Concept
Version 17
Created by Boundless
Stages of Sleep
A typical night's sleep
This sample hypnogram (EEG of sleep) shows how the proportion of the sleep cycle spent in REM sleep increases with each subsequent cycle over the course of a night. (Note that stages 3 and 4 are now considered to be one stage, stage 3.)
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"605px-Sleep_Hypnogram.svg.png."
https://en.wikipedia.org/wiki/File:Sleep_Hypnogram.svg
Wikipedia
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