[David Hausladen]

This thread is meant to discuss how and why polyphasic sleep works. This initial post is based on the research and experimentation that I've done on alternative sleep schedules over the past few months. Of course, all of these points are open to debate.

I realize that many of my points contradict the most common understanding of polyphasic sleep, but I base my understanding of it on the work done by Dr. Claudio Stampi--pretty much the only scientist who's seriously researched polyphasic sleep. As you'll see, polyphasic sleep is not about REM sleep.

How "Long" Sleep Works

There are five stages of sleep: Stages 1 through 4 sleep, which are collectively called NREM (Non-Rapid Eye Movement), and REM (Rapid-Eye Movement) sleep. For our purposes, we can consider Stages 1 and 2 to be identical and Stages 3 and 4 to be identical.

Our sleep occurs in sleep cycles that average 90 minutes. About the first half of this is Stage 1/2 sleep. Next, we progress to Stage 3/4 sleep and then go into REM sleep. At the end of REM sleep we start another cycle, returning to Stage 1/2 sleep. Early in our daily sleep, we get proportionately more Stage 3/4 sleep, while later in our daily sleep, we get proportionately more REM sleep.

Stage 1/2 sleep functions mostly to get us from wakefulness to the other two stages of sleep. It does recover energy somewhat, but it generally doesn't address the deeper issues that manifest as sleep deprivation. In other words, it can bring you back from a short lull in energy, but it can't comprise all your sleep. It's much easier to wake from Stage 1/2 sleep, especially the first few minutes (Stage 1 sleep), than from any of the other stages.

Stage 3/4 sleep is what's most useful in fighting sleep deprivation. It's very deep sleep, though, and getting woken from Stage 3/4 sleep can leave you groggy enough to negate the whole benefit of the sleep cycle you were woken from.

REM sleep is most useful in the developing brain (i.e. during childhood), assisting newborns in proper nervous system development. Thus, the amount of REM sleep generally decreases with age. It's thought that dreaming only occurs in REM sleep, but dreaming can actually occur in any stage of sleep.

From an understanding of the sleep stages, it's clear that it's easiest to wake at the beginning of a sleep cycle, and doing so generally results in the maximum benefit for the sleep time gotten. In fact, waking from the wrong stage of sleep can cause enough of an energy drop that you can actually end up feeling more tired that you would with less sleep, but properly timed. So for planning out most sleep schedules, planning your sleep periods in unbroken increments of 90 minutes will result in the maximum benefit for the sleep gotten.

From what I've read and experienced, the body needs from 3 to 6 sleep cycles a night, depending on how consistent your sleep is and whether it's all together (monophasic sleep) or split into two or three chunks (biphasic or triphasic sleep).

If you plan your sleep around 90-minute increments and sleep consistently on that schedule, your body will eventually be able to shorten your sleep cycle so that it's 80 or 70 minutes, with the effect that you often wake up before your alarm.

How Short Sleep Works

In contrast to long sleep, we have short sleep. This is the term I use for the "Uberman" sleep schedule and pretty much any schedule which is based on sleep periods of less than 90 minutes. Given what I've said regarding the sleep cycle, why does short sleep work? 30-minute naps are not nearly enough to reach any of the really important stages of sleep. Claudio Stampi's second experiment with short sleep shows us the answer. (His first experiment was unsuccessful.)

Before Day 21, his subject's naps happened just as we would expect--that is, with only enough time for Stage 1/2 sleep. This is why pre-adaptation ultrashort sleep involves really heavy sleep deprivation--the sleep cycles needed to fight it off can't be gotten!*

*Keep in mind when you consider this 21-day adaptation period that the first 10 days included a gradual shift from 8-hour monophasic sleep to 3-hour polyphasic sleep. The "cold turkey" form of adaptation which is most commonly used today seems to adapt much more quickly.

On Day 21, the subject's sleep deprivation turned around. His naps changed from getting just Stage 1/2 sleep to getting all stages of sleep, and with about the same proportion of NREM to REM as in long sleep (though not the same amounts).

This is the secret behind the Uberman schedule and other short schedules: not that the body learns to only get REM sleep, but rather that the body learns to get all the stages of sleep without having to get an entire sleep cycle.

Another interesting factoid: the subject's mental performance was measured with two tests. Baseline levels were recorded at the beginning of the experiment (under monophasic sleep). On Day 21, his performance on one of the two tests jumped above the baseline and stayed there. A couple weeks later, he was allowed to sleep as long as he wanted for one sleep block, but then immediately returned to short sleep; this caused the other test to jump above the baseline and stay there. This gives us the rational for the idea of an occasional (weekly or monthly) long sleep inserted into a short sleep schedule.

The Applications: Sleep Schedules and Catnaps

The difference between long sleep and ultrashort sleep means you have long sleep schedules and short sleep schedules. All the monophasic, biphasic, and triphasic sleep schedules I've seen have been long sleep schedules; while all the schedules I've seen with 4 or more naps have been short sleep schedules (I've seen one exception to this, which is 4 naps of 90 minutes each; that's long sleep).

With a long sleep schedule, there's the concept of a catnap--a sleep period of 30 minutes or less. Because a catnap stays in Stage 1/2 sleep, it's easy to wake up from. It can be very useful for getting an energy boost in the middle of the day, but as stated above, it won't fight sleep deprivation. Sleeping longer than 30 minutes but not in increments of 90 minutes is not recommended since you'll likely wake up from Stage 3/4 sleep or REM sleep, doing yourself more harm than good.

One type of sleep schedule that's becoming popular is a sleep schedule with a core sleep of several hours and then a small number of catnaps. Despite the use of short sleep periods, this doesn't force the body to adapt to a short sleep schedule, so it's classified as a long sleep schedule. The most popular version of this is the Everyman sleep schedule, with a 3-hour core sleep and four 20-minute catnaps, which I'm trying now.

Other Issues, Ideas, Things I've Missed?

I know I've probably missed some things in here or failed to explain a few things well...there's a lot to this, and I've tried to summarize where possible. Please let me know if anything's unclear here or if you have ideas to add or that you want to discuss.

I hope this is helpful to you!