Sleep researchers divide sleep into REM (rapid eye movement) and four stages of non-REM. Each of these stages has its own distinctive brain wave frequency.
The sleep cycle begins with Stage One non-REM sleep which is the nodding off period between sleeping and waking. During this stage, one may feel the sensation of falling into a hole. During Stage Two the brain slows and shows only a few bursts of activity. During State Three and Stage Four the brain shifts into slow-wave sleep in which heart and breathing rates drop dramatically.
The first period of REM sleep comes after 70 minutes of non-REM sleep. This first period of REM sleep lasts only about five minutes. During the sleep cycle, REM and non-REM alternate with the REM periods becoming longer and the non-REM becoming shorter. Just before waking, there is a forty-minute period of REM sleep.
When people are deprived of sleep, particularly REM sleep, dream intensity increases. Alcohol and nicotine both repress REM sleep. Anti-depressants also suppress REM sleep: take away dreams and depression lifts.
A typical person will spend about 27 years dreaming. Dying from a lack of REM sleep appears to be an urban myth and sleep researchers report that they have never seen this occur except in lab rats.
Dreaming helps us to assimilate memories.
Welcome to Street Prophet Saturday. This is not a dream, nor is it a nightmare. This is an open thread where we can talk about dreams, sleep, hopes, dinner, politics, pets, and religion.