During sleep, the brain moves through four different stages. One of these stages is rapid eye movement (REM) sleep. During this phase, the eyes move rapidly in various directions. Show
People typically enter REM sleep within the first 90 minutes of falling asleep. As the sleep cycle repeats, REM sleep occurs several times while a person is resting. In fact, it accounts for approximately 20–25% of an adult’s sleep cycle and over 50% of an infant’s. Most dreams occur during REM sleep. This is a stage that may play a role in learning, memory, and mood. This article covers REM sleep in more detail, including its stages, functions, and more. Share on PinterestRetno Ayu Adiati/EyeEm/Getty Images REM sleep typically starts within 90 minutes of a person falling asleep, and it cycles around every 90 minutes. During REM sleep, the body and brain go through several changes, including: Most people experience a state of temporary paralysis as the brain signals the spinal cord to cease the movement of the arms and legs. This lack of muscle activity is known as atonia, and it may be a protective mechanism to prevent injury that may result from “acting out” our dreams. During REM sleep, people may experience vivid dreams due to the increase in brain activity. Before entering the REM sleep phase, the body goes through each of the stages of non-REM sleep. The sections below look at each of these in more detail. Stage 1 non-REM sleepA person in this stage is between being awake and asleep or is in a state of very light sleep. Stage 2 non-REM sleepA slightly deeper sleep characterizes this stage. Body temperature drops, and heart rate slows down. Most people spend around half of their total sleep time in this stage. Stages 3 non-REM sleepStage 3 non-REM sleep is a state of deep and restorative sleep known as slow-wave sleep or delta sleep. The muscles relax, the supply of blood to the muscles increases, and the body repairs and grows tissue. REM sleepPeople enter the REM sleep phase following the above stages. This is the stage of sleep during which most people dream, though this may also happen in non-REM sleep. REM sleep may benefit learning, memory, and mood. A lack of REM sleep may have adverse implications for physical and mental health. Learning and memoryThe brain processes information and consolidates memories during sleep. As a result, sleep deprivation can negatively affect a person’s working memory. A 2016 study involving healthy adolescents also found that sleep deprivation could increase the risk of forming false memories. According to some studies, even short periods of daytime sleep can help a person learn muscle patterns (motor memory) and commit them to memory. Central nervous system developmentREM sleep may be essential for brain development in infants. Some research indicates that this sleep stage is responsible for the neural stimulation necessary for mature brain structure developments. These findings may help explain why infants require higher levels of REM sleep, with the number of minutes of REM sleep falling as people age. Consequences of a lack of REM sleepSome studies link a lack of REM sleep to:
Drinking alcohol before sleep can disrupt a person’s sleep cycle and sleep quality. Research is conflicting on how exactly alcohol affects REM sleep. Several studies report that alcohol intoxication does not reduce overall REM sleep but does reduce overall sleep quality. However, a further review of historic sleep research found several instances in which the duration and quality of REM sleep were lower following alcohol intoxication. Alcohol affects sleep in other ways, too. For example, it contributes to sleep apnea and snoring, causes an increase in bathroom visits, and interrupts the body’s circadian rhythm, which is the internal clock that regulates sleep and wake times. Some people experience REM sleep behavior disorder (RBD). This is a condition wherein the muscle paralysis a person usually experiences during REM sleep does not occur. It causes the person to act out vivid dreams. For example, they may kick, yell, or flail their arms. The onset of RBD tends to be gradual, with symptoms worsening over time. RBD results from malfunctioning nerve pathways in the brain. Some risk factors for its development include:
Treatment for RBD includes medication and changing the sleep environment to increase safety for the person with the condition and their sleeping partner. There are several ways to enhance both REM and non-REM sleep to reap the benefits of high quality sleep. The following tips may help improve REM sleep. Get enough sleepA healthy adult requires at least 7 hours of sleep per 24-hour period. Sleeping less than this reduces the number of REM sleep phases the person experiences. Address medical conditionsCertain medical conditions, such as sleep apnea, can affect sleep quality and impact REM sleep. Addressing these conditions may help improve the overall quality of sleep. Avoid alcohol before bedtimeAs moderate-to-high levels of alcohol intake before bed can reduce the number of REM sleep phases and delay entering the first REM phase, it is advisable to avoid alcohol consumption in the hours immediately before bed. Get 21 tips to fall asleep quickly here. Following the same bedtime routine each day prepares the body and mind for sleep. Having a regular bedtime routine may help maximize the amount of time asleep, potentially increasing the number of REM sleep phases a person experiences. Some good sleep habits include:
REM sleep is the stage in which most people vividly dream. These periods of sleep typically start around 90 minutes after someone falls asleep and cycle every subsequent 90 minutes. REM sleep is important to the consolidation of information and the development of memories. Research has linked disruptions in REM sleep with an increased chance of obesity and risk of migraine. Developing good sleep habits and having a consistent pre-sleep routine can help people improve the quality of their REM sleep and the quality of their overall rest time.
You may think nothing is happening when you sleep. But parts of your brain are quite active during sleep. And enough sleep (or lack of it) affects your physical and mental health. When you sleep, your body has a chance to rest and restore energy. A good night’s sleep can help you cope with stress, solve problems or recover from illness. Not getting enough sleep can lead to many health concerns, affecting how you think and feel. During the night, you cycle through two types of sleep: non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep. Your brain and body act differently during these different phases. What happens in the brain during sleep?Researchers continue to study sleep and its effect on us. While we’ve learned a lot about sleep, there’s still much that’s unknown. We know that brain chemicals are very involved in our sleep cycle. Neurotransmitters are chemicals that help the nerves communicate. They control whether we’re awake or asleep, depending on which neurons (nerve cells) they’re acting on:
Why do we need sleep?Sleep helps us in many ways. We need it for:
What are the stages of sleep?When you sleep, your brain goes through natural cycles of activity. There are four total stages of sleep, divided into two phases:
As you sleep, your body cycles through non-REM and REM sleep. You usually start the sleep cycle with stage 1 of non-REM sleep. You pass through the other stages of non-REM sleep, followed by a short period of REM sleep. Then the cycle begins again at stage 1. A full sleep cycle takes about 90 to 110 minutes. Your first REM period is short. As the night goes on, you’ll have longer REM sleep and less deep sleep. What is non-REM sleep?Three stages make up non-REM sleep. Stage 1: This stage of light sleeping lasts for five to 10 minutes.
Stage 2:
Stages 3
What happens during non-REM sleep?During non-REM stages, your body:
As you age, you get less non-REM sleep. Older adults get less deep sleep than younger people. What is REM sleep?When you enter REM sleep, brain activity increases again, meaning sleep is not as deep. The activity levels are like when you’re awake. That’s why REM sleep is the stage where you’ll have intense dreams. At the same time, major muscles that you normally control (such as arms and legs) can’t move. In effect, they become temporarily paralyzed. Usually, REM sleep arrives about an hour and a half after you go to sleep. The first REM period lasts about 10 minutes. Each REM stage that follows gets longer and longer. The amount of REM sleep you experience changes as you age. The percentage of REM sleep:
What else happens to the body in REM sleep?Besides increased brain activity and muscle relaxation, your body goes through a series of changes during REM sleep. These changes include:
What affects sleep quality?Chemical signals in the brain influence our sleep and wake cycles. Anything that shifts the balance of these neurotransmitters can make us feel drowsier or more awake. For example:
How much sleep do I need?Many factors affect how much sleep you need. Age is a big factor:
What is a sleep debt?If you haven’t slept well or long enough for a few days, you might create a sleep debt. Once your debt builds up, you may feel physically and mentally exhausted. Try to make sure you get enough sleep every night to avoid creating this debt. You can’t necessarily make up your debt by sleeping a lot on the weekends. It’s best to get enough sleep all week long. Can we adapt to needing less sleep?Generally, people don’t adapt to getting less sleep than they need. You may feel like you’re used to reduced sleep, but it still affects your function. For example, it can harm your judgment and reaction time. What is sleep deprivation?When you’re sleep deprived, you’re not getting the total amount of sleep you need. Signs of sleep deprivation include:
What are sleep disorders?According to the American Sleep Association, at least 40 million Americans experience sleep disorders each year. Another 20 million have occasional sleep issues. These disorders cause sleep deprivation, leading to problems with work, school, driving and social activities. There are more than 70 sleep disorders. A few, known as disruptive sleep disorders, lead to moving around or making sounds. Other sleep disorders involve food. And some sleep disorders overlap with psychiatric conditions. If you have problems with sleep or feel very tired, talk to your healthcare provider about a possible sleep disorder. Some of the most common sleep disorders include:
What are good sleep habits?Good sleep habits, also called good sleep hygiene, are practices to help you get enough quality sleep. Do:
Don’t:
A note from Cleveland Clinic Far from being a state of doing nothing, sleep is an essential part of our lives. It helps our body rest, recharge and repair. There are four sleep stages — three in the non-REM phase plus REM sleep. Many factors can affect sleep quality, including the food and drink you consume before bed and room temperature. Many people experience trouble sleeping now and then. But if you think you may have a sleep disorder, talk to your healthcare provider. Common sleep disorders include insomnia (trouble falling asleep) and sleep apnea (breathing trouble during sleep). Your provider can help you get the diagnosis and treatment you need. |