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REM (Rapid Eye Movement) sleep is when your brain processes memories, regulates emotions, and fuels vivid dreams. But how much do you need, and what happens if you don’t get enough? Read on to find out.
7 Min Read | By Nat Took
Last Modified 17 March 2025 First Added 6 August 2021
Review for Accuracy by Dr Jason Ellis
Sleep isn’t just a time for rest; it’s when your body and brain get to work. In fact, you go through various stages of sleep at night. It’s quite an intense process as your body repairs itself, your brain consolidates memories, and essential hormones are regulated. During these cycles, you’ll go through NREM (non-rapid eye movement) and REM (rapid eye movement) sleep.
In this post, we’ll take a look at REM sleep, how much you need, and why it’s important for your health.
REM sleep stands for rapid eye movement and is the fourth and final stage of a full sleep cycle. During this stage, brain activity increases, eye movement becomes more rapid, and dreams tend to be vivid and intense. REM sleep plays a crucial role in various cognitive functions, such as memory consolidation and emotional processing, which we will cover later in this article.
Verified by Sleep Expert Sammy Margo
"REM sleep plays a huge role in memory, emotional processing, and brain function. Without enough of it, you might feel more forgetful, moody, or mentally drained. It’s an essential part of sleep that helps keep both your mind and body in check."
You may not be able to tell if you’re in REM sleep (as you’re asleep at the time!), but you can tell if someone else is in a REM sleep stage. Signs of REM include:
Less visible signs of REM sleep happening are:
In total, an adult needs around 90 minutes of REM sleep per night. This should make up 20–25% of a typical 7–9 hours of sleep. However, the amount of REM sleep we get depends on the quality of our rest as well as the total duration of our sleep.
Infants and children require more REM sleep than adults, with around 50% of their total sleep time spent in this stage. This is because REM sleep plays a crucial role in brain development and restoration, which are essential for growth.
REM sleep typically occurs about 90 minutes after you fall asleep. Each night, you go through 4–6 sleep cycles, alternating between REM and NREM sleep. Your first REM period usually lasts around 10 minutes, with each subsequent stage getting longer. The final REM stage can last up to an hour.
Learn more about what sleep consists of.
REM sleep is a key sleep stage essential for learning, memory, emotional regulation, and supporting the central nervous system. Let’s examine the benefits of REM sleep in more detail:
Studies suggest that a lack of REM sleep can lead to memory issues, affecting both the formation of memories from the previous day and the ability to learn new skills the following day. One study found that just four days of insufficient REM sleep affected cell proliferation in the part of the brain responsible for long-term memory in rats.
REM sleep is believed to play a crucial role in brain development, particularly in infants. One study suggests that REM sleep provides the neural stimulation necessary for the formation of mature neural connections.
As research into sleep progresses, scientists have discovered its vital role in emotional processing. Sleep deprivation, in general, can make us more sensitive to emotional stimuli, reducing our ability to cope with everyday stressors.
Studies have found a significant link between REM sleep and emotional regulation. Both the amount of time spent in REM sleep and REM latency (the time it takes to reach REM sleep) have been correlated with difficulties in emotional regulation, including impaired behavioural control and difficulty recognising emotions.
Some researchers theorise that REM sleep may help the brain prepare for wakefulness. It has been suggested that REM sleep becomes more prolonged as the night progresses to help transition the brain into a more alert and wakeful state.
Sleep deprivation, in general, can make it harder to carry out daily tasks, leaving us feeling groggy and less able to make decisions or process emotions. However, a lack of REM sleep can negatively affect overall health. Research has linked insufficient REM sleep to:
Since we can’t control what happens when we sleep, we can’t improve just our REM sleep in isolation. Enhancing this stage of rest requires a holistic approach – improving overall sleep quality, which benefits all sleep stages throughout the night. Here are some tips to help you do this…
Getting the advised 7-9 hours of sleep ensures enough time for your brain to go through a sufficient amount of sleep cycles for both mental and physical restoration. More sleep cycles equals more REM sleep phases, helping you feel more alert and ready to take on the day. It’s also important to reduce waking during the night.
Not sure how much sleep you need? Try our Sleep Cycle Calculator to find your ideal bedtime.
Having a good bedtime routine, which prepares your mind and body for rest, can help your overall sleep and, therefore, your REM sleep. Following the same relaxing and familiar steps each night signals your body that it’s time for rest, helping your mind shut off and fall into a restful sleep.
Ensuring your sleep environment is comfortable can help you sleep through the night and get the recommended amount of REM sleep. Set your room to a comfortable temperature, use blackout blinds or an eye mask if there are bright lights outside, and wear earplugs in noisy areas to minimise disruptions.
One of the best ways to improve your REM sleep is to avoid alcohol before bed. Alcohol may help you fall asleep quicker, but it can negatively affect the quality of your sleep. Studies show that alcohol intake both increases REM latency and suppresses REM sleep, especially in the first half of the night.
The best way to improve your REM sleep is to simply get enough quality sleep. Your slumber is important for your well-being, so don’t let it slip and try to ensure you’re getting enough. For comprehensive tips on improving your shut-eye, read our guide on how to sleep better at night.
More REM sleep isn’t necessarily the key to better sleep. In fact, too much REM sleep can leave you feeling fatigued the next day. Spending an unusually long time in the REM stage may indicate sleep deprivation and is also closely linked to depression. One sleep study found that REM sleep occurs more quickly and lasts longer than normal in people with depression. If you’re experiencing unrefreshing sleep and low mood, reaching out to your GP to explore treatment options is important.
While both REM sleep and deep sleep are equally important for restoration and essential body processes, they serve different roles. Deep sleep, also known as slow-wave sleep, is a stage of NREM sleep responsible for physical recovery, tissue repair, and immune system maintenance. During this stage, muscles relax, and brain activity slows down. In contrast, REM sleep is when the brain becomes more active, consolidating memories and processing emotions.
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