WEEKLY NEWSLETTER
Health's Top Stories
Get a weekly look at the most popular stories on Health.com.
Stages of sleep
content provided by
Healthwise
Sleep stages are divided into non–rapid eye movement (non-REM) and rapid eye movement (REM).
Non-REM sleep
Non–rapid eye movement (non-REM) sleep has four stages:
- Stages 1 and 2 are light sleep in which breathing is slower than when a person is awake.
- Stages 3 and 4 are called slow-wave (delta) sleep, in which the person's rate of breathing slows down further.
REM sleep
Rapid eye movement sleep is deeper than non-REM sleep. During REM sleep:
- The eyes and eyelids flutter.
- Breathing becomes irregular. During REM sleep, it is normal to have short episodes when breathing stops (apnea).
During sleep, a person usually progresses through the four stages of non-REM sleep before entering REM sleep. This takes about 60 to 90 minutes after falling asleep. The cycle is repeated three to four times each night with more time spent in the REM sleep stage and less time in sleep stages 3 and 4.
Last Updated:
July 13, 2007- Author:
- Maria G. Essig, MS, ELS
- Medical Review:
- Caroline S. Rhoads, MD - Internal Medicine
Jan Ulfberg, MD, PhD - Sleep Disorders
© 1995-2009 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
