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What Is REM Sleep?
Rapid eye movement (REM) sleep, also known as paradoxical sleep (PS) or desynchronized sleep, is a sleep stage that happens shortly after falling asleep where most dreaming takes place. REM sleep occurs in mammals and birds and is characterized by an elevated heart rate, rapid eye movement, fluctuations in blood pressure, and temporary paralysis in the arms and legs (to prevent you from moving around while you dream). REM sleep occurs as part of our circadian rhythm, the internal biological clock that regulates our sleep-wake cycle and affects our metabolism, body temperature, and hormonal releases.
Why Is REM Sleep Important?
REM sleep affects your mood, memory, and learning efficiency. Getting enough REM sleep can improve recall and memory consolidation and help your brain regulate the synapses associated with some types of motor learning. The ontogenetic hypothesis claims that neuron activity involved in the REM sleep cycle stimulates the developing brains of newborns, helping them form mature synaptic connections. While scientists are uncertain about the exact reason for dreaming, they speculate that it is how our brain’s process emotions.
Where Does REM Sleep Fit in the Sleep Cycle?
REM sleep occurs approximately 90 minutes after falling asleep. While it is technically the last stage of the sleep cycle, the body repeats the whole cycle around four to six times per night. REM sleep alternates with the three other stages of non-REM (or NREM) sleep: dozing off, light sleep, and deep sleep, also known as slow-wave sleep (SWS). Though dreaming can occur in different sleep phases, REM sleep is where our most vivid dreams are produced. REM sleep produces brain activity levels similar to those in an awakened state. REM sleep cycles get longer as the night progresses and make up around 25 percent of our total sleep.
What Are the Effects of Diminished REM Sleep?
Sleep deprivation as a whole can affect your body’s wellbeing, but a diminished REM sleep can cause psychological disturbances like anxiety, aggression, irritability, and hallucinations. A reduction in REM sleep can also lead to difficulty concentrating, with those experiencing a restful night sleep having better memory retention and recall. People with REM sleep behavior disorder are at higher risk of developing other neurological disorders like sleep apnea, narcolepsy, and Parkinson’s Disease.
3 Tips for Better REM Sleep
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According to the National Institutes of Health (NIH), the human body cycles through the three stages of sleep around four to six times per night. For tips on how to improve the REM stage of sleep, see below:
- Create a sleep schedule. Creating a schedule for your sleep times can help your body get into the habit of “normal sleep.” Discontinue the use of bright screens or stimulating electronics an hour before bedtime can help your body prepare for sleep. Bright light can confuse your inner clock into thinking it’s daytime, which can cause your body to secrete less melatonin, resulting in less sleepiness at bedtime.
- Exercise. Routine exercise can help your body expend its excess energy, which can improve the quality of your sleep at night. The later you go to sleep, the lighter and more REM-heavy your sleep will be. While REM sleep is a necessary part of the sleep cycle, getting too much without a balance of deep sleep can leave you feeling groggy the next day.
- Watch when you drink. Drinking a lot of fluids before bed can increase the frequency of late-night bathroom visits. Too many interruptions while sleeping can decrease overall sleep REM sleep, which can affect your cognitive functions. Additionally, drinking alcohol before bed can also be unhelpful. While drinking may cause sleepiness, it can suppress the quality of REM sleep.
What Is the Difference Between REM and Non-REM Sleep?
The main difference between REM and non-REM comes down to brain activity. While REM sleep is characterized by rapid eye movements and high brain activity levels, non-REM sleep is when our brains start to slip into a more restful state. Brain waves are slower, muscles relax, and the body enters a light sleep.
NREM sleep also includes a deep sleep stage, where the heartbeat and breathing slow, and internal temperature drops. While each stage is important for quality sleep, rapid eye movement sleep is more similar to stages of wakefulness, whereas non-REM sleep is when the body and brain are more at rest.
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