Why should I sleep?

November 11, 2007 2:12 PM

Why should I sleep? Like most people, I've always learned that it's important to get enough sleep. It's somewhat intuitive, as I am more alert during the day and feel better when I've slept enough.

However, now that I have a 14-hour-a-day job, it's not as easy to get my necessary 7 hours a night that I'm used to. With commute, showering, eating, etc. I usually have about an hour of free time each day if I get my full 7 hours. What I'm interested in, then, is whether there are any long-term negative health effects to not getting "enough" sleep. I know how it "feels" to only get, say, 5 hours a night, but I'm willing to feel a little less refreshed in the morning if it means that I have an extra 2 hours of free time a day. And I find that moderate amounts of caffeine allow me to think just as clearly and avoid dozing off when I'm functioning on low levels of sleep.

So...why should we strive to get 7-8 hours, besides the short-term effects of being sleepy? I'm interested in what the negative health or other effects there are, if any, of not getting enough sleep for a prolonged period of time. I'm aware of one study that suggested that weight loss was easier for people getting enough sleep, but that's not really a problem for me (yet) so I'm not so concerned. Are there other reasons to sleep?

posted by btkuhn to health & fitness (22 comments total)

Polyphasic sleep
posted by Brian B. at 2:32 PM on November 11, 2007

Yes, there is tons of epidemiological research connecting short sleep duration and cardiovascular (or all-cause) mortality over the long term. In experimental studies, short sleep duration produces glucose intolerance the next day. Many people take this to mean that chronic short sleep may harbor type 2 diabetes.
posted by a robot made out of meat at 2:35 PM on November 11, 2007

Study shows sleep improves memory and discusses the consequences of "sleep bulimia":

"If you look at modern society, there has in recent years been a considerable erosion of sleep time," says Walker. Describing this trend as "sleep bulimia" he explains that busy individuals often shortchange their sleep during the week -- purging, if you will -- only to try to catch up by "binging" on sleep on the weekends.

"This is especially troubling considering it is happening not just among adults, but also among teenagers and children," he adds. "Our research is demonstrating that sleep is critical for improving and consolidating procedural skills and that you can't short-change your brain of sleep and still learn effectively."

There is also an amphidromous relationship between sleep and depression.

Also, why is sleep important:

Long-term effects of sleep deficiency are diabetes (disrupted insulin production), weakened immune system (altered white blood cell production), obesity (decreased production of leptin, the chemical that makes you feel full), and cognitive problems (inability to store and maintain long-term memories).

posted by carmina at 2:41 PM on November 11, 2007 [2 favorites]

In addition to cardiovascular and all-causes mortality, chronic sleep deprivation also can produces memory loss, IQ decline (which lasts at least a year after the sleep deprivation ends), car accidents, elevated rates of accidental and non-accidental trauma, depression and other mental illness, and lowered resistance to infection. And those are just the studies I've seen.

Sleep when you can, as much as you can.
posted by ikkyu2 at 2:43 PM on November 11, 2007 [2 favorites]

And I find that moderate amounts of caffeine allow me to think just as clearly and avoid dozing off when I'm functioning on low levels of sleep.

This is one thing that's been studied extensively. Sleep deprivation causes performance to drop off on all kinds of tasks, but one common thread is that the sleep-deprived person consistently misjudges the quality of his work and says it's just as good as when he wasn't sleep deprived.
posted by ikkyu2 at 2:45 PM on November 11, 2007 [2 favorites]

Another problem with relying on caffeine as a substitute for sleep is tolerance buildup. Chronic overuse of caffeine has its own health consequences: high blood pressure, increased risk of stroke, kidney problems...
posted by Steven C. Den Beste at 3:35 PM on November 11, 2007

Look, if you don't sleep at all, you'll go bugfuck crazy and die, yes die, from not sleeping. Yeah, you're just trying to cut back on sleep, but that's like trying to cut back on oxygen, your body needs a certain amount and anything less just messes you up.

So quit screwing around with your health and try to work less or enjoy that one hour of free time..
posted by Brandon Blatcher at 3:53 PM on November 11, 2007

If you're especially interested in this topic, The Promise of Sleep is a great book on the subject. I remember that one of the negatives mentioned in the book was that too great a sleep debt plus a small amount of alcohol considerably increases the risk of having a car accident while driving.
posted by xo at 3:57 PM on November 11, 2007

One of my psychology lecturers subscribed to a slightly different theory.

He was once driving out in the middle of a country road at three in the morning, and he said it struck him just how dark it was. He stopped the car and pulled over.. turned the lights off, got out, took three steps and couldn't see a thing. His idea was that it was, in part, a protection mechanism - driving people to seek shelter, safety and most importantly others during a time we are vulnerable to nocturnal predators.

Of course, the general consensus is that apart from needing a certain amount of time to repair the body, produce certain chemicals that can't be made while awake, and so on, the body needs sleep as part of the process of forming long term memory, which would in part explain dreams - and a side effect of lack of sleep - paranoia.

A few anecdotes:

No one has proven that humans needs sleep to live, obviously. How do you keep someone awake? When you get tired enough you can sleep through anything. More to the point, killing someone for science is unethical.. but an experiment has been done on mice, where they were left on a constantly turning turntable, with food and water, for several days. The constant slow spinning made it impossible for them to sleep, and after a few days, they died.

Once in my first year of study i thought i would do a sleep deprivation experiment. Rather than sleep every night, I would sleep every second night, getting just enough respite from being tired to keep going. I lasted seven days. By the sixth i was getting pretty severe, irrational paranoia. When I was walking down the street, a car pulled up next to me, and I just *knew* they were spying on me, and I was under surveillance. On the seventh day, on campus, a university van pulled up in front of me to unload goods. But I knew better! I took a jump back, because they were about to run out, grab me, and bundle me into the back because I was crazy and they wanted to lock me up.

Then in class I started hallucinating.. so I started sleeping again. The whole week, after the first couple of days, all my time was spent "microsleeping", my head drooping, drooping.. eyes closed... AWAKE! drooping.. rinse repeat.
I might have been able to last longer if large parts of my day didn't involve standing still.

once, after doing some experiments on lucid dreaming, i tried meditating before bed. I allowed myself to relax, and be comfortable, but maintained awareness as much as possible.. eventually i did fall asleep, but i was conscious right up to the moment i fell asleep. the process of falling asleep was amazing. I'm not sure everyone is normally ignorant of it, but it was very interesting. My imagination got more and more vivid and erratic, to the point of me loosing conscious control over it, and there was a slow drift from "imagining things" to actually seeing them.

I also met a lecturer who never had visual dreams - his were all thoughts, sounds and ideas. Apparently it's quite common :)

anyway, hope something there engaged your curiousity. take it easy! :)
posted by Dillonlikescookies at 4:21 PM on November 11, 2007 [2 favorites]

No one has proven that humans needs sleep to live, obviously. [....] killing someone for science is unethical.

Actually, the Nazis did sleep deprivation experiments and found that humans will, in fact, die from sleep deprivation. Of course, non-Nazis have done similar experiments on a variety of non-humans and found the same thing.
posted by hattifattener at 4:47 PM on November 11, 2007

Slight off-top: J G Ballard has a good short story about a group of people who are enabled to live without sleeping.
posted by londongeezer at 4:57 PM on November 11, 2007

This study from a few years ago showed lowest mortality among people getting 7 hours of sleep a night.
posted by Zed_Lopez at 5:07 PM on November 11, 2007

Lack of sleep will make you crazy. Maybe even crazy enough to think that a 14-hours-per-day job is a Good Thing.

It isn't.
posted by flabdablet at 6:11 PM on November 11, 2007

What everyone said. Also, I've read that people who get less sleep are more likley to get diabetes.
posted by lunasol at 8:14 PM on November 11, 2007

In case anyone else wonders, the JG Ballard story is called "Manhole 69".
posted by exceptinsects at 9:45 PM on November 11, 2007 [1 favorite]

Well, my sleeping habits are fairly normal, 6-8 hrs a night fairly regularly. From time to time I need flexibility, and when I need to be able to function late at night or early in the morning, the best thing for me is to grab a 45 minute of 1.5 hour nap in the late afternoon or early evening. Probably adds about 3 hours to my waking day when I do it. The downside is that I occasionally find the need to sleep 10 hours straight if I overdo the staying awake thing.
posted by singingfish at 11:26 PM on November 11, 2007

Manhole 69 is a very good story, and pretty much sums up (though in a more extreme way) how I feel after significant amounts of time without sleep. You really do feel your psyche begin to disappear.

Anyway, experiments have shown that not everyone needs the same amount of sleep (although this is easy to determine anecdotally too!). If you feel crap after sleeping 5 hours a night for, say, a week.. then it's probably not going to be a long term solution for you. That said, I have found I can go with less sleep *if* I time the sleep to correspond the waking time with REM sleep. This is rather difficult, but can mean a 6 hour sleep feels refreshing, when a 6.5 hour sleep does not.
posted by wackybrit at 5:41 AM on November 12, 2007

There is a rare genetic disorder out there called Fatal Familial Insomnia which causes the sufferer to die from lack of sleeping. One day, in middle age, you abruptly lose the ability to sleep. And that's it. You never sleep again. Eventually, the sleep debt kills you.

FFI in the New York Times.
posted by jason's_planet at 7:22 AM on November 12, 2007

Unfortunately, sleep doesn't ask why or recognize scientific publications - it just comes for you anyway, and after enough sleep deprivation, you can't really rationalize it away. You just... zzzz.

In my personal experience, sleep is just above "I have to pee" at the very very bottom of my own hierarchy of needs; it doesn't matter what else is going on or how much I need to get done - if my body is telling me to sleep, I'd better freaking sleep. I'm much more likely to call in sick if I'm tired but otherwise healthy than if I'm suffering from a cold.

You can probably manipulate your sleep schedule a little bit, but if you're already feeling the effects of less sleep, you're going to end up crashing. And you will build a tolerance to caffeine, and any other stimulant you may be tempted to put in your body, pretty quickly. The two extra hours of free time each day aren't worth it if they make you feel crappy and irritable for all your waking hours.
posted by Metroid Baby at 7:23 AM on November 12, 2007

As someone with chronic insomnia problems, trust me, you really dont want to start voluntarily messing with your sleep needs. The world becomes a very very unpleasant place when all that debt starts to kick in. I've been up for almost five straight days with no sleep whatsoever and I'm convinced it was the very definition of Hell.

Previous from the blue.
posted by elendil71 at 11:00 AM on November 12, 2007

I have managed 9 months of 5 days a week * 4 hours per night ... hellish ... not reccommended
posted by jannw at 1:16 PM on November 12, 2007

As someone with regular bouts of insomnia, I'll second what just about everyone else has said: Don't do it.

Along with the studies I've read (diabetes, weight gain, cardiac risk, etc.) there are some nasty, nasty mental and emotional effects, and you're never as safe driving or as mentally alert as you think you are.

Get some sleep.

Also, I hope you really, really, really love that 14-hour-a-day job, but that's another story.
posted by mmoncur at 5:34 PM on November 13, 2007