A night of changing sleep stages
Follow a schematic night through non-REM and REM sleep.
The picture in words
- N1 and N2
- Non-REM sleep includes lighter stages.
- N3
- Deep sleep is more common early in the night.
- REM
- REM periods tend to lengthen later.
Reading the illustration
Read from left to right. The pattern is illustrative; stage timing varies between people and nights.
Try a question
What changes between the early and late parts of the illustrated night?
Show the explanation
The early part includes more N3 deep sleep; later periods include more REM. A recorded night can have a different pattern.
Read the sources
- National Heart, Lung, and Blood Institute. (2022a, March 24). How sleep works: Sleep phases and stages. https://www.nhlbi.nih.gov/health/sleep/stages-of-sleepSelected rendered passages: non-REM stages and changes across the night.