How can people even take this kind of pseudo-science seriously?

If I sleep for 5 hrs, I'm a complete zombie during the day, unproductive and depressed.

If I sleep for 8.5 hrs (which is how long I sleep naturally), I feel great, productive, and happy. I get way more done.

There are all sorts of studies showing all the negative effects of not getting enough sleep -- that sleep-deprived doctors, for instance, are basically acting under an impairment equal to a few drinks of alcohol.

The idea that people in general are getting too much sleep is really quite preposterous.

Your rebuttal of this "pseudo science" is that you perceive that you personally need 8.5 hours sleep - now that smacks of pseudo science to me.

People are very different. Just because 1 person in a 1000 (or 100 or million or whatever) benefits from 8.5 hours sleep does not necessarily mean that in general one might get more benefit from less than 8.5 hours sleep.

This is not hard science, I doubt it could ever be, but that does not mean it is pseudo science and certainly should not be dismissed out of hand because it does not fit into the model of the world that you have personally.

> people who sleep between 6.5 hr. and 7.5 hr. a night, live the longest, are happier and most productive

O RLY? Time for another basic primer on causation vs. correlation.

Note that I am not saying that the result is fact, just that there is science to indicate that things are not as simple as they may appear to people that dismiss the whole thing as "pseudo science".

I'm afraid "science" is quite a bit more complicated than you seem to believe.

One of its most basic tenets is that extraordinary claims require extraordinary evidence. One study is not enough to prove the assertion that people who sleep for 6.5 to 7.5 hours a night are the happiest.

It is not at all something I can experiment with directly, unless you believe that sleep under the effects of sleep-inducing drugs is equivalent to natural sleep (it isn't, in my experience).

You can't really lengthen your natural sleep cycle without conflating things with drugs, but I've found that personally I can sleep up to 11 hours if I let myself (although there may be another conflating factor as I tend to sleep more when I'm learning something hard).

"The sleep deprived person can in fact deliver the exact same results as someone who isn’t sleep deprived in any exercise. That is, given it is a non repeated exercise and they give it their best shot."

This phenomenon is called neuron tiring and he makes it sound like someone only carries out wrong judgements sparingly whereas it is more like when person is exhausted from running. The person's legs don't turn off, they are tired. They are still useable and could probably sprint for a very short distance but will eventually start shaking. If the person tries to sprint again, he can but still not for long. This is what being tired or sleep deprived does. You can go for very short sprints but you fail at endurance.

And the 8 hours thing is a mean and it is not pseudo science. Google actual medical sources and see for yourself.

On another note, even when we're talking about mortality, I don't think that sleeping 8.5 hours might be worse than 5. That seems to be an off-hand remark during the interview, to me.

[1] I don't recall any study looking specifically at task performance after oversleeping. The link to the study in the OP's post (http://www.sfn.org/index.aspx?pagename=news_052008&print...) is broken. [2] http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2869.2008....

What perplexes me is this notion that a person's optimum amount of sleep stays constant whatever they're doing (confounding factors like alcohol, illness and recent sleep-deprivation aside). Surely I'm not the only person in the world whose sleep requirement varies considerably according to the level of physical and mental exertion of the day before, climate, diet, ambient stress level etc.?

And whilst I believe naps probably are a good idea, I'm a bit perplexed to how one times a nap so it ends up being at least 20 mins and no more than 30 mins. Often it takes me that long simply to fall asleep, especially if it's a sunny mid-afternoon and I have plans for the rest of the day to be thinking about...

My own experiences seem to fall in line, but it may just be a placebo effect.

If I sleep for 5 hrs, I'm completely fine. I can do that for days on end. If I sleep for 9 hrs, I'm completely fine as well.

The reality, and from what I've read by cognitive scientists (there are a few), there is no set number of hours of sleep a person needs. For the right person 5 hours is great. For others it isn't. Which is a whole lot better than the crap "common wisdom" of EVERYONE NEED 8 HOURS OF SLEEP that is thrown out for days on end.

Also, never take personal anecdote seriously. Anecdotes will only lead to worse science, not better.

If I sleep 9 to 10 hours, I do feel groggy/sleepy for several hours—it's not pleasant, but mellow grogginess/sleepiness is wonderful compared to the demoralizing mental and physical exhaustion I feel when I've not slept enough.

The best answer is probably something along the lines of when you're tired, sleep. When you're sleeping, sleep. If you have some weird imbalance leading to poor sleep, talk to a dr. This philosophy of life also works pretty well for drinking glasses of water, getting laid, and probably about 80 bazillion other human activities.

Furthermore, some people are curious about their body, and wish to understand better activities which consume about a third of their lifetime. I'm one of those people, and even if I get literally no useful information out of reading an article such as this, I am still happy to have read it and to have thought about it, simply because it satiates my desire to learn more about myself.

I have lived in a country (Taiwan) where a siesta, a mid-day nap, is quite a regular practice. The first time I lived there (1982-1985), I was only unlearning my American habit of sleeping only at night near the end of my stay. The second time I lived there (1998-2001), I was better able to adapt to napping in the middle of the day like my co-workers, perhaps because I had become a care-giving parent of young children in the meanwhile.

As the submitted blog post mentions, there is a research basis for thinking that symptoms of what is characterized as "lack of executive function" or "ADD" can be relieved just by getting sufficient sleep. It appears that one of the roles of sleep is letting the brain have opportunity to restructure based on new experiences while awake, so sleep seems to aid learning, planning, and attention control.

I had a friend back in my college days who was a very hard-working research scientist trying to find a cure for diabetes. Her claim, which she read somewhere back in the 1970s, was that an hour of sleep before midnight is just about as beneficial as two hours of sleep after midnight. It does seem to me that I wake up especially rested on the rare occasions when I am fully asleep for the night before 11:00pm. As my own lifestyle changes over the next decade (= as my children grow up and live on their own), I will be eager to try the experiment of better matching my hours of sleep with the actual hours of darkness in my time zone.

AFTER EDIT: The top level comment by rayiner mentions allergies and writes

I jack up a humidifier

and I agree with his statement that it is worthwhile to figure out what helps sleep be deeper and less disturbed, including breathing without obstruction during sleep. Depending on what a person is allergic to, DE-humidifying may be the way to go. Dust mite allergies, for example, will be worse for a person who lives in a humid room. Good luck to all in your experiments.

If you're a person who reads the description of ADD and says that it sounds like you, maybe a lot.

If you're a person who has the disorder, sufficient sleep is not going to make it go away.

IIRC, the "disorder" is mostly a psychological thing, not something concrete.

And it's uptick can also be ascribed to the willingness of more doctors to diagnose something where there was nothing before (to assist in selling some drugs, among other things).

So the two situations you describe here are not at all contradictory.

Dismissing a genetically transmitted brain chemistry problem as "mostly a psychological thing" is extremely unhelpful.

You can't have one without the other, perhaps .. perhaps, the reason we have the genetic scenario now, is precisely because lack-of-sleep, or at least sleep-culture-effecting-brains, has been an environmental factor over the period of our evolution where such things mattered.

I think the entire point is, if sleep helps you focus, then for goodness sake: get the proper amount of sleep.

Sleep is good. Get sleep. But people who actually have ADHD do not simply lack sleep. End. Of. Story.

Your speculation of lack-of-sleep being the cause of ADHD is laughably wrong. If it were true, then my son wouldn't have the disorder.

But I would say to you this: there are other ways to deal with your problems than to form a dependency with a pharmaceutical company and a consumer-dependent relationship on other high preists of industrialized medicine. I know you won't accept that, given your position on the matter is pretty clear that of one who has succumbed to the problem, but the point of view that ADHD diagnoses and treatment is overly exagerated is an equally valid one.

Your son has a 'disorder' described to you by your high priests. However, maybe he just needs a better way of life, a healthier diet, more interaction, more outside time, less participation in a caustic, chemical society. You wouldn't know that, unless you tried to exceed the imposition of cultural 'normality' imposed on you by your society, by, frankly, leaving it behind.

You have absolutely no idea of how much of an asshole you are being right now. You have your opinion, absolutely no facts about my personal situation, are making a ton of assumptions, and yet think that YOU have the right to lecture ME on this subject.

For the record, my son gets a much healthier diet than is standard in our society. He gets several hours outside every day. We have never had a working TV in his life. As he has grown we have allowed him movies - typically under 4 hours per week. He goes for regular hikes. Yes, we use medicine, but only the minimum necessary to affect his ability to pay attention in school hours.

When he is not on medication, the following sequence is common. I can address him by name, he looks at me, and I tell him to put his socks and shoes on. This repeats 3x at 2 minute intervals. His socks and shoes remain not on, and when I ask him to tell me what I've been asking him to do he honestly doesn't know that I want him to put on socks and shoes. Not because he's malicious, but because he simply was lost in his thoughts.

Yes, that is a culture-specific requirement. But if he was being raised in a "natural hunting/gathering society" he'd be the kid who gets eaten by a tiger because he was too busy looking at a spider to watch out.

Now you may think that there isn't a problem here. But I'm the parent here, you're the stranger, you know nothing about my situation, and it is my job to decide what measures are required to make sure that he grows up to be able to survive in society to my satisfaction. So, in all honesty, it is time for you to fuck off.

Every guess you've made since about how my family resembles your stereotype of a family that would medicate has been laughably wrong. I don't know what you think you know, or why you think you know it, but you've demonstrated a complete inability to acknowledge any experiential input. In light of that grotesque failure, I suggest that you question your own firmly held opinions. Because so far you're batting 0.

Here is another mistake of yours: if I was medicating my son for my sake, I'd medicate him every day, rather than arranging for him to be under the influence of medication only for the periods that he's in the classroom. In fact the main benefit that I have received so far is that I no longer have to comfort him while he's crying about how frustrating school was for him.

I hope for your children's sake that they never require assistance that you're unwilling to consider for them. Luckily most don't, so their odds are pretty good. But I'm sure that if you get the average result, you'll take all of the credit for them doing expectedly well.

You continue striking out. I'm an atheist.

But you seem to be the kind of atheist that gives the rest of us a bad name.

I didn't say it's entirely made up. Some people might legitimately have it. But I'm pretty sure from what I've read that a large majority of them do not. To quote Wikipedia:

"""In the United Kingdom, diagnosis is based on quite a narrow set of symptoms, and about 0.5–1% of children are thought to have attention or hyperactivity problems. The United States used a much broader definition of the term ADHD. As a result, up to 10% of children in the U.S. were described as having ADHD."""

I read those numbers, knowing how the medical "industry" works -- and how societal, work/life balance, dietary and other such issues in the US are fast to be characterized as "diseases" in need of medication -- with huge grains of salt.

100% more cases in the US? Sounds like a good deal of over-diagnosing the non existent to me.

No. "Over diagnosed" simply means that it is diagnosed when it shouldn't be. There is nothing there about how frequently it is correctly diagnosed. If the true prevalence is 6% and 9% of kids are given the diagnosis, then it is over-diagnosed. See http://www.cdc.gov/ncbddd/adhd/prevalence.html for the geographic variation on the diagnosis rate. Clearly there are places where it is over-diagnosed. There are others where it doesn't seem to be.

I do not know why the ICD-10 has different criteria. The US classification is broader on that because a much wider variety of symptoms looks the same in brain scans, and reacts the same way to medication.

Regardless, before medication parent-teacher conferences were elaborations on the theme that my son required more attention than the rest of the class combined, and yet still was behind everyone else on a long list of things (starting with handwriting skills) despite his obvious brilliance. After medication we simply get a note that he is a joy in the classroom, and she wishes that other kids had half of his curiosity.

Note, he gets plenty of sleep, eats well, has carefully controlled TV, etc. (My definition of carefully controlled = no TV, under 4 hours/week of movies. The movies that he chooses are documentaries more often than not.)

I feel this unfairly divides ADD between "people who think they have" and "people who have" but in my experience this is a horrible line to draw.

Many doctors will listen for a stock phrase and hand out a one page questionnaire and diagnose you with adult on-set ADD on the spot.

Bam, then you "have" it, doctor verified and everything.

And yet, that person who "has" it may be no different than the one who read what is basically the same questionnaire online.

All doctors, from radiologists to orthopedic surgeons, are told not to self-diagnose, and psychiatric conditions are the easiest to improperly self-diagnose, even for trained professionals (which most people on HN are not).

On top of that, ADHD is one of the most difficult conditions to properly diagnose. Unlike more overt disorders, like schizophrenia, the symptoms are less clear-cut, and unlike more visible disorders, like (true) OCD[0], the symptoms usually lie two or three layers deep, making it easy to confuse the cause of the symptoms if you're not careful.

There exist differential diagnoses for this purpose (disambiguating the cause of the symptoms); most people just don't have them done, because they're incredibly expensive (several thousands of dollars), as they're very time-intensive on the part of the doctor.

That said, the entire claim which precipitated this discussion - that ADHD is somehow related to sleep deprivation - is completely preposterous. ADHD is perhaps inappropriately named, yes, but that suggestion is like saying that the cure to depression is to "stop being sad".

[0] I say "true" to distinguish clinical obsessive-compulsive disorder from the casual use of the term (eg, "oh man, my OCD kicked in when I saw Comic Sans mixed with Papyrus").

There's quite a bit of research on the subject, and researchers don't generally consider a relationship preposterous. It's reasonably well established that sleep disturbances and sleep deprivation can at least exacerbate the symptoms of ADHD. Some research suggests that they may also be a risk factor for developing the condition in some cases, or alternately (depending on unresolved questions about etiology) that a differential diagnosis is needed to distinguish non-sleep-related ADHD from symptoms related to sleep disorders. The diagnoses do empirically seem to co-occur quite frequently, which is one factor driving the research, but the mechanisms aren't well understood.

Nature published a short review of the (very large) literature on the subject last year: J. Cassof et al., Sleep patterns and the risk for ADHD: a review, Nature 2012(4): 73-80.

It calls into question, somewhat, whether there actually are any valid diagnoses, if a disease is well-known to be very commonly diagnosed improperly.

However if a random person claims to have it, we may not be confident that they were correctly labeled.

Many things can cause distractibility, from sleep deprivation to thyroid disorders. ADD/ADHD is only one of them. The effective treatment for any of these will not help the others. That is why the DSM-IV includes as a diagnostic criteria that you have to screen for other possible causes of the behavioral issues and rule them out.

The "many doctors" that you describe are simply not doing their job properly. By comparison the screening process for my son's diagnosis took about a month. Possibly not coincidentally I live in California - a state that has one of the lowest rates of diagnosis of ADD and ADHD. (Look at http://www.cdc.gov/ncbddd/adhd/prevalence.html to see your state diagnosis rate - I'd be suspicious of any diagnosis made in Alabama.) I am confident that my son's diagnosis is correct - my son has responded well to medication, while children without the disorder don't.

So here is my point again. If you're noticeably distractible and possibly sleep deprived, try getting more sleep. It might make a big difference. If you've actually got ADHD or ADD it won't hurt you, but it won't fix the problem either. There are other things that can also produce the same symptoms. Go to a competent doctor if you've got reason to be concerned.

This isn't entirely true. A person that isn't getting enough sleep can "fix" the problem with ADD medications, and thus maintain the erroneous belief that they have ADD and therefore require that medication. How often that happens is debatable, but it is one of the (many) things that lead to over-diagnosis.

And since a side-effect of the medication is trouble sleeping, I could see a vicious cycle starting.

That is not a valid way to test that people are sleep deprived. Most people will fall asleep with plenty of sleep. Put them in a warm room with little noise and nothing to keep their attention and they'll fall right asleep no matter how much sleep they've previously had.

In any case, just want to reaffirm that the test proposed in the top comment is way off target.

1) Sleeping in multiples of 90 minutes really does work. It takes me very little time to fall asleep, so I can pretty predictably set my alarm to wake myself up in-between sleep cycles. My baby likes to sleep in three hour increments, and with two of those I feel great in the morning, even though I wake up in the middle to feed her.

2) Establishing a comfortable sleep environment. I jack up a humidifier and put on a Breathe-Right strip. I have low-grade allergies half the year and while I can breathe without one, I find myself feeling much more refreshed in the morning when I sleep with one on.

Most of all, sleep is something worth experimenting with. People spend huge amounts of their time sleeping, and sleepiness has a tremendous impact on productivity, but I find that most people don't introspect much with regards to their sleep. Going from not sleeping well to sleeping well is the ultimate life hack in my opinion.

Yep.

Through experimentation, I've become a believer in ritual to prepare for and wake from bed as well as napping.

My sweet spot seems to be 8 hour sleep with a 40 minute nap round 13:00. If I had to choose, I'd take less sleep overnight before losing the midday nap.

Prior to experimenting, I was "sure" I functioned optimally at about 6 hours per night. Looking back, I expect it wasn't the specific duration that helped, just consistency.

Also, I second the breathe-right strip.

S/he talks a lot about the 90 minute cycles on babies, we used it on our child and its amazing how well it matches.

And yes, as a parent, those 90 minutes cycle naps with your kid are amazing :)

Since I gave up carbohydrates, I haven't had that hypoglycaemic productivity dip at a predictable time after lunch. As a contractor, I've sat in different offices and witnessed those around me experience 'the dip', whereas I can now soldier on through the day from morning to evening with consistent alertness and focus levels. Oh, and creatine supplementation helped a lot, too.

Another useful trick is to buy a blackout blind or window cover. I've managed to make my bedroom pitch black from the beginning to the end of my sleep cycle, and I know that my sleep is much better for it. It goes without saying that if the sun rises early where you live, and you happen to go to sleep late one night, it can be impossible to get the full 8 hours you want if the light starts streaming in before you've finished.

+1 to this suggestion. I sleep far better, and am much happier, if I have the ability to properly black out the windows of my bedroom. It's not just the obvious stopping the sun shining in in the morning - it's the second order effects too, like removing the anxiety of not being able to fall asleep before the sun comes up. It makes a big difference, in my opinion.

Then I went on a year long vacation - and after the first couple months of sleeping over 10 hours naturally - my body finally caught up with its sleep debt, and I was sleeping about 8 hours a day. I was amazed. Turns out I was just sleep deprived. Of course, I do know people who consistently get 9.5 hours day, so your mileage may vary. Just something to think about in this sleep deprived world.

Although, like most hot-air-pushers in these sleep threads, I never tried objective measurements of performance under different circumstances. Maybe I just _feel_ like shit, but actually perform well, with less than 9 hours of sleep.

This of course spells disaster for my normal work week. I still haven't gotten used to 24 hour days.

Source: I am typically underweight, and I have sleep apnea.

He does say you need to experiment and not take it as gospel. But there's nothing particularly new in that article, I've heard that story of Japanese office workers napping at their desk in the afternoon many years ago.

Sleep is a big deal, and not just because of the memory issue. Brains are expensive!

The post also doesn't seem to account for sleep debt. If you undersleep one night, you may have to sleep longer than normal the next night to make up for it.

The idea of sleep debt more refers to the long-term effects of a lack of sleep on your overall health. So if you skimp on hours of sleep during the week but then make them up during the weekend you might feel okay on Sunday, but you have actually physically harmed yourself in some minute way - you have created a sleep debt that you essentially cannot repay.

Also drinking water before you go to sleep works as a natural alarm clock.

In my personal experience I've known people who require 3 to 4 hrs/night, and others (myself included) who need between 8 and 9. During times when I'm feeling my absolute best, physically and mentally, I get about 2 hours of rigorous exercise, 8 to 10 hours of productive work, and roughly 8 hours of sleep a day with the rest of the time filled in by preparing and eating food, taking short breaks, hobbies, relaxing, etc.

Wild hypothesis: Most people would agree that the amount of sleep they require to "feel and do their best" (assuming ideal exercise, diet, etc.) falls within a normal distribution with mean 7 hours and standard deviation of +/- 3 hours.

--- edit: spelling

Yes, this would tire me out as well. :-)

Seriously, I've found that my normal schedule appears to be 7 hours solid, with a 1.5 hr nap, depending. Without an alarm, I wake up 7 hrs later on the dot (and can't get back to sleep), but then require a nap 8 hrs later to make it through the day. I cannot sustain 6 hrs and a 2-3 hr nap for any length of time (maybe a couple of days before I feel like crap).

I wonder how many different variations of these kinds of cycles there are among the population and how they vary from the 1st to the 3rd world.

As for the variations in the sleep cycles, I think it would have to do with the length of time between REM cycles in individuals. I'm sure there's individual variance in both the length of the cycles and how many cycles are needed for "A good night's sleep".

According to the UK's NHS website, adults need 7-9 hours a day, and it depends on the individual.

I started with 9 hours, every single night, going to bed and getting up at the same time. After less than a week, I started waking up 30-60 mins before my alarm. So I cut it to 8.5 hours, and then 8 hours etc.

With some refinement, I found somewhere just over 8 works. I really don't think it's any more complicated than that for most people.

The big problem is sleeping well and socialising a lot. The best approach I've found to that is to bank an extra bit of sleep when you can, although this is controversial.

My Dad always reminds me when I'm working hard: "the secret to stamina is sleep." It's a pain, but it's essential if you want to do good work and stay focused.

http://www.nytimes.com/2011/04/17/magazine/mag-17Sleep-t.htm...

All told, by the end of two weeks, the six-hour sleepers were as impaired as those who, in another Dinges study, had been sleep-deprived for 24 hours straight — the cognitive equivalent of being legally drunk.

My personal experience certainly tells me that a solid eight hours a night makes me far more productive than consistently getting six.

In order to make the best of your sleep cycle, it requires excellent sleep hygiene.

1. regularity is important. Going to bed and waking up at the same times weekday and weekend is very helpful.

2. sleep environment is important. simulating night time including shades, turning off message beeps, comfort, slightly cool temperatures make a big difference

3. eating - avoiding eating at least 3-4 hours prior to bedtime. Your blood sugar levels are easily disturbed and play a large part in your sleep cycle as glucocorticoids are active in sleep cycle.

The amount you sleep has a lot to do with your daily stress level, physical activity and damage your body takes.

hydrate like crazy, let your body perform its reparative miracles at night including memory consolidation.

I have noticed that people who have constant low-level death-by-a-thousand-cuts stress have many problems sleeping and getting quality sleep than those who have short bursts of high level stress. We are victims of our always-on world.

As another poster pointed out - Sleep is worth experimenting. Physical activity/exercise during the day helps.

I try to keep that routine during the week, because if i stay up too long only 1 night, it makes it more difficult for the rest of the week. I am more of a morning person anyway, rarely been very productive late at night.

For instance, last Saturday night, no sleep aid, I fell asleep around 5am, woke briefly at 10am, and woke completely at 1pm for a total of 7 hours. Last night, I took some AdvilPM (instead of my usual 3mg melatonin) at 10:30p, was in bed by 11p, and woke up this morning around 8a.

This might be because the sleep aid actually pushes me into waking up at the end of a REM cycle; I can't ascertain that. But I've found that the amount of sleep I get basically doesn't matter. Before I started with the sleep aids, it was random and infrequent for me to feel rested. I've been taking them for about a month now and it's sort of amazing how much better I feel.

(Also, as an aside, the first sleep aid I tried a year ago, a tablet of Unisom, did absolutely nothing for me. Also, 5mg melatonin seems to be too much for me. More data points.)

http://www.theglobeandmail.com/sports/hockey/sleep-doctor-ha...

Then again, my "sleep hygiene" is fairly bad overall: I regularly go to bed ~4am, I can rarely sleep for more than 5 hours without waking up (and I don't feel fully rested after that), and I usually spend 45-60 minutes snoozing my alarm before I get up (10-11am). Hopefully I'm not typical. I should probably get a sleep study done.

Four days to a week of severe sleep deprivation has been demonstrated to push the human body into a state of pre-diabetic crisis (per blood chemistry).

Another perspective: We enjoy sleep. There might be a reason for that, eh?

it felt like my metabolism had completely stopped, and my body was storing anything i ate as fat nearly immediately after i ate it. i was also bloated and gassy all the time. my diet was reasonably healthy (i wasn't eating pizza or anything like that, just normal foods like salads, chicken, occasional steak, some carbs, etc.)

it was obviously not good. btw i'm 30 years old, never felt this way before (haven't done a push like this since college age basically)

Now I set my alarm for 6h after I go to sleep (leaving 15m to fall asleep), have snooze set to 30m and max 3 times. Additionally I need to solve a simple math equation so I don't mindlessly press snooze. That way my amount of sleep varies on what my body feels it needs. Feeling way better since the change :)

Just an anecdote so take it however you want :)

About sleeping in general, I don't think that sleeping less than 8h per day is a myth. Nikola Tesla was sleeping 3-4 hours per day!

Recently I have found a cool website, which helps you to decide when to wake up or when to go to bed, so you can wake up fresh in the morning - sleepyti.me - bedtime calculator

I'm not sure how much science backs up most points in this post, but I can definitely attest to this point. It's so simple yet so effective. A quick 20-30 minute nap and I am buzzing with energy for the next few hours.

For example, if I go on cycling trips, I can do perfectly fine with 4-6 hours of sleep per day. On the other hand, during revision times when I try to cram as much as possible into my poor memory, I tend to sleep a lot, i.e. 12-14 hours per day (and work/revise for about 6, tops). Under normal conditions, I still prefer 8-9 hours of sleep (and conversely ~10 of work).

However, prior to exercising regularly I required much more sleep. Not sure this is anything but anecdotal, but I would be interested in seeing if fitness levels and sleep requirements have any correlation.

[1]http://youtu.be/8hAw1z8GdE8

It's called "bedtime guard."

Whether you call that time when you're awake "work" or not is irrelevant---I just meant that you're up doing something, even if its just reading or thinking or writing or whatever.

It seems counterintuitive but when you're properly rested, fit, and not using any real stimulatives/depressants, and you get in that rhythm, it works very well and comes naturally. Instead of 1 time per day of sleeping and waking up feeling great you get 3 times (pre-dawn, after dawn, then after your afternoon nap).

You just have to be able to do all 3 regularly to make it work, otherwise you skip a nap and you get screwed.

Is 'the same reason' that it's false? Your common sense and mine appear not to jibe.

Now this is something we have known for a long time! :-p

We are tuned by evolution.

More here: https://en.wikipedia.org/wiki/Segmented_sleep and I apologize for not finding a better source.

But even if you sleep 10 hours from 2am to 12 in the afternoon, it's far from enough or healthy.

A siesta is a nitro pack. Don't miss that in the game; especially if you live in a hot climate. I feel like blessed with a lot of bliss after I rise form my nap in my office sick bay(dorm/resting room/whatever) (I'm already smiling :-) ). My manager doesn't appreciate my 30-45 min nap everyday after lunch, I don't give a damn!

>>will be sleeping 24 years in our lifetime.

Indeed. So will we be peeing. So, what about recycle the water and keep it in our system itself. Will save the time of drinking water and then peeing. Double bonanza! This is absurd. You can't live life by remaining awake for longer period. For one, your life shortens and number and period of sunsets, sunrises and rains will not shift towards more if you start remaining awake more.

>>“Sleeping 8.5 hr. might really be a little worse than sleeping 5 hr.”

Now, either my biological clock needs a fix and everybody I know around me or his. Really.

My personal sleeping habit: I sleep at 11/12pm and almost everyday wake up at 6/7am. I never set an alarm unless either I've a VVI appointment - like with a doctor, a meeting or a flight to catch.

Why? Are you suggesting that the later in the day I fall asleep, the less healthy the sleep becomes?

Look, I am not a doctor or neurosomething and what I have said above in that statement is based upon my experience, other's and articles I've read. Besides, it's a well known fact that you need to rest your body and mind by sleeping at night at the right time and not just anytime.

> One of the biggest problems I’ve discovered is that sleep is such an over talked topic. We get the general idea that we know all about it: how much we need of it, how it impacts us and why this or that happens when we sleep. Once I took a step back to really think about where our knowledge about sleep comes from, I realized that nearly all of it is based on hear-say or what my mom told me when I was in elementary school.

I was merely quoting some well-known wisdom (among Chinese) (but not well-followed) from an old book [1] written based on actual clinical experiences. And it also happens to support fakeer's suggestion. If that's not up to some scientific standards, at least it is one step above "hear-say" and "what my mom told me", don't you think?

This is such a complicated subject, and I doubt there has been any concrete study that can conclusively prove anything. For me, the point of the article is to provoke exactly this kind of discussion.

[1] That's what the wikipedia article is about.

Scroll down and look for Circadian rhythm.

We stopped trusting in ourselves what to eat, how to sleep, how to walk and how to breathe, and when to go and relieve ourselves.

Everything must be boxed and timed.

Disconnected we are.