High-quality sleep in 4.5 hours?
October 30, 2005 1:47 PM   Subscribe

Is non-harmful, restful sleep possible in only 4.5 hours a night?

A friend recently sent me a link to The power of the Sleep Cycle, whose author claims that sleeping 90 minutes in the evening and then 3 hours at night leaves him quite rested.

The idea behind this practice is that a sleep cycle is 90 minutes long, and that the way to make the most of sleep is to get in as many of these full cycles as possible. One source quoted in the article mentions that sleeping through a full four cycles (6 hours) of sleep may be more restful than sleeping 8 or 10 hours and waking in the middle of a cycle, but that hardly confirms the 90-minutes-followed-by-180 theory. In fact, the same source claims that the REM stages of the cycle get longer as the number of contiguous cycles increases, which would seem to indicate that I'd feel better after 7.5 hours (five cycles) than after just 3 hours (two cycles).

Nonetheless, I'm intrigued by the idea of getting only 4.5 hours of sleep a night, and I'd like to try it. I'm worried, however, about the long-term consequences, and, I must admit, I'm a bit skeptical about being able to function well on only three sleep cycles per 24 hours.

What's the science behind all of this? Will I be rested and happy after sleeping 4.5 hours, or am I destined for regret and caffeine?
posted by esd to Health & Fitness (28 answers total)
Probably works for some people, but not most.
posted by gramcracker at 1:52 PM on October 30, 2005

regret and caffeine. It's easier to wake up from sleep if you time your sleep period in multiples of 90 minutes (say 7.5 instead of 7), but it's still harder to get out of bed after 4.5 hours than it is after 9. So, if you have to get out of bed in 5 hours, set your alarm for 4.5. But in the long run most people need much more sleep than that. I would think you would have already noticed if you were one of those lucky few who can get by naturally on less than 6 hours of sleep.
posted by dness2 at 1:53 PM on October 30, 2005

I think my son does that at school and it works for him.
posted by konolia at 1:59 PM on October 30, 2005

Personally, I think all this "Sleep Less!!" stuff is yuppie BS. BUT, when I was in college and leaving all my work to the night before it was due, I found that sleeping for 4 hours would leave me much more rested than sleeping 5 or 3. It was much easier to wake up and I felt much more normal. This was once every couple of weeks though, I don't see it being a viable life style.
posted by crabintheocean at 2:00 PM on October 30, 2005

I agree...I read that the sleep cycle is 3 1/2 - 4 hours. It definitely seems better to only have one than sleep for 5 hours.

Apparently the 'natural' sleep pattern is to go to sleep at dusk, sleep for 3 1/2 hours wake up for a bit, then sleep again til dawn.
posted by lunkfish at 2:07 PM on October 30, 2005

I notice that the previous thread jessamyn links to has a post about the Uberman sleep schedule. Research that, or its proper term 'polyphasic sleep'. :-)
posted by PuGZ at 2:10 PM on October 30, 2005

Response by poster: Ah, thanks, jessamyn, and sorry for the semi-dupe. (When I did the search-for-past-articles bit, my search terms were more related to 90 minutes than to sleep in general.)
posted by esd at 2:13 PM on October 30, 2005

It often seems that not sleeping much is a mark of pride for some people. I think they often think that being able to get by on 3 or 4 hours of sleep is a sign of their hyper-intelligence and hyper-efficiency. It's actually more likely to be a biological fluke as opposed to some indication of superior intellect or whatever. From what I understand, (as dness2 mentioned) sleep needs appear to vary biologically from person to person...there's no trick to not needing sleep. You're either born that way or you're not Sure, Bill Clinton only needs 4 hours of sleep a night but Einstein needed 10 (or so I hear).

As for the whole 90 minute thing, I think that the concept is correct but the application of that concept is not. While waking up in the middle of a cycle might make you feel groggy, I'm not sure it makes sense that this grogginess would NEGATE any benefits of extra sleep to such a degree that it would be preferable to get less sleep in order to avoid this. I think this grogginess only makes it more difficult to wake up completely...it does seem to go away eventually.
posted by johnsmith415 at 2:15 PM on October 30, 2005

Response by poster: johnsmith415, I had the same impression about the 90-minute issue. The author of the post I linked to seemed to be using one study about pattern recognition indicating that 90 minutes of sleep was equivalent to a full night's sleep on a given task to conclude that getting 4.5 hours of sleep must be even better than a full night's sleep for the activities of daily life, or something along those lines.

My curiosity arose from wondering whether this fallacious conclusion was, nonetheless, accurate. So far, it seems like it probably isn't, at least for most people.
posted by esd at 2:24 PM on October 30, 2005

There's really no way to fully understand all of this until we figure this out. There are too many unknowns to offer definitive answers regarding sleep that works for everyone. Mysterious is still the word that makes the most sense regarding the brain and matters of sleep.

posted by Independent Scholarship at 2:33 PM on October 30, 2005

<librarian>tag searches for stuff like this are often more productive than the Googlebox I just went to http://ask.metafilter.com/tags/sleep </librarian>
posted by jessamyn at 2:42 PM on October 30, 2005

I am a clinical neurophysiologist, which means that I am a neurologically trained sleep specialist, among other things.

I like the answer that I've refined over three previous AskMe threads, so I think I'll repost it here:

The 95th percentiles of normal adult daily sleep need are 3 hours and 9 hours, and some healthy people require more or less to be rested. Although the range is wide, individual people do not vary much in their need for sleep - one of the 8-hour-a-day folks cannot become a 3-hour-a-day person.

You cannot train yourself to need less sleep. You can chronically sleep deprive yourself, which produces daytime somnolence, irritability and depression, decreased task performance, and other medical problems.
posted by ikkyu2 at 2:43 PM on October 30, 2005

Response by poster: ikkyu2, perhaps I can hijack my own thread to ask a related question that I didn't see answered on the sleep tag (thanks for the tip, jessamyn): how can I figure out what my daily sleep need is? Is it even possible when I'm working (i.e. not really able to allow myself to wake up as late as my body would like in the morning)?
posted by esd at 2:50 PM on October 30, 2005

Response by poster: Also, thanks for the responses, everyone. I'm fairly dissuaded from the notion that I should be trying the 90-then-180 thing.
posted by esd at 2:50 PM on October 30, 2005

I don't see why you wouldn't "try" it. These are not hard and fast numbers which anyone can say conclusively will or won't work for you. I say give it a shot, as an experiment. Try several things. And try to be a little bit scientific about it. Like choose some criteria for how "rested" you feel, and record your results every time. Perhaps some idiotic flash friday game will be of help. Play 3 games and average your score. That's your "score" for that day. Try each sleep configuration a few times in a row to give yourself a chance to adjust to it.

What's 90 minutes to one person might be 100 to you. If you're really curious, you'll have to experiment.
posted by scarabic at 2:59 PM on October 30, 2005

Read "The Promise of Sleep", by William Dement.... you will think twice about this idea of trying to find ways to get less sleep.

It hasn't given me the willpower to force myself to a better sleep schedule, but it was very educational and makes me realize what I'm doing to myself at least...
posted by twiggy at 3:02 PM on October 30, 2005

Hasn't sleep deprivation been linked (correlation, not causation) with hippocampal atrophy?
posted by NucleophilicAttack at 3:16 PM on October 30, 2005

I second the "why don't you just try it" comment. If you are interested in the uberman schedule, you may like to read Steve Pavlina's Polyphasic Sleep Log.
posted by davar at 4:04 PM on October 30, 2005

This kind of thing works for me sometimes, but
  1. I don't do it all the time.
  2. When I do it for a week or so, I need a big crash at the end
but other than that, the theory is sound. Better to have your early nap while i'ts still daytime, rather than at dusk of night time.
posted by singingfish at 4:58 PM on October 30, 2005

I would recommend trying it only if you have a few weeks with nothing much else to do. Don't expect any dramatic results.

I once tried to get used to various unusual sleep schedules, with relatively little success. All I really learned is that it is in fact easier to wake up at those 90-minute intervals. Oh, and it's not that hard to train yourself to be able to decide in advance how many of those cycles to sleep through before waking up.

I didn't find it all that hard to go to a "polyphasic" thing where I took a regular, short afternoon sleep. I did that for some time. It's okay, but it's nothing magical. I didn't find that I required any less total sleep time than I do otherwise.

I also tried sleeping only every second night, more or less. That, I can tell you, does not work at all well for me.
posted by sfenders at 5:13 PM on October 30, 2005

< anecdote grain="salt">

A year or two ago, I tried to convert from monophasic sleep to purely polyphasic sleep, and I ended up having panic attacks.

When I went back to monophasic sleep, they went away.

< /anecdote>
posted by adamwolf at 5:15 PM on October 30, 2005

The more sleep the better.
posted by davy at 7:35 AM on October 31, 2005

Hasn't sleep deprivation been linked (correlation, not causation) with hippocampal atrophy?"

I forget.

Oh, what was the question again?

(Does anyone else thiunk it odd that a neurologist is giving away free medical advice here? I don't mean it's bad practice or bad advice, I haven't enough info to gauge any neurologist's non-obvious advice, but that I thought MDs were supposed to be -- as in "by AMA rules" -- money-grubbing and fearful of lawsuits.)
posted by davy at 7:42 AM on October 31, 2005

Respectfully, Ikkyu2 is full of crap.

Perhaps this is simply because sleep is an endocrinilogical issue far more than a neurological one. Sleep cycles in the brain don't really tell us how long we need to sleep, they just tell us that the brain is cycling. Blood sugar cycles don't tell us what we need to eat. Hello?

Here it is again: You can do what you want, but the woman who knows everything is Eve Van Cauter, and she says sleep NINE or die trying not to. Uhh, literally.
posted by ewkpates at 9:17 AM on October 31, 2005

Ewkpates: "full of crap" isn't respectful where I come from. Be sure to wipe before you pull your pants up; you've soiled yourself and this thread, and it's starting to stink.

You don't even appear to be disagreeing with me, unless you're citing something in that registration-only site you linked.

Davy: Since I don't give medical advice out over the Internet, nothing you're mentioning applies.

If you notice, I mentioned a range in which most healthy normals' sleep need falls, and I pointed out some of the known consequences of chronic sleep deprivation. Nowhere did I diagnose any person or group of people, nor suggest that they follow any particular course of treatment. I'm sure you'll agree that's more along the line of didactic exposition than medical advice.
posted by ikkyu2 at 10:41 PM on October 31, 2005

esd: To figure out a person's daily sleep need, that person needs uninterrupted time when they can be allowed to sleep ad lib and awaken spontaneously, over a couple of weeks at least.
posted by ikkyu2 at 10:43 PM on October 31, 2005

Lots of information in the Polyphasic sleep article on Wikipedia, and the forum/wiki on polyphasicsleep.com
posted by Sharcho at 5:26 AM on January 1, 2006

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