Guest guest Posted October 8, 2004 Report Share Posted October 8, 2004 The Stages of Sleep There are five stages of sleep that cycle over and over again during a single night's rest: stages 1, 2, 3, 4 and REM (rapid eye movement). Stages 1 through 4 are also known as non-rapid eye movement sleep (NREM). About 50% of our sleeping time is spent in stage 2 and about 20% in REM. A complete sleep cycle, from the beginning of stage 1 to the end of REM usually takes about an hour and a half. An adult normally sleeps more than 2 hours a night in REM. Stage 1 is a light sleep during which the muscles begin to relax and a person can be easily awakened. During stage 2, brain activity slows down and eye movement stops. Stages 3 and 4 comprise deep sleep, during which all eye and muscle movement ceases. It can be difficult to wake a person during deep sleep. Stage 3 is characterized by very slow brain waves (delta waves), interspersed with small, quick waves. In stage 4, the brain waves are all delta waves. It is during deep sleep that some people sleepwalk and children may experience bedwetting. It is during REM sleep that people dream. The muscles of the body stiffen, the eyes move, the heart rate increases, breathing becomes more rapid and irregular, and the blood pressure rises. go here for more http://www.neurologychannel.com/sleepdisorders/ markb __________________________________________________ Quote Link to comment Share on other sites More sharing options...
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