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POLYPHASIC SLEEP

A term coined by early 20th century psychologist J.S. Szymanski, refers to the practice of sleeping multiple times in a 24-hour period

REM SLEEP

REM sleep in adult humans typically occupies 20-25% of total sleep, lasting about 90-120 minutes. During a normal night of sleep, humans usually experience about 4 or 5 periods of REM sleep; they are quite short at the beginning of the night and longer toward the end.

The theories behind the function for REM include:

  1. Memories are consolidated during REM sleep. Nfunctions are not measurably affected.
  2. Monoamine shutdown is required so that the monoamine receptors in the brain can recover to regain full sensitivity. Acute REM sleep deprivation can improve certain types of depression, and depression appears to be related to an imbalance of certain neurotransmitters.
  3. Active Sleep is particularly important to the developing brain, possibly because it provides the neural stimulation that newborns need to form mature neural connections and for proper nervous system development. Further supporting this theory is the fact that the amount of REM sleep

NON RAPID EYE MOVEMENT SLEEP

NREM sleep is divided into four stages:

  • Stage 1 - occurs in the beginning of sleep, with slow eye movements. People in this stage often believe that they are fully awake. During the transition into Stage 1 sleep, it is common to experience hypnic jerks.
  • Stage 2 - the person is unconscious though awakened easily. No eye movements occur, and dreaming is very rare during this stage.
  • Stage 3 - transition between stage 2 and stage 4. Delta waves begin to occur which are associated with “deep” sleep.
  • Stage 4 - slow-wave sleep (SWS) refers to the “deepest” stage of sleep in which there is a continuation of the delta wave. Dreaming is more common in this stage than in other stages of NREM sleep though not as common as in REM sleep. The content of SWS dreams tends to be disconnected and not as vivid as those that occur during REM sleep. This is also the most common stage in which parasomnias occur.