Rapid eye movement, or REM sleep, is the final phase of the four stage cycle that occurs during sleep. Unlike non-REM sleep, the fourth phase is characterized by an increase in brain activity and autonomic nervous system functions which are closer to what is seen during the awakened state.
Key Takeaways: What Is REM Sleep?
REM sleep is an active stage of sleep characterized by increased brain wave activity, return to awake state autonomic functions, and dreams with associated paralysis.
- The brainstem, particularly the pons and midbrain, and the hypothalamus are key areas of the brain that control REM sleep with hormone secreting “REM-on-and-REM-off” cells.
Dreams and REM Sleep
The most vivid dreams occur during REM sleep, during which dreams are often elaborate and emotional experiences of imagined life, most often associated with sadness, anger, apprehension, or fear.
- A person can also more readily recall a dream when awakened from REM sleep rather than from non-REM sleep.
Benefits of REM Sleep
REM sleep is necessary for health and well-being, as mild sleep deprivation increases risk for chronic health conditions and severe sleep deprivation can lead to hallucinations or even death
- While non-REM sleep is required in order to survive, the benefits of REM sleep remain inconclusive
- Some drugs, including MAO antidepressants, lead to drastically decreased REM sleep
REM Definition
The three prior stages of sleep, known as non-REM, N1, N2, and N3, occur initially during the sleep cycle to progressively slow bodily functions and brain activity.
- REM sleep is the longest period of sleep and lasts for 70 to 120 minutes. The proportion time spent in this phase is determined by a person’s age.
Sources
Purves, Dale
- “Natural Patterns of Sleep”
- The Characteristics of Sleep | Healthy Sleep, 18 Dec. 2007
- http://healthysleep.med.harvard.edu/healthy/science/what/sleep-patterns-rem-nrem.html
REM and Your Brain
During REM sleep, brain wave activity measured on an electroencephalogram (EEG) also increases, as compared to the slower wave activity seen during non-REM sleep.
- The major brain regions that are activated during REM sleep include the brainstem, hypothalamus, pons and midbrain, the brain, and the hippocampus.
