
Why Seven Hours of Sleep Might Be Better Than Eight - petethomas
http://online.wsj.com/articles/sleep-experts-close-in-on-the-optimal-nights-sleep-1405984970
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lnanek2
> And getting too much sleep—not just too little of it—is associated with
> health problems including diabetes, obesity and cardiovascular disease and
> with higher rates of death, studies show

I don't understand how people can honestly report stuff like this. If you are
sick, you often sleep more because you are drained and tired. That's plenty to
make the data look like that. Sleeping more doesn't necessarily make you sick
in the first place. There's no point bringing this up because it would be
silly to try to sleep less to improve your health.

~~~
streptomycin
I don't understand how people can think scientists don't know this. From the
article:

 _People who reported they slept 6.5 to 7.4 hours had a lower mortality rate
than those with shorter or longer sleep. The study, published in the Archives
of General Psychiatry in 2002, controlled for 32 health factors, including
medications._

Of course controlling for confounders does not magically mean their study is
perfect - there are always confounders that are either unknown or unable to be
measured, particularly in retrospective/observational studies like this. But
it's not nothing.

~~~
mreiland
correlation does not equal causation.

~~~
theandrewbailey
Posting those 5 words doesn't dismiss an argument. You could throw out a lot
of medical studies on that rule alone.

~~~
enraged_camel
>>Posting those 5 words doesn't dismiss an argument. While it doesn't equal
causation, it's a sure as hell cue that's something funny might be going on.

It may be a cue, but cues themselves are not actionable. They simply mean that
more research is needed until causation is found.

~~~
mreiland
If you look you'll see he edited his post to say something different after
your response.

The dishonesty itself is astounding and I wish people had more pride in
themselves than that.

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mickeyp
The solution for me -- believe it or not, call me crazy -- it to go to sleep
when I'm feeling sleepy and tired. I tend to read in bed; at least an hour
before I want to actually sleep, I'll read. Sometimes I get to the point where
I can't keep my eyes open after 30 mins in which case I pack away the book or
kindle and go to sleep. Sometimes I read a bit longer than the prescribed one
hour until I get to the point where I'm sleepy enough to go to sleep.

End result? I'm never tired in the mornings and I often wake up naturally
before my alarm clock rings. I also don't have massive "crash and burn"
effects on the weekends where I sleep for much, much longer.

~~~
lucian1900
If I do that, I sometimes will just stay awake all night and not fall asleep
at all. Very frustrating how hard I always find it to fall asleep.

~~~
saraid216
Me, too. Worse, when I go to sleep "naturally", the best case is that I don't
fall asleep at all and zombie the next day.

The worst case is that I _do_ fall asleep, but wake up broken in some way:
usually, it's cranial misalignment which gives me a massive headache the
entire day.

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Xcelerate
I didn't read the study (just the article), but it appears that the authors
are reporting their results for the "average" person. From what people say on
here, it seems to me that sleep requirements vary _a lot_ on a per person
basis, and what works well for one person may not work well for another.

People have different health conditions, different amounts of exercise per
day, different ages -- all kinds of factors. It seems that coming up with one
number for everyone is far too simplistic.

For me personally, I feel absolutely horrible on anything less than 9 hours. I
slept 7 last night and have been groggy all morning, even with 400 mg of
caffeine. Part of my problem is that I got mono last year, and ever since then
I've just been groggy in general. I asked my doctor about modafinil (which is
supposed to keep you awake), but he said it had a high abuse potential and
recommended corticosteroids instead. Meh, I'd rather have modafinil than
steroids, so I passed on the offer.

I'm at a conference all this week, and it's quite annoying being "that guy"
whose head is constantly bobbing during presentations even with sufficient
sleep. No amount of rest seems sufficient to eliminate my tendency to fall
asleep during lectures.

~~~
lilsunnybee
A sleep study might be a really good thing to do. Sleep disorders are very
underdiagnosed, and many are identified only from sleep study results. Many
many people with sleep disorders are completely unaware, and often go years
before being properly diagnosed, if at all.

Personally i've been diagnosed with narcolepsy, but it took 9-10 years of
problems and my life falling apart before any doctor caught it (finally having
insurance thanks to the ACA). Modafinil helps me to be a little more
functional during the day, and i'm really grateful for that.

Frequent dozing, microsleeps, like you're experiencing, even after a full
nights sleep, are indicative that there is an issue here worth investigating.

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tokenadult
From the article, "'The problem with these studies is that they give you good
information about association but not causation,' said Timothy Morgenthaler,
president of the American Academy of Sleep Medicine, which represents sleep
doctors and researchers, and a professor of medicine at the Mayo Clinic Center
for Sleep Medicine." Yep. It's painfully difficult and expensive to conduct a
good randomized treatment-control study of sleep duration with an adequate
sample size for figuring out what is optimal as a population central tendency.
I think the observation that many people put in a quiet, dark room in daylight
hours will fall asleep is one hint that more Americans get too little sleep
than too much sleep at night, but there is still more research needed.

When I used to live in the subtropical zone of Taiwan (the latitude of Taipei
is about like the latitude of Miami, and the climate is not greatly
different), there was still a fairly strongly established cultural custom of
taking a nap, a siesta, after lunch. It look me a long time to get used to
doing that, but it seemed to make sense, especially in the summer. Sleep
patterns vary somewhat by culture and by climate, but the big influence on
sleep patterns in the twenty-first century appears to be artificial indoor
light, which is much brighter and much less expensive compared to average
wages all over the world than it used to be. I always encourage people with
sleep problems to get outdoors IN THE MORNING DAYLIGHT for moderate exercise
to entrain their bodies' biological clocks. Behavior genetic research shows
that the biological clock genes are deeply conserved in most animals, so that
basically the same set of genes controls the biological clocks of both fruit
flies and human beings. Some flies (and some humans) have gene variants that
bring about problems like delayed-sleep-cycle sydrome, but essentially
everyone can entrain their biological clock by controlling light exposure.

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snowwrestler
This study relies on finding associations in a large data set, which is not
really a complete scientific study. It's at best a hint about where scientists
should conduct future research.

If you're just looking at correlations, it can be easy to miss hidden
variables, even when attempting to control for them with statistical methods.

Compare with a well-known Standord study where athletes were asked to maximize
their sleep, and then their results compared to when they got the "normal"
amount of sleep. They showed a notable improvement while maximizing sleep.

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hadoukenio
Ctrl-F sleep debt. Zero results found.

If you're reading an article on sleep studies and it doesn't mention sleep
debt, it's not giving the whole picture. Look up William Dement for more info.

Now just for a bit of info so it may help others... for years I had the
problem of going to bed around 10pm and then lying there awake for hours.
Sometimes almost to 1am. Classic insomnia, until I read a book on sleep by
William Dement, it all started to make a bit more sense - I was going to bed
too early for my body and not accumulating enough sleep debt...

So the solution was easy! Stay up later. Instead, I started going to bed at
around 11pm. I started falling asleep easier (within the recommend 20 minutes)
and didn't have the issue of insomnia any longer. However this _did_ lead onto
another issue - headaches. After years of suffering from insomnia I had found
the solution but then it lead to headaches. I chose headaches. But then I A/B
tested some more. I now go to sleep between 12am and 12:30am. Headaches gone.
Counter-intuitive, I completely agree. But headaches begone!

So IANAD (I am not a doctor), but if you're suffering from insomnia, try
staying up an hour later each night to accumulate a bit of sleep debt. And if
it's working but you're then getting headaches, try staying up another hour.
If you do experiment with this, shoot me an email (see my profile). I would be
interested to see if it works for more people or completely backfires.

(For the curious, I get out of bed at 5:05am every morning for work. So under
5 clean hours each night, no insomnia, no headaches)

Edit: I should have put more info on William Dement, otherwise people may
think he's just another fly-by-night "expert" \- Dr. William C. Dement, M.D.,
Ph.D., the world's leading authority on sleep, sleep disorders, and the
dangers of sleep deprivation. He is the director and founder of the Stanford
University Sleep Disorders Clinic and Research Center, the world's first sleep
disorders center.

~~~
andor
_for years I had the problem of going to bed around 10pm and then lying there
awake for hours_

Do you do any sports? Running or swimming for an hour (or cycling for two)
works well for me.

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lipoicacid
I run, lift, and do heavy Colorado trails at high heartrate levels. I find
exercise makes it generally more difficult to sleep. Has been a problem for
years, only get real sleep on my rest days.

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HNJohnC
Given what we now know about chronic cardio and it's incredibly damaging
effects on the body and the terrible consequences of losing sleep and the fact
that it's been a problem for you for years you sure sound resigned to it all.
I hope you don't suffer the typical consequences of such a dangerous
lifestyle. Consider reading this: [http://www.marksdailyapple.com/the-
evidence-continues-to-mou...](http://www.marksdailyapple.com/the-evidence-
continues-to-mount-against-chronic-cardio/)

~~~
andor
_Given what we now know about chronic cardio and it 's incredibly damaging
effects on the body_

That looks like FUD from somebody who's living depends on blogging FUD. Of
course, it's possible to train too hard, but this is very bad advice for the
average (slightly overweight, not very active) person. If you worry about
training too much, go talk to a sports physician and take a cardiac stress
test. Or just run so slowly that you can breathe through your nose only.

~~~
HNJohnC
Nope, science. FUD is pretty much what you replied with! :)

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laichzeit0
Actually the correct answer to "how many hours should I sleep?" is: it
depends.

I spend several hours a week breaking down my body by lifting extremely heavy
weights at the gym each week. I don't feel good with 7 hours of sleep. My body
needs to repair itself.

~~~
Amezarak
It's definitely not a fixed rule. I slept 7 hours last night and I feel
_miserable_ today, dull and tired. If I get 8-10 hours, I feel great.

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mschuster91
> "And stay off electronic devices a couple of hours before going to bed."

For many of us this will be the hardest part (and also a large source of sleep
problems).

~~~
carlob
You might want to try f.lux. Since the problem with electronic devices seems
to be blue light, changing the hue of the screen to a more reddish tone seems
to prevent the serotonin production inhibition associated with blue light.

~~~
gms7777
I love f.lux. I don't know if it has actually helped me fall asleep faster,
but I find myself getting a lot less eye strain when working at night. I just
wish I could find a similar app that actually works well for android. Any
suggestions out there?

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jre
Twilight is pretty good

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griffinmb
Though I rarely get it, I definitely feel my best after 12-13 hours of sleep.
I've never understood how the world seems fine with just 7 or 8.

~~~
k-mcgrady
If I sleep over 6-7 hours I find it incredibly difficult to get to sleep the
following night. The problem for me is I am perfectly happy sleeping 12 hours
:) If I actually obey my alarm and get up after 6 hours of sleep that seems
perfect to get me through the day (without caffeine) and fall asleep quite
quickly the next night.

~~~
mantas
Same there. If I sleep as much as I want (8-9 hours), my day tend to be 26+
hours. So I'd go to bed later and later. 7/17 formula works fine for me. I
feel dizzy with 6 hours of sleep only though.

~~~
k-mcgrady
That's exactly my problem. A few years ago I tried to follow that pattern. I
got as much sleep as I liked (8-9 hours usually) and went to bed when I was
tired. It just got later and later until I went to bed just before sunrise and
woke up just after sunset. Missing sunlight was actually quite horrible so I
ended the experiment after that!

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jeletonskelly
I was under the impression that 7.5 hours was optimal because it falls within
the recommended 7-9 hours and occurs at the end of a sleep cycle, which should
help you feel more refreshed and alert upon waking.

~~~
tbrownaw
Just keep in mind that nothing is exact. That "1.5 hours" is approximate, and
will vary between people, and will probably vary from night to night depending
on all sorts of things you'd never think of, and maybe between the start and
end of the night. Plus I'm pretty sure switching from "awake" to "asleep"
isn't instantaneous, so you have to count that time as well.

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andor
So the "health" section of the WSJ needed to come up with a story about sleep,
and found that many things correlate with the number 7.

The stone age-like study mentioned at the end, for example, simply found that
their participants slept longer when they had no access to electricity:
"subjective assessments of health and functioning did not reveal any relevant
changes across the study." So why 7.2 hours? Sunset at 22:00, sunrise (or
excessively loud birds!) at 5:30...

Even the title seems wrong. Sleep cycles take about 90 minutes each, so if I
plan to wake up after a certain amount of time, I pick a multiple of 90
minutes, i.e. neither 7 nor 8 hours.

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rthomas6
Sleep cycles don't all take exactly 90 minutes. The first one takes about 90
minutes, and each subsequent sleep cycle decreases in duration throughout the
night. The last sleep cycle before you wake up will take significantly less
than 90 minutes.

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falcolas
So, the article starts, and ends, with recommending 7-9 hours of sleep.
Everything in between mostly supports those two values.

What's the real answer, proposed by reality and this article? Find out for
yourself what your sleep duration should be.

Seems to me that the real purpose of this article was to remind folks that 5
hours is generally not going to be enough sleep, and 10+ hours might be a sign
something's wrong.

To add to anecdotal evidence: What's worked for me is having a set wake-up
time every single day of the week, and going to bed when I'm tired. Turns out
I naturally want right around 8 hours of sleep, give or take 30 minutes on a
day-to-day basis.

~~~
blarara
but how do we know much of that "naturally" is actually from decades of
sleeping ~8 hours of day

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nevinera
I find research that starts with the assumption that humans require identical
amounts of anything to be absurd. People are metabolically different from each
other - the optimal average has no bearing on what _I_ should do, it only
indicates the course that is most likely to be correct, _ignoring all specific
information about myself_.

I have a lot of information about myself that differentiates me from the
aggregate (and so should most people), so this recommendation is more
dangerous than it is useful.

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blarara
I wonder at which point in time did we stop going to sleep when we were tired
and just started subscribing to some random number like 8 hours of sleep per
day.

Humans are so stupid.

~~~
krapp
The Industrial Revolution, probably. You can't simply "go to sleep when you're
tired" when you have to allocate x hours to labor per day - everything you do
is synchronized to either education hours or work hours for most of your life.
So 8 hours of sleep with 8 hours of work and 8 hours of leisure per day.

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Cthulhu_
I'm seeing lots of researches being cited here, but, were those people
healthier because they got less than 8 hours of sleep, or was there some other
factor causing them to get / need less sleep which also helped their health?

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garrickvanburen
7hrs is completely consistent w/ my current, quite sustainable, sleep pattern.

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pyrrhotech
I sleep 8.5-9 hours a night. I feel like shit if I get less than 8. I think it
largely depends on the person

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szatkus
How about... 3?

