In this ongoing blog series, I’ve been exploring the five stages of sleep in some detail. Today, we’ll finish up the series with Rapid Eye Movement, or REM sleep—the stage where most dreams take place. REM sleep is characterized by (you guessed it) quick, sharp eye movements under the closed eyelids combined with a lack of muscle tone that prevents normal sleepers from acting out their dreams.
REM in Sleep Cycles
In REM sleep, the brain’s waves look almost characteristic of waking brainwaves, with alpha and beta brainwave activity (the highest frequency and shortest amplitude brainwaves). Alpha and beta brainwaves both occur during waking brain function, in a more desynchronous pattern than most sleep waves.
In the early cycles through the sleep stages, soon after dropping off to sleep, the brain spends more time in stages 3 and 4 and less time in REM sleep. As the night progresses, if sleep is uninterrupted, the body will spend more and more time in a state of atonia as the brain spends more time in REM sleep at the end of each stage. Getting a full night’s sleep ensures that you’ll be able to spend adequate time in REM sleep, which is important in maximizing your daytime alertness and function.
Why Is REM Sleep Important?
REM sleep helps us work through our daytime emotions and process experiences through our dreams. The exact reasons for REM sleep are unknown, but we do know that a lack of REM sleep impairs daytime ability to learn and function normally.
REM sleep disorder is a neurobiological problem in which the body doesn’t enter atonia when the brain shifts into REM sleep and begins to dream, with the result that the dreamer acts out his or her dreams—sometimes moving violently and risking injury. Recent research reported in Science Daily found that REM sleep disorder is closely linked to Parkinson’s Disease, with 60 to 80 percent of patients with REM sleep disorder developing Parkinson’s later in life.
Making the Most of REM Sleep
The fifth and most unusual sleep stage, REM sleep, thus has a significant impact on our waking lives and health. The best way to encourage healthy REM sleep is to get a full night’s sleep each night that lasts a multiple of 90 minutes. Seven and a half or nine hours is my usual recommendation—though every person’s sleep stages vary in length and you’ll have to experiment to find what sleep duration leaves you waking the most refreshed.