The average person sleeps between 6.5 and 8.5 hours per day (or night, depending on your activity cycle.)

Stages of Sleep

Six stages of sleep have been identified. Each stage is associated with a distinct brain wave pattern.

Stage 0: Pre-Sleep

The pre-sleep stage is associated with alpha waves.

NREM: Non-R.E.M Sleep

Stage 1

Stage 2

Stage 3

Stage 4

R.E.M. : Rapid-Eye Movement

Most dreams occur during the REM stage of sleep.

Sleep Paralysis

Sleep paralysis is the paralysis of skeletal muscles which prevent a sleeper from acting out a dream. It was noted by Sigmund Freud in 1895.

Sleep Disorders

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See Also

• Brain Wave
• Dream
• EEG