What Is REM Sleep and Why Is It Important?

The rapid eye movement (REM) sleep stage isn't just when the most vivid dreams occur; it also plays a major role in brain function and emotional regulation.

Every night, a healthy adult goes through four to six sleep cycles, each consisting of four stages – REM is the final one. Interestingly, it's when your brain activity is remarkably similar to when you're awake.

This article will guide you in understanding the REM sleep stage and why it matters to your sleep quality and overall health. It'll also give you tips for improving your REM sleep.

Key Takeaways

• REM sleep plays a significant role in enhancing brain health, memory, and emotional well-being.

• Adults need 90 to 120 minutes of REM sleep per night, which makes up about 20% to 25% of total sleep time.

• You can improve REM sleep by prioritizing good sleep hygiene habits and a healthy lifestyle.

Table of Contents

• What Is REM Sleep?

• What Happens During REM Sleep?

• When Does REM Sleep Happen?

• Why Is REM Sleep Important?

• How Much REM Sleep Do You Need?

• What if You Don’t Get Enough REM Sleep?

• How to Improve REM Sleep

• Conclusion

• Frequently Asked Questions About REM Sleep

What Is REM Sleep?

REM sleep is the fourth and final stage of a sleep cycle. While dreaming can happen in other sleep stages, the vivid ones you remember when you wake up occur during the REM sleep stage. Rapid eye movement sleep is important for brain development, emotional regulation and memory consolidation.

The term "rapid eye movement periods" was coined by researchers Eugene Aserinsky and Nathaniel Kleitman, who were studying infant sleep patterns in the 1950s. They observed "rapid, jerky" eye movements beneath the lids of sleeping babies. Later, it was formally classified as "stage REM" in a 1968 sleep-stage manual by Allan Rechtschaffen and Anthony Kales, according to an article published in Sleep.⁽¹⁾

What Happens During REM Sleep?

REM sleep lengthens and becomes more frequent as morning approaches. That's why it's often the sleep stage you wake up from. Physically, as its name suggests, your eye movements quicken. Your breathing, heart rate, and blood pressure become irregular, unlike in the deep sleep stage, where they are steadier, slower and lower.

It's also known as "paradoxical sleep" because brain waves become more active while the body is temporarily paralyzed. This paralyzed state, known as muscle atonia, can prove difficult for people with obstructive sleep apnea, a sleep disorder that's characterized by breathing pauses during sleep due to blocked airways. The paralysis also affects the muscle tone in your throat, making your airway more likely to collapse. On the other hand, some people experience REM sleep behavior disorder, where they're still able to move, causing them to punch, kick, scream or even just make small movements as their dream plays out.

Since this is the stage where vivid dreaming happens, it's also when nightmares can occur. The areas of your brain that process emotions (the amygdala), memories (the hippocampus) and sensory data (the visual cortex) are the most active. Meanwhile, the prefrontal cortex, which is responsible for logic, reasoning, and reality checking, takes a back seat. This combination sets the stage for intense and bizarre dreams.

Vivid dreaming also occurs because levels of the neurotransmitter acetylcholine increase, contributing to the hallucinatory quality of dreams and amplifying brain activity during REM sleep. Acetylcholine levels rise during REM sleep because the neurons that normally suppress its production become inactive. This frees the cells that release acetylcholine to fire strongly. On the other hand, neurons in the locus coeruleus, the brain's primary source of noradrenaline, are nearly silenced, reducing noradrenaline activity throughout the brain and suspending the logical thinking that characterizes dreaming.

You might also be wondering why your dreams feel so intensely visual and emotional during REM sleep. That's because your brain is consolidating the day's memories and emotions. These can make their way into your dreams.

When Does REM Sleep Happen?

REM sleep is the fourth (and final) stage of a sleep cycle, following three non-REM (NREM) sleep stages: NREM1 (transitional sleep), NREM2 (light sleep) and NREM3 (deep or slow-wave sleep).

You typically enter REM sleep for the first time about 90 minutes after you fall asleep and stay in it for about 10 minutes. One sleep cycle usually lasts for approximately 90 to 120 minutes. The REM sleep stage lengthens with every cycle. In fact, you might stay in the REM stage for as long as 45 minutes to an hour during your final sleep cycle.

Why Is REM Sleep Important?

REM sleep isn't just important because of dreaming. Your brain is also hard at work during this stage to improve cognition, process memories and regulate emotions. You need to spend enough time in it to ensure a good night's sleep.

Let's explore its benefits:

• It's good for brain development and function because it supports neuroplasticity, your brain's ability to restructure itself and form communication points (synapses) between nerve cells throughout your central nervous system. This process is important because it supports your ability to adapt your thinking and behavior to new experiences, information, and unexpected problems, even as you age.

• It helps process your emotions and regulate your mood. Think of REM sleep as your nighttime therapist, processing the day's emotions. Your brain's emotional center is very active during this sleep stage. It helps you separate emotion from memory. Put simply, this takes the sting out of painful memories, making them easier to face when you wake up.

• It improves your memory and problem-solving abilities. Your brain processes the memories from your day, selecting which to store in long-term memory during REM sleep. Unlike NREM3, which processes facts and events, REM sleep leans more toward procedural memory, such as mastering guitar chords or improving your pickleball serve. Ever had someone say to you, "Sleep on it," when faced with a problem? Well, the advice is spot on because REM sleep is where your brain thinks outside the box, coming up with creative solutions that you probably wouldn't think of while awake.

• It lowers your risk of dementia. A study published in Neurology found that for every 1% decrease in REM sleep percentage, the risk of incident dementia increased by 9% among participants.⁽²⁾ Remember that acetylcholine levels rise during REM sleep. Alzheimer's disease is characterized by a drop in acetylcholine-related nerve cells, making REM sleep vital to cognitive health.

How Much REM Sleep Do You Need?

REM sleep needs shift throughout life and vary from person to person. Newborns spend about 50% of their total sleep time in REM sleep (also known as "active sleep") because it's crucial for brain development. REM sleep decreases to about 30% to 35% during toddlerhood, then further declines to 20% to 25% in school-aged children.

As an adult (between the ages of 18 and 65), you need to spend approximately 20% to 25% of your total sleep time in REM sleep. If you're getting 7 to 9 hours of sleep per night, you should be spending 90 to 120 minutes in REM sleep across multiple sleep cycles.

In general, sleep changes with age. For older adults, REM sleep declines to 15% to 20% of total sleep time because sleep architecture shifts with age. Older adults are also more prone to fragmented sleep and spend less time in deep sleep.

What if You Don’t Get Enough REM Sleep?

Insufficient REM sleep can impact your health in several ways.

• The first is cognitive impairment, because your brain can't properly consolidate memories and move them into long-term storage. As a result, you're unable to retain information you picked up during the day. You might find yourself struggling with a new skill or brain fog when trying to understand new concepts.

• Physically, you might experience extreme daytime sleepiness, difficulty concentrating and slower reaction times, making you more prone to accidents.

• You might also find the simplest tasks difficult because your problem-solving skills take a nosedive due to a lack of REM sleep. You'll find solving problems that require creative thinking, recognizing patterns and connecting the dots extra challenging.

• Your mood takes a beating from insufficient REM sleep, too, because your brain was unable to process emotions adequately the night before. You might find yourself feeling irritable over the smallest things. Your emotional reactions might become intense, and your ability to keep them in check may decline. You might be less attuned to other people's emotions as well.

• Insufficient REM sleep is also linked to anxiety and vice versa, creating a vicious cycle. Anxiety can make falling asleep difficult, resulting in less time cycling through the sleep stages, including REM sleep periods. Remember that REM sleep helps your brain cushion you against yesterday's stressful memories when you wake up. A lack of it may make emotions difficult to handle, resulting in anxiety.

• Missing out on those final REM cycles typically means you are cutting your overall sleep time short. Chronic sleep deprivation can lead to a hormonal imbalance affecting appetite and stress levels, weaken your immune system, and slow your recovery when you're sick.

While this all might sound alarming, it's entirely possible to improve your REM sleep quality.

How to Improve REM Sleep

Improving REM sleep is more about focusing on all sleep stages instead of singling it out. Here are a couple of strategies to try:

• Get enough sleep every night, and that means 7 to 9 hours of total sleep time to ensure you spend enough time in the REM sleep stage and go through several sleep cycles.

• Stick to a consistent sleep schedule by going to bed and waking up at the same time every day. This regulates your circadian rhythm and strengthens your sleep architecture, so you move through sleep cycles efficiently and spend enough time in REM sleep.

• Make sure your bedroom is optimized for sleep. Keep your sleep space cool. The ideal sleeping temperature is 60 to 67 degrees Fahrenheit. Light is the enemy of sleep (including blue light from your gadget screens), so keep it at bay with an excellent sleep mask. Noise pollution can also disrupt REM sleep. Block environmental noise with earplugs or a white noise machine.

• Manage stress and anxiety to support sleep onset. Relaxing activities can help calm racing thoughts and tension. Pick up a book from the reading pile that's been accumulating on your nightstand. Meditate or do yoga to ease tense muscles and calm down. Try progressive muscle relaxation or gentle stretches. You can also journal your anxiety away by putting it on paper.

• Avoid caffeine, nicotine and alcohol before going to bed. Caffeine and nicotine are stimulants, which will keep you up. Alcohol can mess with your sleep patterns and cause multiple nighttime awakenings, disrupting REM sleep.

• Get your daily dose of exercise because it can enhance REM sleep and overall sleep quality. Just make sure to exercise at least 3 to 4 hours before bedtime, or you might have a hard time falling asleep.

• Maintain a healthy diet. Avoid heavy meals made up of fatty, spicy or sugar-laden foods. Know what to eat and not to eat before bedtime if you need a light midnight snack, such as Greek yogurt, almonds or whole grain crackers (throw in some hummus if you want something more substantial).

Conclusion

We hope this blog post helped you understand REM sleep and why it matters. From supporting your ability to adapt and learn to processing emotions to helping you wake up ready to tackle problems, this sleep stage does some pretty impressive heavy lifting while you're in dreamland.

Insufficient REM sleep can wreak havoc on your day-to-day life, making it hard to achieve peak performance and get things done efficiently. The great news is that you can improve REM sleep by prioritizing sleep quality and living a healthy lifestyle. Your brain will reward you with sharper thinking, better moods, and maybe even interesting dreams.

Frequently Asked Questions About REM Sleep

What Is the Difference Between REM and Non-REM Sleep?

Several factors differentiate REM sleep from non-REM sleep. REM sleep is a single sleep stage that supports emotional processing, memory consolidation, and creative problem-solving. Meanwhile, non-REM sleep consists of 3 stages that not only help consolidate facts, but also focus heavily on physical restoration, repairing tissues, building muscle and strengthening your immune system.

In a nutshell, non-REM does the heavy lifting to keep your body healthy and strong (while organizing your daily facts!), while REM keeps your mind sharp, creative, and emotionally balanced.

Why Do Your Eyes Move During REM Sleep?

While the jury is still out on why your eyes move during REM sleep, these movements are linked to the intense brain activity and vivid dreaming that happen during this stage. Whether your eyes are literally watching your dreams or responding to your brain's visual processing centers, the rapid movements are a sign that your brain is hard at work.

Is REM Sleep More Important Than Deep Sleep?

Neither is more important than the other because sleep needs vary from person to person. It depends on the circumstances. For instance, if you're recovering from illness or injury, your body might prioritize deep sleep. If you're stressed or learning something new, REM sleep is essential for emotional regulation and memory consolidation.

The important thing is to give your body enough time and the right conditions for sleep so that it can spend the appropriate amount of time in each stage.

Do You Only Dream in REM Sleep?

No, you don't only dream in REM sleep. You can dream at any stage of sleep. The difference is that dreaming during the REM sleep stage is usually more vivid and emotionally-charged, something you’ll recall in the morning.

Sources:  

(1) "Who discovered REM sleep?” Sleep, academic.oup.com/sleep/article/47/1/zsad232/7259816. Accessed 24 March 2026.

(2)“Sleep architecture and the risk of incident dementia in the community.” Neurology, www.neurology.org/doi/10.1212/WNL.0000000000004373, Accessed 24 March 2026.

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