Sleep Cycles

NORMAL SLEEP PATTERNS – YOUNG ADULTS

 First pass through a stage of relaxed wakefulness

Stage 1 Sleep
Stage 2 Sleep
Stage 3 and 4 Sleep or Slow Wave Sleep (SWS)
Stage 2 Sleep REM

The completed sleep cycle usually occurs ever 90 minutes with the first REM period lasting anywhere from two minutes to an hour.

The second sleep cycle begins and continues as the first cycle, with REM becoming more defined and lasting longer. As sleep progresses, the cycle is usually between Stage 2 and REM sleep, with REM lasting longer with each progressive cycle. Most individuals awaken out of REM in the morning when allowed to awaken naturally.

Children spend more time in SWS and REM.

Aging adults spend more time in Stage2 and REM.

In REM sleep, the part of the nervous system that controls muscles is functioning at minimum. This is a natural defense mechanism of the brain to keep the body from reacting to the content of neural activity. The brain activity during REM is like that of wakefulness.

Body movements (in general) occur about every 15 to 20 minutes, and repositioning about every 1-2 hours.