What Does REM Stand For?

Medically reviewed by
 Dr. Colleen Ehrnstrom, Ph.D., ABPP

Dr. Colleen Ehrnstrom, Ph.D., ABPP

Colleen Ehrnstrom, Ph.D., ABPP, is a licensed clinical psychologist who specializes in acceptance and commitment therapy (ACT). She is board certified in cognitive behavioral therapy (CBT) and works in counseling and psychiatric services (CAPS) at the University of Colorado at Boulder.

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Last Updated On October 6th, 2023
What Does REM Stand For?

Key Takeaways

  • REM Sleep is Essential: REM (Rapid Eye Movement) sleep is a crucial stage of the sleep cycle where your brain is as active as it is when you’re awake. It is characterized by rapid eye movements, increased brain activity, and vivid dreams. This stage helps consolidate memories, enhances learning, and plays a vital role in your overall health.
  • Sleep Cycles: REM sleep is part of the sleep cycle, which typically consists of four stages of NREM (Non-Rapid Eye Movement) sleep followed by REM sleep. Each sleep cycle lasts 90 to 120 minutes, and a healthy adult should experience four to five such cycles during a night’s sleep, totaling 7-8 hours.
  • Consequences of REM Sleep Deprivation: Lack of REM sleep can lead to negative health consequences, including difficulties with memory, concentration, and coping with stress. It has also been associated with an increased risk of migraines and obesity. To improve REM sleep, maintain good sleep hygiene practices, such as going to bed and waking up at consistent times and creating a comfortable sleep environment.

REM is the Rapid Eye Movement sleep stage when your brain is as active as it is during the awake state. Though you are sleeping and your eyes are closed, your eyes dart from side to side beneath your eyelids during REM sleep. This led to the name “Rapid Eye Movement (REM)” sleep.

In this article, we discuss the importance of REM sleep, the problems we may experience when it’s lacking, how we can improve REM sleep, and our overall sleeping experience.

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What is REM Sleep?

While sleeping we experience four stages of NREM sleep followed by the REM sleep stage. REM sleep, like all other sleep stages, is crucial to our health. It is usually experienced at the end of each sleep cycle. Each sleep cycle typically lasts for 90 to 120 minutes. Every healthy adult needs four to five such sleep cycles, adding up to 7-8 hours of sleep each night. Sleep deprivation causes a lack of concentration and daytime drowsiness, affecting our productivity the next morning.

You typically experience your first phase of REM sleep after 90 minutes of sleep. In the first sleep cycle, REM lasts for 10 minutes. Its duration increases with every sleep cycle, lasting up to an hour in the final cycle. Every healthy adult spends about 20 percent of their sleep time in REM sleep.

During REM sleep there’s an increase in brain activity that leads to dreams. If you wake up during the REM sleep stage, you typically remember your dreams clearly. Your brain waves oscillate very fast during this stage, mimicking an awake state.

While your brain is active, your body is in a state of paralysis called “atonia.” Your brain signals your spinal cord to limit the movement of your arms and legs, preventing you from acting out your dreams. Due to this contrast between the mind and the body, REM sleep is also called paradoxical sleep.

During the REM sleep stage, your body goes through several changes such as:

  • Fluttering eyelids
  • Irregular and fast breathing
  • Increase in heart rate and blood pressure
  • Changes in body temperature
  • Twitching of the face

Other Stages of Sleep

The REM sleep stage is preceded by three stages of Non-Rapid Eye Movement (NREM). During NREM sleep, your brainwaves are much slower than the REM sleep stage. In this section, we discuss the changes in body and brain during the three stages of NREM sleep and why they are critical for a good night’s sleep.

  • NREM Stage 1 (N1 Sleep): This stage lasts for 5 to 10 minutes as your eye movements and brain activity slow down. Your muscle tension reduces, helping your body relax.
  • NREM Stage 2 (N2 Sleep): This stage lasts for about 30 to 60 minutes, as your body temperature and heart rate drop. Your brain waves continue to slow down, further preparing your body for a deep sleep stage.
  • NREM Stage 3/4 (N3/4 Sleep): This stage lasts between 20 to 40 minutes after your blood pressure and respiratory rates drop. It is the deepest and most restorative phase of sleep. You are least likely to be disturbed by external stimuli during this sleep stage. During this stage of a deep sleep, your brain releases HGH (Human Growth Hormone) for muscle growth and regeneration.

Importance of REM Sleep

This fourth stage of sleep completes your sleep cycle. REM sleep stage consolidates your memories and improves your learning skills and coping mechanisms.

Influences Learning and Memory

When you sleep well, your memories are consolidated more effectively You can access them more easily thanks to the REM sleep stage. This explains why students are often told to get enough sleep, especially the night before their exams.

You may sit up late into the night trying to learn new concepts, but if you don’t get enough sleep, it may be difficult to remember the new concepts.

An American Academy of Sleep Medicine (AASM) study Verified Source American Academy of Sleep Medicine Society focused on sleep medicine and disorders, and the AASM is who authorizes U.S. sleep medicine facilities. View source on rats showed that depriving them of REM sleep for 4 days reduced cell proliferation in the forebrain. This process of cell proliferation contributes to long term memory.

Both NREM and REM sleep are equally important for learning and memory. NREM sleep familiarizes your brain with the new learnings and REM sleep consolidates them well in your long term memory.

Develops Young Brains

REM Sleep

Adults spend about 20 percent of total sleep time in the REM stage, while infants spend as much as 50 to 70 percent time in REM sleep. Studies show REM sleep makes experiences “stick” to young brains, crucial for their overall development. As your brain develops with age, the duration of REM sleep decreases. The total amount of time spent in REM sleep remains between 20 to 25 percent once you reach adulthood.

Strengthens Coping Mechanisms

When you sleep well, you are better equipped to cope with challenging situations. A well-rested person can think through situations to find solutions, in part because sleep deprivation impairs your ability to focus. According to a National Institute of Health study, Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source animals deprived of REM sleep showed poorer coping and defensive responses in threatening situations.

Consequences of Insufficient REM Sleep

Lack of REM sleep is linked to negative health consequences, such as migraines and obesity. To avoid these consequences, make sure you get at least 7-8 hours of sleep every night.

  • Migraines: A 2010 study found REM Sleep Deprivation (RSD) can increase chronic migraines. The levels of a certain protein associated with chronic pain increased during RSD, intensifying your migraine attack.
  • Obesity: Inadequate sleep increases the chances of obesity because it triggers the hunger hormone ghrelin. You tend to feel more hungry leading to overeating and obesity. An AASM study Verified Source American Academy of Sleep Medicine Society focused on sleep medicine and disorders, and the AASM is who authorizes U.S. sleep medicine facilities. View source conducted on children aged 7 to 17 linked reduced REM sleep to excess weight in children and adolescents.

Disorders in REM Sleep Stage

You may experience some sleep disorders, such as REM sleep behavior disorder or Obstructive Sleep Apnea (OSA) during REM sleep. These impact your overall sleep quality. To address these sleep disorders, we recommend consulting a doctor.

REM Sleep Behavior Disorder

Those affected with REM sleep Behavior Disorder (RBD) tend to act out their dreams. RBD leads to violent movements of arms and legs causing injury to self, or others sharing the bed with the sleeper.

During REM sleep, the body is usually in a state of paralysis called atonia, preventing movement of arms and legs. However, muscle atonia may get impaired due to the side effects of antidepressants or neurodegenerative diseases like Parkinson’s or dementia, hence triggering RBD. RBD is generally seen in men above 50, but sometimes children or women may experience it.


While OSA can occur during any sleep stage, the prevalence of REM OSA is higher Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source due to muscle atonia during REM. Your throat muscles are more prone to falling backward during REM sleep as your body experiences a state of muscle paralysis.

How to Improve REM Sleep

A calm mind, a supportive mattress, and a comfortable bedroom temperature are going to increase the success of a good night’s sleep. Lack of these factors may exacerbate sleep disruptions. Sleep disruptions reduce your total sleep time because if you go all the way back up to Stage 1 (and/or fully awake), the progression through NREM/REM starts over—and this can hinder your REM sleep.

Follow these sleep hygiene tips to eliminate disruptions and sleep well at a stretch for 7 to 8 hours.

  • Be consistent about going to bed and waking up around the same time every day (try to stay with 15-30 minutes)
  • Experiment with a hot water bath or shower at bedtime to see if this calms you (if it overheats you, discontinue)
  • Avoid caffeine past 12 pm
  • Avoid a spicy and heavy meal for dinner
  • Set bedroom temperature between 60 to 67 degrees
  • Use a comfortable mattress and pillow
  • Avoid blue light 1-2 hour before sleep (such as phones, e-readers, or TVs)


What does REM stand for?

REM stands for Rapid Eye Movement and REM sleep is the final stage of sleep in every sleep cycle. We usually need four to five sleep cycles throughout the night to feel well-rested. During REM sleep, your brain activity increases, your pulse quickens, and you have dreams. REM sleep helps to consolidate your memories. It also improves your coping mechanisms during challenging situations.

What is another name for REM sleep?

REM sleep is also called paradoxical sleep (PS) because of the contrast in your brain and body. While your brain mimics a wakeful state, your body is in a state of paralysis. Your brain signals the spinal cord to prevent movement of arms and legs during the REM sleep stage. This stops you from physically enacting your dreams.

Which is better REM or deep sleep?

Deep sleep is experienced during the third NREM sleep stage. Both REM and deep sleep are crucial for your mental and physical well-being. Your muscles repair and regrow during deep sleep stages, while your memory gets consolidated during REM sleep stage.  Waking up abruptly in either of these stages makes you feel irritable, groggy, and disoriented.

How much REM sleep should a person get?

An average healthy adult should get 1.5 to 2 hours of REM sleep, out of the total 7 to 8 hours of their nighttime sleep. REM sleep comprises 20 percent of your total sleep time. When you get sufficient REM and NREM sleep, you maximize the health benefits of sleep.

What happens if you don’t get REM sleep?

Your sleep is never complete without REM stage sleep. Lack of REM sleep increases the chances of obesity and migraines. It impairs your sleep quality, triggering the risk of cardiovascular disease, diabetes, obesity, and depression.


REM sleep comprises only 20 percent of your sleep, but it is as crucial as the NREM sleep stages. All four sleep stages work together to safeguard your health, boost your memory, improve your concentration, and better prepare you to face the challenges of the next day. Missing out on any of these stages can affect your mental and physical well-being.

About the author

Mitchell Tollsen is a graduate student and a freelance writer who’s contributed to the Early Bird blog for three years. Mitchell’s always been fascinated by the science of sleep and the restorative processes our bodies undergo when at rest. The self-titled “Sleep Expert” is always looking for ways to improve his shut-eye, and throughout the years has implemented numerous lifestyle changes and tried dozens of sleep-promoting gadgets to determine the best ways to truly get better rest.

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