Briefly, sleep is divided into REM and NREM phases.
The NREM phase occurs first and is an outside periods of REM sleep phase.
It is characterized as a very important phase because for the full development of the body, this is because it is there that the release of growth hormones and the recovery of physical energy during the day occurs. The body achieves deep rest to the point of decreasing neural activity.
NREM sleep is dreamless sleep consisting of stages 1-3(previously stage 1 through 4) and characterized by a decrease of mental activity. a state that lacks the visible rapid eye movements and twitches(REM sleep) , and exhibiting a different EEG( electroencephalographic) pattern than REM sleep. Here the sleeper is still,breathing,brain waves and heart rate is slow, and blood pressure is low.
