I actually studied this for a report I did at work (pilot rest/sleep schedules and the science behind it). I was able to talk to some sleep experts, which was pretty cool. Anyway, I learned a lot of things:

1. Night/darkness encourages the release of chemicals (melatonin) in your body that make you feel sleepy. That's why they recommend that you dim the lights at night and don't use your computer/watch TV in bed. I have employed this method and have had decent success with helping my brain wind down from the day.

2. Sleep happens in cycles. Many infants wake up after their first sleep cycle and can't get back to sleep. If you hear a noise during one of these partial awakenings, you are likely to wake up, whereas the same noise would not wake you up if you were in a deeper sleep. Some people don't realize that they've woken up and get right back to sleep; others wake all the way up. This is why they emphasize putting babies down while they are drowsy but still awake - they learn to fall asleep on their own and are more likely to put themselves back to sleep after a partial awakening too. I would assume that this can affect adults who have not done sleep training or who naturally wake up more during a partial awakening in the middle of the night. Alcohol can wake you up during one of these partial awakenings because it increases your body temperature (making you uncomfortable and aware of it while partially awake) and therefore reduces the amount of deep sleep you get.

3. You can make up lost sleep, and you make it up fast. For example, a sleep deficit of 20 hours does not require you to sleep 20 additional hours to make it up; you can probably do it in 10 or so hours. What you cannot do is bank sleep for the future.

4. Sleep deficit increases stress hormones in your body and promotes weight gain. This can cause you to have further problems falling and staying asleep.

5. When you reach your 30's, your body stops making some of the chemicals that keep you asleep for long periods of time. It doesn't mean that you need less sleep, just that you are not capable of getting it in one sitting. This is why older people often don't sleep long at night, but then fall asleep on the couch. Oh sorry, grandma is just resting her eyes...

6. Lastly, people need different amounts of sleep. 8-9 hours is an average, but some need more or less depending on their hormones and levels of activity. What was stressed to me and my research team was the time needed to unwind and relax. People who are stimulated for 10-12 hours will need a good 9-10 hours to clear their mind and mentally rest so that they can be alert for work the next day.

That is one hilarious (and juvenile!) cartoon!

I have trouble going to bed early enough. On weekends, I find myself taking long afternoon naps to "catch up", especially if I had finished a long or hard bicycle ride in the morning.

@Revy agreed

Someone should make a Tshirt that says 'There is an XKCD for that'

There is, of course, an XKCD for this.

That's the one.

Superman, Uberman... You can see my confusion...

@JonJon: is it possible you are confusing it with the Uberman, with 6 naps 20' long evenly spaced during the 24h?

Does anyone know anyone who's actually tried the "superman" monophasic sleep regime where you train your body to snap into instant REM, and can be awake and productive for 22 hours a day?

I've never heard of that, but it seems physiologically possible to do. I think you'd need at least a couple hours of quiet, wakeful downtime, though, in addition to the two hours of "supersleep", to let your body physically recuperate from the day's activity. You could spend it awake and mentally working on your next project, as long as you laid there quietly while you did it.

Kodie, as far as sleep deficits go, I've heard that you can actually make up lost sleep, and even "stock up" on sleep for later, within about a two-week window. Any bigger window than that, you don't get any benefit.

My mom used to sleep huge amounts. 10-12 hours a night and a solid 3-4 hour nap. She was later diagnosed with a thyroid disorder, and now sleeps a "normal" amount. I've also heard that some people just need more or less sleep. Some famously productive people reputedly only needed 4 hours a night.

Does anyone know anyone who's actually tried the "superman" monophasic sleep regime where you train your body to snap into instant REM, and can be awake and productive for 22 hours a day?

I learned recently from a bullshit tv program that 8 hours is the wrong amount. It may be true even though it's from daytime tv. The consultant says the body sleep/REM cycles on 90 minute intervals, which is why I find it easier to wake up after 3 hours than after 4 or 5. I mean, that seems to explain something. I have poor sleep habits, I go to bed too late and wake up whenever I wake up. This morning, it was 6 hours. I have heard that it's impossible to "catch up" on sleep if you have been getting too little sleep for a sustained period, like all weekdays, and then get those Zzzzzzzs made up on the weekend... I don't know about that. I don't understand this. If I get too little sleep for a while, I know I feel more sleepy, like laying down, can't hold my head up, and sleeping a lot more. One time, I slept almost 24 hours in a row, with no signs of other illness (or hangover), I'd get up for 2 hours or so and then go back to bed for 5 or 6 or 9 hours in a row, get up. I definitely felt more rested by the end of it. If you lose sleep and then it's "gone forever" and you can't "make it up" some other time, where does it go and why do I feel an accumulation of tiredness so large that I must obey from time to time, such that I perceive that I have caught up and feel perfectly rested?

I could definitely see the idea of sleeping a few times a day for shorter periods, but I've been conditioned to only sleep in one block. A nap feels like a failure to me. I have tried to figure out what that (5-hour energy commercial) "2:30 feeling" is when it hits - and it really does! - is more of a crash and try to consume different food and drinks at different times so to avoid it and have more dependable energy through the day. When I get that crash fatigue, it's so severe that I can't do anything.

Nothing wrong with that approach, Revy. Lying quietly is all your body needs to recover from physical exertion. Sleep is not required for that; in layman's terms, it's only needed for sorting out the day's experiences and keeping a complex brain from going crazy.

Or so they said when I learned about the subject decades ago. I'll confess that I'm not up on the latest sleep research. LRA could probably give you a better picture.

Ive never slept much. These days, 5 hours per day is about all I need to keep bright eyed and chipper. Even when I was a baby, I rarely slept more than 8. It freaked my mom out, every time she came to check on me, I would be wide awake and playing. What's weird is when I wear my body out (which has been quite often recently) I need quite a bit of physical rest, but my mind won't do the sleepy thing, so I spend my time reading or just letting my mind wander. Hopefully, we can get caught up at work soon, and I can stop this 70hour work week crap.

I am considering that I can't do this until I solve my depression.
Sleep is the only moment where I get respite from existence.

Young people sleep longer. You'll outgrow it soon enough. :)

If I'm left alone, I'll usually sleep 12 hours. In some cases I've slept 16 hours in a row.

If I go to bed early, I wake up early. I will sleep at least 6 hours at night, usually 7 and almost never 8. Probably half the time I take a 1-hour nap in the middle of the day, and on rare occasions a second nap. Overall, I average 7.5 to 8 hours of sleep per 24 hours, about three-quarters of it in one long stretch at night.

Last night I fell asleep around 10 p.m., and I woke up a little before 4:00 a.m. this morning. I'm up, alert and functioning (some credit is due to the coffee), and I expect to be active for several hours and then nap in late morning before starting a second round of activity.

It works for me. Sleeping a single eight-hour stretch a night, and sleeping only at night, is a cultural norm and not a biological one. I think that a lot of self-diagnosed sleep disorders are simply the assumption that a solid eight-hour block of sleep is the only normal, healthy way to do it.

Of course, what sleep patterns you are able to practice will depend on a lot of things, the primary one being your job schedule. People who sleep best in installments but who have only one eight-hour chunk of time available for sleep due to other scheduled activities are pretty much screwed by the modern American schedule.

If I go to bed too early I just won't sleep.

strange. maybe i should try something like that, i can never feel rested when i try to sleep eight hours straight. at least not if i'm getting up before 8:00...but i have no idea why, i go to bed early enough, it just doesn't work ever

I've definitely done four hours of sleep a night and a two or three hour nap during the day for several months at a time. I don't have any trouble with it at all, actually.

My little brother follows a polyphasic sleep cycle. I'm not sure exactly what times he wakes up or goes to sleep. My best guess is that he gets half his sleep after school, wakes up in the evening, goes to sleep around midnight, and then wakes up around 4 or 5 am.
He seems to really like it and he says he feels much more awake. I think it would just confuse me and it would probably make going to work or hanging out with friends a lot harder.

My understanding is that polyphasic sleep was the historical norm in Europe and the U.S. It typically took a biphasic form, with an hour or two of being up and about in the middle of the night before returning to bed. Modern industrial society has eliminated this sleeping pattern, for reasons that I do not know.

Cultures that observe mid-day siestas can also be said to practice polyphasic sleep. It's a good way to dodge the peak temperatures of the day in hot climates.

Physiologically, the only requirement is that you get enough REM sleep. Studies have shown that humans are highly adaptable in this regard; if you do the experiment where you never let subjects sleep for longer than twenty minutes at a stretch, they will begin to enter REM sleep very quickly, instead of an hour or so after falling asleep.

I know less about the effects of intermittent fasting. I do recall studies that demonstrated in humans that, for a constant amount of calorie consumption, fat storage and weight gain were significantly lower in the group that ate many small meals over the course of a day, compared to the group that took in the same amount of calories in only two or three meals.

Regarding the first, I remember something like it worked on rats but not in humans.
At the same time it does make sense that eating 3/5 times per day may be too much.
Still, any evidence seems inconclusive.

Regarding polyphasic sleep, do you actually know anyone who practices it?