, it turned out that I had enlarged lingual tonsils which were pressing on my epiglottis and causing it to collapse back into my throat. My epiglottis was 'floppy' and collapsed over the airway particularly in REM. The treatment was a lingual tonsillectomy. After that treatment I still didn't feel better and had another endoscopy with a different surgeon which uncovered that my soft palette was collapsing; the treatment for which was this, [0] a treatment which essentially sewed my soft palette down and removed my palatine tonsils.

The whole thing was a nightmare. I'm 5'7 140lbs so maybe 4-5% body fat, in shape, 27 y'o. Outwardly in shape, basically. I'd go to doctors telling them I was not able to achieve refreshing sleep, and they'd tell me I was either depressed or had some psychological disorder. Around four our five dozen doctors told me this. My cries fell completely on deaf ears. To confound things even further, I had four in-lab sleep tests and around 5-6 at-home sleep tests, almost all of which were completely absent of sleep apnea. When pushing for another endoscopy/surgical remedy, one surgeon said, "why would I operate on you? you sleep better than I do." I wanted to cry; so frustrating.

The practitioner that you choose matters; as there are relatively few in the world who understand the complex anatomy of that area and can suggest the particular surgical treatment that's most likely to relieve your symptoms. You'd be surprised to find out that most sleep apnea surgeons provide the same blanket surgery, the UPPP, to all of their patients, independent of the patient's particular problem areas/issues. Not to say UPPP doesn't work for anyone, but, it only addresses correcting a very particular subset of problematic tissues, when the patient may be having collapse in an entirely different part of their airway. The over prescription of the UPPP and most doc's reluctance to attempt to properly diagnose a patient's particular issue is a major reason as to why surgery is often seen as ineffective in sleep apnea treatment and cpap is still the 'golden standard'. I think this will change as cutting-edge research continues to slowly disseminate through the field; but it will probably be a long time before your average sleep surgeon becomes versed in cutting edge techniques.

I am absolutely convinced that Dr Eric Kezirian in Los Angeles saved my life and couldn't recommend him more highly. He has a blog with tons of useful information [1] if you're interested. Even better, I don't think there was a single email I sent him that he didn't respond to within an hour. It's a crazy dichotomy to have an expert surgeon who is also highly available and helpful.

Anyways I hope you find relief.

[0] https://sleep-doctor.com/surgical-treatment-overview/palate-... [1] https://sleep-doctor.com

I have to warn you that I spent a lot of money on one of those and it simply did not work.

CPAP was my salvation.

Glad to see it works for some people, but for me I felt scammed by the doctor that after a while simply said "you should find a way to control your jaw while asleep, it's a mental thing".

The doctors at the sleep center were happy to prescribe the CPAP machine (which their "partner" business supplied), as well as prescribing sleep meds and scheduling regular checkups on me.

Interestingly enough, at the end of my sleep study the technician commented to me that I appeared to have a deviated septum and perhaps I should have that looked at. The doctor who reviewed my study didn't mention that and never suggested I see an ENT for a second opinion.

Instead, I was pitched an implanted device that would ostensibly "cure" the apnea (no thank you!).

I did see an ENT, did get surgery and now sleep soundly. I've never gone back to that sleep center where they were only interested in extracting as much money from me as possible.

The first time I tried a CPAP, it just did not work for me.

Instead I bought a "boil-n-bite" mouthguard off of amazon and it worked great! ... for about 6 months or so.

At that point, I went back and pursued a CPAP and by changing from the over-the-nose headgear to the nasal pillows I finally found something that works for me.

("nasal pillows" - a euphamism if I've ever heard one)

There are the chin guard / mouth guard "Sleep apnea devices" that run about $15 on Amazon most of which are around $2 on Ali express.

I'm guessing theyre not going to work as well as GPs but at $10 for a handful I'll give it a shot.

I'd be wary of putting untested mouth-guards.

Sleep Apnea is literally when you (mildly) choke-yourself while sleeping and can't breath. If the mouth-guard falls off easily and causes a choking hazard, then the mouthguard is worse than the disease.

I know there's online discussion about chin-straps moving the jaw forward. That's closer to something I think I'd be willing to experiment with. I don't see much potential choking hazards or other problems.

At $15 you should try that before forking $1000 (on something that you can get for $150 outside the USA, btw).

Also mouth guard don't cause choking hazard.

I had a dentist prescribed/adjusted MAD which cost $400. I hated that thing. I purchased a $10 nightguard at Target, less intrusive, smaller, more flimsy and flexible version, at target. It works great and last 6 months.

Its not like I'm on Amazon checking prices while the doctor is talking to me. And its not like doctors tell you how much something costs until after they give it to you. These things are mostly "do as the doctor says" and then look at the bill later.

In any case, a lot of the mouthguards are just bruxism / teeth grinding protection. I'll let you know that "pushing the jaw forward" is how my device works.

Other people have linked cheaper stuff from various places online which seem like they push the jaw forward. But most dental-guards I see at Target / CVS / etc. etc. are just bruxism protection, probably not designed for sleep apnea.


Now that I know what I have and can do comparison shopping, the thing that has gotten good reviews seems to be "ZQuiet". Seems to be well reviewed by 3rd party websites, and not super-expensive. $80 or so. https://zquiet.com/

Another person upthread claims they got good results from something from Amazon, but I couldn't find much information about that company or website.

Maybe something like this? https://somnomed.com/en/dentists/somnodent/

I tried a mouth-guard but found it quite uncomfortable. Had one very vivid dream of coughing up a slurry of screws and other fasteners.

CPAP works well for me (when I use it). ADHD -> low conscientiousness -> not always using the CPAP if there's a minor obstacle. E.g. unfolded laundry on the bed can derail me to the couch since I'm usually very tired / low willpower by the time I go to bed.

I've been thinking of a machine vision project: the system yells at me to get up and go to bed if I fall asleep on the couch. Externalize your rationality through cybernetics.

Sleep apnea is also highly associated with obesity, and obesity is not healthy.

Isn't there also an argument that excessive sleep may be caused by health issues that end up affecting longevity as well?

Matt Walker makes this point in his book (at the risk of sounding like a shill). One group of people who sleep abnormally long hours are those suffering from various illnesses - they sleep more either as a result of the illness or while in recovery. Some of them may die. This group potentially skews results and increases the mortality rate of long sleepers. There is no evidence I'm aware of (nor does the book give any) that oversleeping is harmful in itself.

That book is so good that I feel like a shill when I recommend because I recommend it so enthusiastically.

Every single causal link made in epidemiologic studies will have potential confounders that need to be adjusted for. I'd be shocked if anyone could think of a causal link without a potential confounder, never mind that we may have unknown/unmeasured confounders that aren't even top of mind.

This is exactly what I started writing before I saw your post. :)

(Does that make this a discouraged “me too” post…?)

TFA correlates _more_ sleep with increased mortality, but barely speculates on cause, and lumps too much, and not enough sleep together in discussion. With respect to the question of how more sleep might be bad, the article states: "[...]one can speculate that these folk, who have lower moods and more worry, might struggle to get to sleep or to get up promptly in the morning. Lower scores on extraversion were indirectly linked with increased risk of death, thanks to an association with greater daytime feelings of fatigue (perhaps extraverts’ greater daytime activity levels makes it easier for them to get a satisfying night’s sleep, but this is speculation)."

Anecdotally, I think sleep deprivation increases my neuroticsism and decreases my extroversion, so I feel like positive feedback could exist. This makes it harder to do the things that seem to me to improve sleep and mood, like aerobic exercise, exposing oneself to natural light cycles, and other people, and keeping a consistent personal routine. I feel like I have spent periods in a meta-stable state of insomnia after pushing myself too hard because of crunch time, international travel, etc.

I suspect that "excess" sleep may be correlated with chronic health problems like mood disorders (like depression), or auto-immune disorder. These problems are known to be suggestively correlated with each other, and also with sleep problems.

This stuff seems complicated enough to be pretty hard to figure out, and I think you are right to be skeptical about the direction of causality. Pretty sure not sleeping enough is still bad though.

(edit: flow/clarity)

I know that most forms of clinical depression and the treatment associated with it has the side effect of a desire to sleep longer. 10 hours is a normal amount of time sleeping for people on anti-depressants. I'm not entirely certain whether sleeping closer to 8 would be any better for their mental or physical well being.

This reminded me of this article - https://mosaicscience.com/story/staying-awake-surprisingly-e... - which discusses treating depression by purposely putting patients into extremely sleep deprived states.

Note that this is for bipolar sufferers rather than unipolar depression sufferers.

When I finally got medical treatment for severe anxiety the sleepiness side effect from my medication was a godsend. I really think it helped me recover just knowing that no matter how horrible I was feeling, I would be asleep in an hour.

It's worth pointing out that the study cited in the article does use an analysis that looks for causality.

The study says "To formally test mediation [...] calculate indirect effects similar to the Sobel method." I think this refers to a paper "Direct and indirect effects in linear structural equation models" by Michael Sobel. I don't understand enough to say what the limitations are of this method -- but it does sound like rather more advanced causal analysis than you typically see in a medical paper.

I'm guessing that the limitation of the Sobel method is "garbage model in, garbage causal inferences out". It'd be interesting to hear from someone who knows the field, who can say whether the model used in this paper was rich enough to test your ideas (about excess sleep versus insufficient sleep).

Mediation tests don't support causal inference. Sobel method is fine but rarely used now in the social sciences.

Came here to write similar causal / correlation point .

If you currently sleep <7 or >9 hours dont take this as a prescription to change your sleep pattern.

I would assume there is an underlying cause to your sleep needs and that solving the underlying cause is the true path to longevity. For example if you're sleeping more because you're recovering from burnout or a major surgery. Then taking the sleep to speed recovery is (i presume) a better choice than artificially restricting sleep in the name of "longevity" ...

If you currently sleep <7 or >9 hours dont take this as a prescription to change your sleep pattern.

So if you sleep 7, 8 or 9 hours you DO need to take this as a prescription to change your sleep pattern?

That's not logically implied by the parent's statement.

It's also possible that those who sleep 8-9 hours are people who need 10+ hours of sleep but settle for 8-9. Whereas those who sleep 7 hours are those who only need 7 hours.

From everything I've read, it's exceedingly uncommon to need more or less than the range of 7.5-9 hours a night.

As long as you're getting quality sleep, yes. But if you have sleep apnea or another condition that is affecting quality of sleep, greater quantity might be required to feel rested.

Also there's probably an issue with sleep quality. For instance I bet people who sleep deeper require less sleep, not to mention illness and increase sleep requirements.

> But 8-9 hours of sleep nightly - my guess would be that people who get only 7 hours of sleep tend to be more successful, have jobs and families, and access to health care. Whereas those sleeping 10 hours a night are less likely to have the income to get health care when necessary.

I'd hope that such studies on sleep control for income, employment, education and what not.

Also, could the relationship be reversed. They suggest high anxiety -> less sleep -> higher mortality. But it seems possible high anxiety would also directly link to higher mortality (e.g., high blood pressure), and sleep would be a side effect, not the cause of higher mortality. Same with low conscientiousness (exercise less, eat junk food).

If you haven't already, I highly suggest reading the book Why We Sleep by Matthew Walker, a google sleep scientist and director of the Center for Human Sleep at Berkeley. The book is mainly focused on the causal effects of sleep deprivation, but he also mentions excessive sleep.

> my guess would be that people who get only 7 hours of sleep tend to be more successful, have jobs and families, and access to health care. Whereas those sleeping 10 hours a night are less likely to have the income to get health care when necessary.

I think you may be having a selection bias here: there is a lot of people who sleep 8-9 hours at night who are in high income brackets (I think that’s what you mean by “successful”, even though that’s a debatable metric).

The healthcare problem is a US-specific one, although probably if you are in a union job you’re likely to be getting decent healthcare while working hours that let you sleep.

>I think you may be having a selection bias here: there is a lot of people who sleep 8-9 hours at night who are in high income brackets (I think that’s what you mean by “successful”, even though that’s a debatable metric).

I'd disagree. Numerous studies with large sample sizes show the average sleep in America is 6 hours and change. I'd need to see some hard evidence that there are "a lot" of people, that is, a statistically significant number of high-earners, who sleep 8-9 hours.

In fact, there is evidence to the contrary of your claim:

>Turns out, the difference is pretty negligible — the "successful" people get 12 minutes less than the average American. According to this 2013 Gallup poll, the average American gets 6.8 hours of sleep every night.


This may sound like pedantry, but I would call 6.8 "almost seven hours" not "6 hours and change".

I track my sleep as best I can, and nearly-seven is sustainable, while a bit more than six on a consistent basis leaves me feeling pretty wrung out.

The extra 45 minutes we're talking about here are likely to be mostly REM, given how intensely I dream when I start napping to make up a deficit.

> the research showed that too little or too much sleep was associated with increased risk of dying – approximately 65 minutes more than, or under, the average nightly sleep duration (7 hours in this sample) was associated with a 10 per cent increased risk of dying over the course of the study

This seems inaccurate on the high end. Under 6 hours has repeatedly shown to be bad. But over 8 hrs and 5 min? If the average REM sleep cycle is 1.5 hrs, then your only "perfect" window is 7.5 hrs of sleep - 9 would be detrimental?

Other data suggests otherwise:


>If the average REM sleep cycle is 1.5 hrs, then your only "perfect" window is 7.5 hrs of sleep - 9 would be detrimental?

First of all, the hours of sleep measured is not necessarily sleep end to end. It's also getting away to go to the bathroom, lying down a little before getting asleep, etc which can easily eat the extra 30 mins.

And even actual interrupted end to end sleep is not just end to end full REM cycles -- such that it has to divide perfectly to 1.5. Nor are REM cycles all exactly the same, and all exactly 1.5 hours.

A sleep cycle typically progresses N1 -> N2 -> N3 -> N4 -> N3 -> N2 -> REM, before repeating.

The first cycle in a night takes less time--at 70 to 100 minutes--and has the longest N3 and N4, and shortest REM interval. As the sleep progresses, the N3 and N4 phases shorten and REM lengthens, as the overall cycle for 2nd and subsequent cycles extends to 90 to 120 minutes. Later cycles may omit N3 and N4 entirely. The only phases in which you are unlikely to awaken from external stimulus are N3 and N4, so by your last cycle of the night, you are more likely to awaken at any time from an alarm clock or a sunbeam on the face.

It may be that N3 and N4 are used to shut down the body, to perform a physical cleanup of the brain and other organs for their metabolic waste products, and then REM is used to clear out short term memory and compress information from it for storage in long term memory. If so, then the body is essentially reserving the first 160-220 minutes in a night for physical cleanup before allowing a significant REM phase to happen. As REM apparently represents as much or greater brain activity as a waking brain, the NREM phases could then clean up the metabolic waste products from the previous REM phase.

If you take the first 3 phases as a double-NREM, middle cycles as REM-NREM, and the final cycle as REM-wake, your time interval math may work out differently.

I usually feel like I need 9 hours sleep after a good workout. Am I doomed?

Take note that what sleep researchers count as hours of sleep is not the same as what we colloquially count as sleep.

Let's say you get in bed, lights off, at 11 PM and wake up at 7 AM. Most people would call that an eight hour night of sleep. But in reality it takes the average person 20-30 minutes before actually falling into sleep. The average person also wakes up four or more times a night, sometimes for ten minutes or longer. Often we don't even remember all the times we get up. A lot of people also awaken before their scheduled wakeup times, and spend 20+ minutes in pre-dawn twilight.

Add it altogether and an "eight hour night" may actually only constitute 6.5 hours of actual physiological sleep. The only way to know for sure how much sleep you get is to use a device specifically designed for the purpose.

Normally I would be inclined to agree with you but the article specifically says: "The research has some important limitations including ... the subjective measure of sleep being based on time spent in bed rather being asleep per se"

That's exactly what the parent says.

"Add it altogether and an "eight hour night" may actually only constitute 6.5 hours of actual physiological sleep. ".

Which is the problem being raised.

According to the study 9 hrs of sleep is bad for your health (too much sleep). But that 9 hrs may actually constitute 8 hrs of actual physiological sleep. So 8 hrs of actual sleep is too much and is bad?

Fitbit usually logs me awake for around one hour every night, I've adjusted my sleep to account for it and I definitely feel better.

Adjusted how?

I try to be in bed for 9 hours every night which actually logs 8 hours of time asleep. Not always but keeping my weekly average around that amount +/- %5. I'm sure the tracker is off by some amount but it seems fairly accurate.

This right here is why I schedule myself for about 8 hours, but also have my alarm set with a snooze feature of 30 minutes. If I wake up but I don't feel done, I'll allow myself to snooze a few times before actually getting up.

It's simple, but surprisingly effective. I figure, all the studies in the world are nice, but listening to the signals my body gives me is probably the best approach. 30 minutes is about the length of one more REM cycle, and I tend to find that I dream most vividly during those snooze sessions, and wake up remarkably refreshed by the end of them.

Have you tried it the other way round... set the alarm those 30m later but if you wake up earlier, just get up?

Do you have any specific devices in mind?

I've used (a) the Beddit touch-sensitive mat, (b) the Fitbit watch, and (c) the Oura ring. Beddit claimed I never slept more than 2 hours a night, which was something of an exaggeration. Fitbit was better, but I still caught it a couple of times claiming that I was asleep when I was actually lying awake reading for an hour. I've been using the Oura ring for maybe 6 months and I haven't caught it in any known mistakes so far; there was one weird thing where if you had multiple sleep periods separated by several hours, it'd show only one of them in the cloud view, but I've not hit that recently.

I would recommend the Oura ring with few reservations.

I have a Xiaomi fitness band 2. As far as I can tell, the sleep metrics it reports are pretty good. I wouldn't attempt to compare its accuracy to an Apple watch, but the Xiaomi's battery charge lasts about a week and it cost $30.

I'm really impressed with Mi Band 2 sleep tracking. It correctly matches the time I go to bed, and get up. Also gets each time I wake up during the night, or when I'm reading before sleep. I'm not sure about the "deep sleep" recording, and maybe I'm being suggested, but in nights with low deep sleep I fell terrible. Just monitoring my sleep I improved it. Sorry that it does not have a smart alarm neither an alarm to go to bed.

Withings (ex Nokia) is selling mats that you put under your sheets and where you lie on. I think Apple does, too, but only in America.

That's probably the best device for home-use. But sleep labs are using EEGs, cameras, microphones and puls oxymeters for a reason. Don't expect medical-grade results from a home-use device.

Less accurate are several kinds of fitness trackers/smart watches, very inaccurate are smartphone apps.

I wish the Withings mat would have the option to wake me up when optimal time comes. I had a fitness tracker that did that but it was very subtle and started working after a few weeks.

Are you thinking of the Pebble watch? Maybe in combination with some Android app? I had this setup years ago and I do miss it. I'll have to see whether it can be replicated with my current Fitbit, last I checked it couldn't but it was a while ago.

I don't know what specific devices they may have had in mind, but one accessible way to track sleep is with a smartwatch.

I use a Huawei Watch 2, and it tracks pretty accurately from what I've seen. Other Wear OS devices are probably similar.

I personally find the Oura ring to be great at tracking sleep stages and various biometrics during sleep like HRV and body temp change.

But there's no way whatsoever to use to wake up at an optimal time, right?

I have a Luna smart mattress topper. I think they rebranded to Eight or something. Pretty good stuff.

Yup, your risk of eventual death is about 100%

I know it's anecdotal but so far I haven't died.

I used to need 9 hours after a workout, but that doesn't seem to be the case anymore after three years of weightlifting. Perhaps because I now know which exercises are bad for me. Or perhaps because I'm more careful while performing the exercises.

Disclaimer: Not an expert.

When you do a hard workout for the first few times, there are a lot of neural adaptations. These result in very quick gains of strength within the first few weeks, I think mostly due to better muscle recruitment. At the same time, these neural adaptations are taxing on the brain/CNS. This is especially true of exercises that require intramuscular coordination. In my personal experience it makes it very hard to fall asleep when I learn a new, complex power exercise (e.g. campusing [1]). It also seems logical that you need more sleep for those neural adaptations to take place.

Now, once you are experienced in the exercise, there are much less neural adaptations, hence the perceived plateau in strength gains. The way you make gains now, is mostly through muscle growth (hypertrophy) which takes much longer but doesn't tax the CNS as much. This might explain your observation of needing less sleep after intense workouts, now that you have more experience in your sport. Try a new intense exercise and you will likely experience the above described process again. Just don't injure yourself!

[1] https://www.youtube.com/watch?v=7ACyeOP-Hxo&t=5m40s

Isn't it also because participants of these studies who sleep too much does so because they already have health problems that keeps them in bed?

Well, it's morbid, but we're all doomed.

It's correlational, not causal. People with health issues are a disproportionally represented among people who sleep a lot.

I've always been interested in the direction of causation behind the claim "too little sleep is correlated with an increased rate of death". People talk about it like it's proven that lack of sleep causes death, but is it just that many health issues cause you to sleep more/less than average?

Applying that line of thought to the article, if you have a health issue that is causing you to lose sleep (e.g. due to pain or hormonal issues), is it unreasonable to think that might increase your neuroticism or decrease your extraversion?

I've no idea if anyone has ever managed to determine the direction of causation here, seems like these longitudinal studies don't have the ability to disambiguate.

If you're really interested, read the book Why We Sleep by Matthew Walker. The book references a ton of studies that show, definitively, getting less than 7 hours of sleep is hugely detrimental to your health.

The book actually talks about how psychiatric disorders cause insomnia which creates a feedback loop of getting less sleep, which amplifies the detrimental effects of the disorder, which in turn worsens the insomnia.

It does not show that at all, especially not "definitively". Matt Walker's career is based on fearmongering about sleep. The actual studies are quite mixed. Here's a recent one that showed little to no effect of short or long sleep lengths on cancer risk: https://www.ncbi.nlm.nih.gov/pubmed/30463535.

Feel free to read the book, but don't do so without strong skepticism. In particular, the book never actually attempts to answer the question in its title, other than to present some vague, unfalsifiable theories. It presents tons of information, but no answer to the question.

There were parts of the book that I was definitely skeptical of, and after doing some research, found were not supported by any studies that I could find. So I will agree that you should remain skeptical about some claims... Really, you should be skeptical of anything you hear.

But the fact that under sleeping has serious detrimental effects on your health is supported by many studies.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2845795/ https://www.ncbi.nlm.nih.gov/pubmed/8621064 https://jamanetwork.com/journals/jamainternalmedicine/fullar... https://jamanetwork.com/journals/jamainternalmedicine/fullar... https://www.ncbi.nlm.nih.gov/pubmed/19109114 https://jamanetwork.com/journals/jamainternalmedicine/fullar... https://www.ncbi.nlm.nih.gov/pubmed/6878979 https://www.ahajournals.org/doi/full/10.1161/01.HYP.00002173...

There are so many studies out there about this, I don't see how you can deny this fact.

It's on my list, this will bump it up. Thanks!

Off the top of your head is there similar data on getting too much sleep? It makes a lot of sense that (past a certain point) lack of sleep could be harmful, since going without sleep is eventually fatal. However this could easily be compatible with too much sleep being harmless.

From what I've read, yes, there are similar risks associated with getting too much sleep. But don't take it from me, I'm just an engineer that recently became interested in the topic. If you search Google Scholar, you will find a ton of studies that will help answer your question.

Also, like the poster above pointed out, there are parts of the book that aren't really supported by studies, at least not studies that I could find. Make sure you do your own research before accepting anything as fact.

The most useful aspect of the book to me was just emphasizing how important sleep is to all organisms. There's a reason we've evolved to spend a third of our existence sleeping.

Also the fact that as we age we gradually lose the ability to sleep...

Seconded. He points to a ton of consequences of short sleep. Cancer being one of them.

I can't imagine that all that stress to min/max health outcomes through strict behavior changes is good for you or worth it in the long run.

I subscribe to some nutrition and fitness subreddits and I see people obsessing about minute details of what they eat, how much they sleep, obsessing to take control over every facet of their lives because of some study they read on the internet.

I contend that worrying about these things is counter productive. Of course you should get enough sleep, you should exercise regularly and generally eat healthy. Check with your doctor, but this will probably be enough to avoid life style inflicted harm long term.

Strict controls and obsessive attention to your everyday life to maybe postpone death by some unknown amount of time, probably not worth it. Death sucks, but it's inevitable and no amount of finessing health choices will change that.

I agree. Sacrificing your mental health for your physical health is counterproductive to the goal of whole well-being. Obsession is harmful. Moderation is key.

While I agree, unfortunately sleep when you're tired and eat when you're hungry doesn't exactly apply well to the modern first world

Easy to say when you are healthy. Some folks have more to worry about than others.

I have a habit of going down this rabbit hole. I always rebalance myself by asking, "Am I Bruce Wayne?" If the answer remains 'no' than this doesn't require as much thought as I'm currently giving it

Based on my experience, I can say that after very difficult strength workout like rings, 1 arm pullups, iron cross, etc., there is a huge difference in recovery on the days that I sleep 11 hours vs. the days that I sleep 8 hours only.

On the other hand, sleeping less than 8 hours a day is devastating (check the book 'Why We Sleep' for details)

Moreover, I've read that this was known among 19th century strongmen (Eugene Sandow slept 11+ hours a day).

So whatever happens during sleep, we need more of it (if we stress our body more).

I highly doubt that in itself (sleeping more) is detrimental in any way.

I have also seen similar recovery benefits from longer (11+) hours sleeps. During a period of a few months I worked out heavily every day, and noticed better recovery and faster strength gains from the longer sleeps. One downside with the longer sleeps was that I would not get tired at the same time each night, so my sleep window moved later and later until I needed to skip a night's sleep to reset, so I was probably sleeping more than my normal rhythms required

I'm half-convinced my gains all come from afternoon naps after large protein-rich meals the day after training.

Might be an age thing but I'm seldom able to stay in bed for more than seven, eight hours at most. Fortunate to have a lifestyle that supports taking naps a few times a week.

Maybe "the indirect link between higher trait agreeableness and risk of dying" is due to others in their environment keeping them up and they going along with it even when they are tired.

I saw this with a partner. She was extremely agreeable and would compromise her own sleep to make time for others. I suppose that doing this over time adds up and extracts a toll.

I always sleep like a baby on weed, that must mean I will live forever (yeeey).

On the other hand, tomorrow I often feel tired throughout a day, even more then as if I slept 4-5 hours without a weed, which might mean I should start looking for a parcel (meh).

This study just gave me cognitive dissonance.

According to some videos in which Matthew Walker (the author of "Why we sleep") is answering some Q&As on the Internet, he briefly talks about weed and alcohol.

Both these drugs are used as sedatives, but they are not good for your sleep. Your sleep cycles are just not the same (e.g. you don't get to REM as much) and it is considered detrimental for your sleep.

As others have mentioned in this thread, I highly recommend reading "Why we sleep" by M. Walker. It's one of the best books I've read.

Weed withdrawal causes insomnia, especially in heavy/daily users. If you want to see how much sleep you actually get without being on weed, you should take an 8-week break first.

I recently took an 8 week break and I noticed sleep returning to "normal" after about 1-2 weeks. I had a couple nightmares while in REM rebound though which really sucked and never happens to me otherwise

My experience too. Around second week insomnia is away but dreams return... often not in a good way.

I think there's some studies that have found that THC may reduce REM sleep. So while you're sleeping more easily, you're getting less "restful" sleep than you would sober.

I find that people tend to believe there is a specific amount of time, or even range of time that is ideal. The body is massively complex and ideal sleep time is completely different on a person to person basis. You must understand that there is no ideal sleep for you that a study will be able to identify, you need to test your own hypotheses and decide for yourself.

For anyone with sever deviated septum who has trouble sleeping because they can't breath through their nose which often causes excessive dry mouth, I highly recommend trying [1] Nose Vents.

Since using them I get much better sleep, don't wake up with dry mouth and a need to drink water all night. It only takes a few nights to get used to them. I use the largest silicone pair, despite the fact that it seems like its a tad to large, because it widens the nostril to ease breathing. Your mileage may vary.

[1] https://www.amazon.com/gp/product/B0743KZK88/

Thanks for the suggestion. I'd like to add that I use Breathe Right strips and they seem to help a lot.

It all seems to come down to sleep when looking at lifespan. Despite knowing about all the risks from not sleeping enough I still struggle to want to sleep a full 7 hours.

And as the article mentions I do see those links in my personality associated with people getting a lack of sleep.

I'm a natural night owl, and I love being awake while most people around me are asleep. However, with "normal" life/jobs, that is a recipe for chronic under-sleep.

However, once I started working for myself, following my own schedule, I found it quite easy to get 7-8 hours of sleep per "night". I go to sleep when I want, and I usually wake up when my body wakes me up. I almost never feel tired anymore.

So in my opinion, the problem is the forced schedule most people have to suffer.

I have the same kind of problem, I much prefer the nights, but am constrained by the "normal" job schedules. Also to compound the problem I do a side medical job at events which typically happen at late evening/night or on the other side sometimes start early in the day. It makes it hard to maintain a regular schedule.

Article gave a harsh summary, then you go to the study and they give you an abstract that explains almost nothing more without a pay wall. I would rather have the data be free, and everything else pay. There's no way to know if this is a bad study without giving them money.

>Lower conscientiousness predicted increased death risk via the direct, indirect, and total effect of quadratic sleep duration. Although there were no other direct personality-mortality effects, higher neuroticism and agreeableness and lower conscientiousness predicted increased death risk via the joint indirect effects of quadratic sleep duration and higher daytime dysfunction.

> nothing more without a pay wall

As (almost) always, you can find the full article in Sci-Hub. It's not 2010 anymore.

Can someone be genetically blessed with not requiring 8hrs sleep?

How much sleep do we need and why?

A friend of mine is a security researcher and he has been awake for one entire week by napping barely 10min for the full week

You can be genetically blessed. The "gene variant ‘p.Tyr362His’" let's one get by on less than 5 hrs of sleep. See: Margaret Thatcher. A friend of mine that got 2 Bachelors and 2 Masters degrees in 4 years might've had that, though he said he just got used to the lack of sleep.

source: https://www.telegraph.co.uk/news/science/science-news/110061...

If I recall correctly, the odds of you having that gene variant are somewhere in the realm of getting struck by lightning.

Also, Margaret Thatcher went on to develop Alzheimers.


Its kind of amazing to me that we haven't heard more, or maybe aren't seeing more, research into drugs or therapy which could reduce the amount of sleep people need. We'd be talking about the greatest boon to global productivity in the history of mankind, likely singularly more impactful than any other technology we've ever developed. The company which develops it could sell it for literally any price and they'd have people scrambling for it.

Not suggesting its easy, or possible, but its just surprising to me that I don't hear anyone talking about it. Modafinil might be the closest I've seen but its obviously not for long-term use. Google/Alphabet is pouring hundreds of millions into Calico to fight aging, but fighting Sleep feels like a much easier target that could have much more impactful consequences (extending life from 80 to 100 isn't nearly as interesting as giving a ~30 year old even 10% more time with their younger body and mind).

And once its solved we'll inevitably flip into a dystopian society where the poor either can't afford the drug and thus become poorer, or are the only ones taking it because they now have to work 22 hours a day, but Hey, we'll worry about that when we get there.

Why do you say modafinil is not for long-term use? I take it 7 times a week, have done so for years and my doctor tells me it's likely that I will be taking it as long as I need it (in my case: a lifetime, as it's treating a chronic condition).

There is a tiny fraction of the population that has a certain gene that allows them to get by on less sleep[0], but definitely not 10 min for an entire week.

[0] https://www.ucsf.edu/news/2018/03/410051/scientists-discover...

Yes, but apparently it's very rare. You are much more likely to have some other issue to blame for your lack of sleep, rather than being genetically "gifted".

There is no absolute "gift" anyways

It's always a trade off, that's what I felt till now

This was on just few days back


Check out the HN comments.

I wonder whether the link between sleeping less and eating more (or for longer hours) has been studied.

What if you sleep only five hours but restrict eating to the same hours as someone sleeping seven hours?

If sleeping is about giving the body a break, it seems pretty obvious that not eating would be a major part of that.

In other words, the wages of hustle are death.

since everyone is so hot on correlation and causation in this thread: i've seen some nice looking charts of all(?) the ways causation might work between two variables that are correlated. they have maybe 14-16 nice little directed graphs to them.

anyone happen to remember/recognize what i'm describing and have a link to it?

I don't think this is what you are looking for, but, it put me in mind of the book Spurious Correlation that shows how easy it is for things to seem related:


Ok, so if I’m anxious or depressed but I sleep the optimal number of hours, I’ll maximize longevity anyway?

I suppose it depends on the quality of sleep. AFAIK, anxiety and depression reduce quality sleep time, which reciprocates itself into worsening anxiety and depression.

Undiagnosed issues that cause the depression and anxiety in the first place often also cause sleep issues (thinking food intolerances and underlying inflammation), so it's hard to extract data to separate the two symptoms.

Summary: 7 hours of sleep is ideal; +/- 1 hour of sleep is related to increased risk of death.

Everything else in the article seemed to be a lot of assumption and guessing about why people got more or less sleep.

Perhaps the article poorly represented the content of the study...

According to a military study referenced by William Dement https://www.youtube.com/watch?v=8hAw1z8GdE8?t=29m it is 8h:15m +- 50min

I like this number better :). 7h is ok for me, but 8 feels so much better.

Anecdotally, I used to feel extremely tired all the time, which I remedied by trying to get more sleep than the average...usually between 8 and 9 hours. I still felt tired.

However, since being diagnosed with sleep apnea and treated via CPAP, I physically can't sleep longer than 7.

True, if your "sleep" time isn't actually rest, it doesn't count as sleep. Sleep apnea, as well as other sources of disruption, prevent one from getting the natural complete deep sleep cycles.

I think a lot of people don't realize when they have something like this... it's usually a partner who finally complains.

I wonder if too much or too little sleep as a symptom of illness was taken into account here? It doesn't seem like the article addresses that question.

i'm wondering if midday napping was factored in

A fitting username lol

I hope your's isn't.

Garbage in garbage out. Their data is worthless

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