Of all the sleep stages we cycle through hour after hour and night after night, REM sleep is probably the most \u201cfamous.\u201d Most people know that we do some of our best dreaming during REM sleep, but there\u2019s a lot more going on than meets the rapid-eye movement. <\/span>Dylan Petkus, M.D.<\/span><\/a>, says we can almost think of REM sleep as the \u201cbrain\u2019s night shift.\u201d In addition to being the sleep stage where our most vivid (and memorable) dreams occur, he says that memory consolidation, emotional balance, and brain development are all a part of the process. (<\/span>1<\/span><\/a>) (<\/span>2<\/span><\/a>) (<\/span>3<\/span><\/a>)<\/span><\/p>\n\n\n\n
Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn\u2019t be taken as medical advice, and it shouldn\u2019t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.<\/em><\/strong><\/p>\n\n\n\n\n\n\n\n REM sleep (or Rapid Eye Movement sleep) is a stage of sleep where your eyes move rapidly, and your brain activity is comparable to that of a waking state. People also experience their most vivid dreams during REM sleep, but our bodies are in a state of temporary paralysis to keep us from acting out those dreams thanks to our reticular activating system (RAS). (<\/span>4<\/span><\/a>) (<\/span>5<\/span><\/a>)<\/span><\/p>\n\n\n\n Most people understand<\/span> REM sleep to be the stage where dreaming occurs<\/span><\/a>. What many people don\u2019t know is that during REM sleep, our bodies are busy with a host of activities and functions.\u00a0<\/span><\/p>\n\n\n\n\n\n \u201cDuring REM sleep, your entire body is completely paralyzed except for your eyes, which rapidly move in different directions as you sleep \u2014 hence the name REM \u2014 and <\/span>thermoregulation<\/span><\/a>, your body\u2019s ability to control internal body temperature, is reduced,\u201d says <\/span>Dr. Dan Gartenberg<\/span><\/a>, sleep scientist and sleep health advisor for CPAP.com <\/span><\/p>\n\n\n\n Other physical goings-on during REM sleep include: <\/span><\/p>\n\n\n\n Sleep occurs in two phases: nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. These phases are further broken down into four stages that move from light to deep sleep: N1, N2, N3, and REM. With a full night's sleep, your body moves through these stages in<\/span> sleep cycles<\/span><\/a>. <\/span>Most people will go through four to six sleep cycles every night, each lasting about 90 minutes.<\/b> (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n N1 sleep <\/span><\/a>is the lightest stage of sleep when you drift off to sleep. Your body retains some muscle tone, and your breathing is regular. This stage can last anywhere from one to five minutes and accounts for 5 percent of your total sleep time. (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n This is a deeper sleep stage during which your heart rate and body temperature drop. Brain wave data reveals the presence of sleep spindles and K-complexes (or long delta waves) during <\/span>N2 sleep<\/span><\/a>, both of which play a key role in memory consolidation. (<\/span>7<\/span><\/a>) The first N2 stage of the night typically lasts somewhere around 25 minutes, and successive N2 stages lengthen as the night progresses. N2 sleep accounts for approximately 45 percent of your total sleep time. (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n Also known as slow-wave sleep (SWS), <\/span>N3 is the deepest stage of sleep<\/span><\/a>. It's also known as <\/span>deep sleep<\/span><\/a> or delta sleep because brain wave data reveals the presence of, you guessed it, delta waves. N3 is the sleep stage during which the body tackles bone and muscle building, releases hormones for growth and repair, and cytokines for immune strengthening. It's the most difficult sleep stage to awaken from and, as such, the one most commonly associated with <\/span>sleep inertia<\/span><\/a>. With age, people spend less time in N3 sleep, picking up more time in N2. (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n The fourth and final sleep stage is REM sleep. This stage is marked by erratic and irregular breathing rates, rising heart rates, and muscle atonia (reduced muscle tone that prevents us from acting out our dreams). (<\/span>7<\/span><\/a>) Brainwave activity reveals the presence of beta waves, which are remarkably similar to brainwave activity in a waking state. This is the stage where most dreaming occurs and is typically less restful than other sleep stages. (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n Sleepers typically hit their first REM sleep stage somewhere around 60 to 90 minutes into their sleep cycle. (<\/span>7<\/span><\/a>) Like N2, initial REM stages are short and progressively get longer as the night wears on. For this reason, most of our REM sleep occurs during the second half of the night. Initial REM stages can be as short as 10 minutes, while later REM stages can last up to one hour. (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n According to Petkus, REM sleep is vital for solidifying memories, enhancing learning, and supporting logical reasoning and decision-making. Ultimately, a lack of REM sleep has been linked to cognitive impairments and difficulties in these areas (<\/span>8<\/span><\/a>). <\/span><\/p>\n\n\n\n Memory and learning.<\/b> Petkus tells us, \u201cOne of the key roles of REM sleep is memory consolidation. It\u2019s like hitting the save button on your day\u2019s experiences and lessons, making sure they stick.\u201d And research corroborates as much, with studies showing that REM sleep enhances memory processing and retention, making it essential for learning new things. (<\/span>1<\/span><\/a>)<\/span><\/p>\n\n\n\n Emotional balance.<\/b> In terms of emotion regulation, Petkus says REM sleep is like \u201ca natural therapy session where your brain processes emotional memories and reduces the impact of fears.\u201d As a matter of fact, one recent study found that REM sleep has a protective quality, playing a key role in weakening the grip of fearful memories, making them less intense over time. (<\/span>2<\/span><\/a>)<\/span><\/p>\n\n\n\n Brain development.<\/b> Research shows that REM sleep plays a role in brain development. This makes it especially important for newborns, as it does some pretty heavy lifting to support the development of their central nervous system and the formation of mature neural connections. (<\/span>3<\/span><\/a>)<\/span><\/p>\n\n\n\n Physical health.<\/b> Insufficient REM sleep has been associated with increased oxidative stress (which can lead to cardiovascular issues like hypertension and heart disease) and disrupted immune function, leaving the body more susceptible to illnesses. (<\/span>9<\/span><\/a>)<\/span><\/p>\n\n\n\n Higher death rates. <\/b>Research suggests that improvements to REM sleep may reduce the risk of early death. One study from 2020 found that even something as small as a 5 percent reduction in REM sleep was associated with a 13 to 17 percent increase in mortality for middle-aged men and women and older men. (<\/span>10<\/span><\/a>)<\/span><\/p>\n\n\n\n According to Petkus, adults need about 1.5 to 2 hours of REM sleep each night, which roughly accounts for 20-25 percent of our total sleep time. (<\/span>7<\/span><\/a>) Explaining further, Petkus says we should think of our REM sleep time as an essential maintenance window for our brain \u2014 if we\u2019re not hitting this mark, it\u2019s like trying to run a computer that hasn\u2019t been updated in over a year. (<\/span>7<\/span><\/a>)<\/span><\/p>\n\n\n\n And while adults only spend about 25 percent of their sleep time in REM, infants need far more, as their cognitive development is in high gear. As such, babies spend approximately 50 percent of their total sleep time in REM sleep. As they mature, those high requirements for REM sleep begin to drop, eventually falling more in line with adult REM requirements. (<\/span>11<\/span><\/a>)<\/span><\/p>\n\n\n\n According to Gartenberg, \u201cPrioritizing sleep at night by having a consistent sleep schedule is one of the most effective ways to get a healthy amount of REM sleep.\u201d He adds that practicing <\/span>good sleep hygiene<\/span><\/a> can also help \u2014 more on that below. <\/span><\/p>\n\n\n\n Sleep research consistently shows that <\/span>sugar<\/span><\/a>, <\/span>caffeine<\/span><\/a>, and <\/span>alcohol<\/span><\/a> can have a detrimental impact on sleep duration and quality. For this reason, Gartenberg suggests cutting these sleep stealers from your diet. If that\u2019s not feasible, you could eliminate them in the late afternoon and evening so your REM sleep doesn\u2019t take a hit. We\u2019ll add here that heavy meals won\u2019t do you any favors either. (<\/span>12<\/span><\/a>)(<\/span>13<\/span><\/a>)<\/span><\/p>\n\n\n\n \u201cDecreasing (or eliminating) the amount of time spent on your devices before bed can also help you get enough REM sleep,\u201d says Gartenberg. \u201c<\/span>Blue light <\/span><\/a>deters the body from releasing melatonin (aka the sleep hormone), which helps your body wind down and get ready to fall asleep.\u201d If you're wondering what the trade-off is between sleep and your iPhone, one study found that reducing blue light can increase REM sleep by 13.9 minutes (<\/span>14<\/span><\/a>).<\/span><\/p>\n\n\n\n \u201cOther simple hacks to improve REM sleep include keeping an optimal sound, light, and temperature environment at night,\u201d says Gartenberg. Ideally, your bedroom should be dark, quiet, and cool. (<\/span>13<\/span><\/a>) <\/span><\/p>\n\n\n\n Sleep disorders and REM sleep share an interesting relationship. In some cases, certain sleep disorders only occur during REM sleep, and in others, sleep disorders may prevent sleepers from achieving REM sleep or enough REM sleep. Here's a quick rundown.<\/span><\/p>\n\n\n\n Nightmare disorder<\/span><\/a> is a <\/span>parasomnia<\/span><\/a> characterized by frightening and vivid dreams that may cause significant distress and impaired functioning to the sleeper. Nightmares stemming from nightmare disorder typically occur during REM sleep, and it's relatively rare, affecting only about 2 to 8 percent of the population. (<\/span>15<\/span><\/a>)<\/span><\/p>\n\n\n\n Obstructive sleep apnea (OSA) is a sleep disorder in which the throat muscles relax into the back of the throat and block the sleeper's airway, causing them to stop and start breathing repeatedly. As such, frequent awakenings are a common symptom of <\/span>sleep apnea<\/span><\/a>. Ultimately, Gartenberg says those repeated awakenings make it much more difficult to reach REM sleep. (<\/span>What Is REM Sleep? <\/span><\/h2>\n\n\n\n
What Happens During REM Sleep?<\/span><\/h2>\n\n\n\n
Stages of Sleep: Non-REM vs. REM Sleep<\/span><\/h2>\n\n\n\n
N1 (Stage 1) <\/span><\/h3>\n\n\n\n
N2 (Stage 2) <\/span><\/h3>\n\n\n\n
N3 (Stage 3) <\/span><\/h3>\n\n\n\n
REM (Stage 4) <\/span><\/h3>\n\n\n\n
Why Is REM Sleep So Important? <\/span><\/h2>\n\n\n\n
How Much REM Sleep Do We Need? <\/span><\/h2>\n\n\n\n
Tips for Getting Enough REM Sleep<\/span><\/h2>\n\n\n\n
Nix the Caffeine, Sugar, and Alcohol<\/span><\/h3>\n\n\n\n
Curb Blue Light Exposure<\/span><\/h3>\n\n\n\n
Optimize Your Sleep Environment <\/span><\/h3>\n\n\n\n
Sleep Disorders Associated with REM Sleep<\/span><\/h2>\n\n\n\n
Nightmare Disorder<\/span><\/h3>\n\n\n\n
Obstructive Sleep Apnea <\/span><\/h3>\n\n\n\n