Sleep Polyphasic
     A site about people with alternate Sleep Schedules

Sleep Phases

The basis of polyphasic sleep in general is that REM is the part of sleep that we really need. This articles discusses all the different phases of sleep.

Depending on how you look at it, there are roughly 3 phases to sleeping: Light sleep, Deep sleep, and REM (Rapid-eye-movement) sleep. Traditionally, these have been broken into Stages 1-4 and REM. But, if you look into it,
Stage 1 is actually a transition period between being awake (having alpha waves) and being in light sleep (consisting of theta waves).
Stage 2 is actual light sleep (theta waves, with sleep spindles and K-complexes).
Stage 3 is a transition between light sleep and deep sleep (delta waves), and
Stage 4 is true deep sleep, a.k.a. Slow-wave sleep where delta waves are predominent.
REM has always been considered a sererate part of sleep as it is very noticable with the eyes rapidly moving behind the sleeper's eye lids.

To repeat, the basis of polyphasic sleep is that REM is actually what is most important in sleeping. More acurately, REM rejuvinates the brain. It is not 100% agreed upon, but most people have agreed that REM sleep rejuvinates the brain and deep sleep rejuvinates the body. Most people need somewhere in the neighborhood of 2 hours of REM a day/night to rejuvinate their mind. The amount of deep sleep "needed" is significantly dependent on how old someone is, how much physical activity they do in general, how much physical activity they did that day (or the day before one could say for night-time sleep), and some other factors.

FOr some reason still not understood, REM cannot be obtain in big chunks, similar to how deep sleep is obtained. Rather, it is usually obtained in much smaller chunks. The first chunk when falling asleep for most people is about 15-20 minutes of REM. Later in the night's sleep, the amount of REM actually increases. At first, this seems odd. The mental feeling of tiredness is associated with not getting enough REM. So, wouldn't it make sense to get the REM out of the way right away. Well, yes and no, depending on how you look at it. Consider this about yourself. If you could only get 3 hours of sleep at night and still feel ok when you wake up, then wouldn't you probably only get tht much sleep on some occasions. But if, on the other hand, you feel tired unless you get 8 hours of sleep, then you are more likley to actually get the 8 hours, right. So, what our bodies do is first get the deep sleep out of the way so that we get that deep sleep and then move on to getting more REM once the deep sleep is "out of the way"