The useful idea
- A daily clock
The internal circadian clock promotes sleep daily at night, when it is dark.
- Cycles repeat
Sleep occurs in repeating periods, during which the body alternates between two distinct modes: rapid eye movement sleep (REM) and non-REM sleep.
- Activity decreases
During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment.
Why this matters
Use Sleep to ask clearer questions; personal health decisions still belong with a qualified professional.
Try this
Use Sleep to ask clearer questions; personal health decisions still belong with a qualified professional.
Test your recall
Which idea belongs to the explanation of Sleep?
- Cycles repeat
- A daily clock — correct
- Activity decreases
The internal circadian clock promotes sleep daily at night, when it is dark.
General education only — not medical advice, diagnosis, or treatment.