Now, I'm certainly not an expert on sleep, but my current night reading just happens to be "The Promise of Sleep" by Willam Dement, founder of the Stanford sleep center and student of Kleitman, the discoverer of REM sleep. And this article contradicts what he writes in so many ways. Here's what I took away from the book:
Just as a start, the author got that thing about REM sleep being the only sleep that matters exactly backwards. Depriving people of REM sleep has not shown any effects on increasing sleep debt (ie feeling tired), it's the non-REM sleep that you need to not feel tired. (Which makes sense because in REM sleep your brain is essentially awake.) What the purpose of REM sleep is, is not known.
Furthermore, the idea that you can "train" yourself to need less sleep has no basis in science. This does not mean there aren't a few people who have all kinds of strange sleep issues, but for the majority of people there seems to be no scientific evidence that this works at all.
About the "intrinsic 28-hour pattern", in most cases (not all, there are probably people with real physiological disorders) this tendency to have a longer day than 24 hours is induced by artificial light in the evening. Electric lighting, and certainly staring into a bright LCD screen, is bright enough to register as daylight to your biological clock, and cause it to shift forward. In studies where people were isolated from artificial lights, people who normally would have a rhythm slightly longer reverted back to almost exactly 24 hours.
Rather than "hacking your brain", it would probably be more beneficial for the majority of people to just learn about how sleep works and of the importance of managing it properly.
I am trying to find a couple primary sources to back up your suggestion that I got the REM/other phases backwards. That would be quite embarrassing, but I am pretty sure I am correct. Does anyone know of any of any good studies done on REM deficit?
Polyphasic sleep does not train the body to "need less sleep" directly. But it appears the body adapts to use the naps more efficiently than it would use a longer chunk of sleep. To suggest there is "no basis in science" for this seems kind of a stretch. There is science that describes this process.
I'm aware that people claiming to have messed up biological clocks tend to have environmental or physiological factors that cause the problems. I have done pretty much everything sort of isolating myself from artificial light for a period of time longer than about a week, and my body is stuck on a 28-hour clock.
Also, you suggest that people deprived of artificial light snap into a "exactly" 24-hour schedule. This is actually not correct. Many studies have been done showing that the default schedule ends up being about 25 hours when you deprive people of clocks and light sources.
Also, you suggest that people deprived of artificial light snap into a "exactly" 24-hour schedule. This is actually not correct. Many studies have been done showing that the default schedule ends up being about 25 hours when you deprive people of clocks and light sources.
According to the book, the 25h result was a result of previous studies not controlling the presence of lights carefully enough (just a single light bulb in a room is bright enough to make a difference), and when this was recognized, the natural circadian period was ~ 24h 10m. This was a study by Chuck Czeisler at Stanford and has apparently been confirmed by other studies.
This is of course anecdotal, but a few years back I did the polyphasic experience, and I can confirm that dreaming consistently occurs during those 20 minute naps, which strongly suggests REM sleep. In fact, those dreams were some of the best and most vivid dreams I've ever had, presumably because you're never more than 20 minutes away from consciousness, so you remember the dreams clearly, and the dreams are strongly correlated to your mental state going into the nap.
Everyone should try the polyphasic experience for at least a few months of one's life. It radically alters the way you think about time.
To reference Dement's book again, this seems to be well established. If you deprive people of REM sleep, it will start occurring sooner and sooner after falling asleep, so that after a while the subjects would fall asleep and start dreaming almost instantly. (Which made the experiment difficult to continue since the subjects would get very angry after being repeatedly awoken immediately after falling asleep... ;-)
The first week of going polyphasic involves substantial sleep deprivation. You are basically worthless for 1-2 weeks, though you can catch up on some light reading (as I recall, I used the opportunity to dig back into PAIP...).
After a couple of weeks though, you are really refreshed by those 20 minute naps. It's rather amazing. You wake up much more alert and ready to take on the world than after any normal 5-8 hour night of sleep. And you can continue on this pattern, sleeping only 2-3 hours every day, for a seemingly indefinite amount of time, while feeling great.
That's the personal anecdote that appears (with a small and self-selected sample) to contradict your interpretation of Dement's statements.
I did an uberman polyphasic schedule for a year and everyman for about 6 months. Stage N1 is likely an adjustment period where your body rhythms slow down and things get ready. Studies have shown that stage N2 and N3 (deep cycles) are essential for healing and muscle growth- they are also when HGH hormones are released. REM has shown to be essential for memory retention and some studies have linked lack of REM to schizophrenia and other psychosis.
When I was polyphasic, roughly 70% of my polynaps were REM and 30% were deep cycles. Interestingly, if I was sore from a workout or something, it would continue to be sore until I had a deep cycle.
Despite the vast, vast multitude of sleep studies (and departments, and journals) out there, I've only seen one study on polyphasic sleep and it was very exploratory. People who study sleep at all immediately associate it with sleep deprivation, which has been studied so much all they can do is spew forth the negatives (there are tons) associated with it. The premise of functional polyphasic sleep is that the body actually adjust so there is no sleep deprivation.
I didn't end up blogging about it, and I don't write about it much, because frankly, after doing it for a month or so- when I was really well adjusted- I ceased having something to prove. It kind of feels like talking about my bowel movements or something. I guess it could be vaguely interesting to someone, but it bores the crap out of me (forgive me).
So quickly: I would not recommend it. You can't exercise much, the adjustment period is very, very difficult (only 10 days, but that's 6 naps a day == like getting up way earlier than you wanted to 60 times in a row. Most people can't even get up earlier than they want to once in a row.) You need an environment where you can have all the lights on and make all the noise you want all night. You can't have other people imposing meetings or any kind of schedule on you. You can't do anything that takes longer than 4 hours. And here's the real kicker: you can't work for more than ~50 hours a week without getting burned out! Yeah, having more hours doesn't help that. And don't even think of starting it if you have something remotely stressful coming up or not enough to do. And don't think of starting it if you live somewhere where it's cold at night. Etc.
All the debate over the health effects are meaningless- it's people who haven't experienced it or frankly studied it. Sleep deprivation only applies in the first 10 days. After that it feels far less harmful then, say, caffeine. shrug
EDIT: Hypothesis (in case someone actually wants to _study_ it- I sure couldn't find any takers when I was doing it): The body seemed to eliminate N1 altogether- my heartrate and body temperature would drop within 30 seconds of lying down- for over a year. 2nd part of the hypothesis- the the first one or two REM cycles at night are essential and the rest is padding built in by evolution to keep you asleep until dawn. 3rd part- other body functions relying on the circadian rhythm adapt- especially digestion, which is _totally_ different when fully adjusted to polyphasic sleep. 4th- there is a reservoir of... something... built up for when you get injured or sick by having that extra sleep in monophasic sleep.
Also, I stopped because I got lazy.
Finally, if you get colds easy, don't even try. A single cold will wipe you out for a day or more.
What do you mean with you got lazy? Were you too busy (eg meetings) keeping the right sleep schedules? How hard is it to wake up at the right time if you are accustomed to it?
If you would have the possibility to do it again, would you do it again?
lazy- yes. We were moving from Maui back to the mainland and between logistics and the kids and everything my sleep schedule got totally chaotic. Then when we were here on the mainland I wasn't in a position where I could have lots of lights on, cook, and make noise during the night.
I stopped using an alarm clock after about a month- so for 17 months I didn't even need an alarm clock after I was accustomed to it.
Doing it again... yes, if the circumstances were just right. Looking back now I realize I was in a unique position with work, family, stress levels, weather, etc. It took a couple of weeks to adjust back to a monophasic schedule- and it was not fun. I'm not excited for the adjustment back to polyphasic sleep. But yeah, I might do it again after our move to Silicon Valley later in the year.
Dement's book does not have any real references, but on p 257 he discusses a study by Tom Roth and Tim Roehrs where paired subjects were awakened when one of them entered REM sleep. The pairs thus had identical sleep disturbances and were different only in whether they were woken up in REM sleep or not. He says
"The results were striking. The daytime sleep tendency did not change in the REM sleep-deprived group ... whereas the yoked control group (which lost much more non-REM sleep) became significantly sleepier in the daytime."
To be fair, he then goes on with some cautionary notes about the small numbers of the study and how some older studies had not found a difference. There was no mention of studies finding the opposite, though.
Yeah, there appears to be very little hard research on the subject, but my personal experience from reading neuroscience journals has led me to the understanding that REM sleep removes tiredness. In fact, people with REM sleep behavior disorder -- that is, people who naturally do not go into REM sleep normally, and when they do, they have odd physical behaviors -- complain of chronic tiredness and sometimes end up with serious mental disorders.
The other phases of sleep are even less understood than REM, so I am going to trust my instinct and go with the real research that has been published on polyphasic sleep.
"Why We Nap" - Stampi - next to impossible to find. It coined the word polyphasic (and monophasic) sleep.
It's exploratory, but pretty good science. It's basically a study of solo sail-boat racers- long distance. They have to get little naps in, but they have to stay awake enough to take advantage of wind and water currents for days and days.
Other than that, at least last time I checked a year or two ago, all sleep scientists had written it off as "sleep deprivation" which they feel they already have a good handle on (it's evil), and therefore they are very disinterested in actually studying it.
Also, I remember reading a study where rats were deprived of REM cycles and the result was they were never exposed to nightmares. The hypothesis was that nightmares prepare us for real world dangers, and once the rats stopped dreaming, they were also less skittish in dangerous situations. I'll try to find the article again after work.
there seems to be no scientific evidence that this works at all
Do you know if there has been a serious scientific study of this technique? Otherwise, you're being a bit disingenuous in subtly applying the "unscientific" label. The set of things that are true is much larger than the set of true things that have been proven scientifically.
Like I said, I'm just restating what I read in Dement's book, which hasn't talked about this technique at all except to say that people who wake up frequently (like people with sleep apnea) are much more tired than they should be, because the awakenings actually don't change the total amount of sleep that much. So there seems to be evidence indicating that many short chunks of sleep are less effective at reducing sleep debt than one chunk of the same total length. It's as if there's a "startup cost" to falling asleep, and it doesn't start to benefit you until after some time has passed.
So I should have formulated myself more carefully by saying: Studies indicate that short periods of sleep is less effective than long ones, and that each individual requires a certain amount of sleep per night (but which varies with individual and then as you age).
He did go so far as to say something about how he thought methods advocating that you can train yourself to sleep less are "dangerous", given how much sleep deprivation affects your health and ability to do things like drive or operate other machinery safely.
What I worry about is recent studies that suggest that declarative memories (memories of events, objects, and so on) are consolidated during slow-wave sleep. I'm thinking specifically of Rasch et al., 2007 (DOI: 10.1126/science.1138581).
Since the theory behind these polyphasic schedules is that it mainly reduces the time spent in slow-wave sleep, I would expect that the declarative memory would be affected.
This study http://www.oniros.fr/A1350.pdf seems to indicate that sleep duration has no effect. Their interpretation is that a process is triggerd when you enter sleep but once triggered it is independent of wheter you sleep or not.
You are definetely right but let me just comment about the physiological exception.
In the in the case of this blog post the might actually be some differences. The writer may really have some genetic problem in his/her circadian clock. Sleep is known to be under regulation of two mechanism: a circadian mechanism (about 24 hour for most of us) and a homeostatic mechanism. It is known (it is actually one of the few things we actually know pretty well about sleep) that the NREM is under control of the homeostatic mechanism while REM is under control of the circadian mechanism.
The blog author has a longer cycle and it is likely that his/her REM kicks in later on in their night, therefore being incompatible with obtaining enough REM. By doing polyphasic he/she might be able to compensate for that.
I was thinking of that study of a guy who lived without clocks for several weeks (I think it was underground), and he tended to a 25-hour pattern (IIRC). But of course (apart from the sample size), he had electric lighting.
That explains why I slept so well when I was locked up (back as a young'n in juvie): You didn't have control of the light in your cell, so from ~10pm to ~7am lights were out whether you liked it or not. I'm a life-long insomniac.
The reverse - going to sleep as the sun creeps up - is difficult for me. It feels worse to me to try to sleep as dawn comes than just an hour earlier.
I'd expect to fall quickly and pleasantly asleep after an all-nighter, but the combination of dawn, the pounding of my heart and racing of my mind actually leave me awake and thinking for an extra few minutes. It's possible that going to sleep in that state gives me extra insight on what I was working on, but it doesn't feel good.
Interestingly, the effect of light on the biological clock reverses in the middle of the night, so that light in the early morning tends to make the cycle shorter. Which I guess also makes sense since that's how it would have to work with jetlag.
Just as a start, the author got that thing about REM sleep being the only sleep that matters exactly backwards. Depriving people of REM sleep has not shown any effects on increasing sleep debt (ie feeling tired), it's the non-REM sleep that you need to not feel tired. (Which makes sense because in REM sleep your brain is essentially awake.) What the purpose of REM sleep is, is not known.
Furthermore, the idea that you can "train" yourself to need less sleep has no basis in science. This does not mean there aren't a few people who have all kinds of strange sleep issues, but for the majority of people there seems to be no scientific evidence that this works at all.
About the "intrinsic 28-hour pattern", in most cases (not all, there are probably people with real physiological disorders) this tendency to have a longer day than 24 hours is induced by artificial light in the evening. Electric lighting, and certainly staring into a bright LCD screen, is bright enough to register as daylight to your biological clock, and cause it to shift forward. In studies where people were isolated from artificial lights, people who normally would have a rhythm slightly longer reverted back to almost exactly 24 hours.
Rather than "hacking your brain", it would probably be more beneficial for the majority of people to just learn about how sleep works and of the importance of managing it properly.