Why We Sleep
How Sleep Works
Sleep and You
Can't Sleep?
Bring Out the Stars
Games and Puzzles

Sleep Cycles
Nature is full of cycles.
As the Earth rotates we have cycles of sunlight and darkness.
The moon has cycles.
We also have cycles in our sleep. 
There are 5 stages in one sleep cycle.
Each sleep cycle takes about 90 minutes.
The sleep cycle is repeated 5 or 6 times during the night.

Find out more about how sleep works…
How Sleep Works
Learn more about how sleep works with this fun activity!
Snooze Clues


  •  why we sleep  •  how sleep works  •  sleep and you  •  can't sleep?  •  dreams  • 
•  bring out the stars  •  games and puzzles  •  parents and teachers  • 
•  home  •  about us  • 
National Sleep Foundation