Sleep Cycles
Sleep Stages
Waking | REM Sleep | NREM Sleep | ||||||||
Stage 0 | Stage R |
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Eyes open, responsive to external stimuli, can hold intelligible conversation | Brain waves similar to waking. Most vivid dreams happen in this stage. Body does not move. |
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16 to 18 hours per day | 90 to 120 min/night | 4 to 7 hours per night |