Recovery and wearables briefing
REM sleep: why it matters and how to get more
REM is the dreaming stage of sleep, the part your wearable labels “REM”. Where deep sleep repairs the body, REM looks after the mind: mood, memory and learning. This briefing explains what REM does, puts a realistic number on how much you need, and shows the habits that protect it.
What REM sleep actually does
REM stands for rapid eye movement. During REM the brain becomes almost as active as when you are awake, the eyes flick behind closed lids, and most vivid dreaming happens. At the same time the body’s large muscles are switched off, which stops you acting out your dreams.
Emotional processing
REM is sometimes called “overnight therapy”. The brain replays emotional experiences while stress chemistry is at its lowest point of the day, which helps take the sting out of difficult memories. Poor REM is closely linked with low mood, anxiety and emotional reactivity.
Memory and learning
REM helps lock in skills and “how to” memories, and links new information with what you already know. This is part of why people often wake with a fresh angle on a problem.
Brain development
Newborns spend about half their sleep in REM, a sign of how important this stage is for building and wiring the brain. The share falls to adult levels during childhood.
Long-term health
In a large study of older men followed for 12 years, every 5% drop in REM was linked with a 13% higher death rate from any cause, with a similar pattern in a second group of adults. This shows an association, not proof that low REM causes harm, but it suggests REM is more than “just dreaming”.
How much you should be getting
Here are the percentage and the hours side by side, then translated into real numbers depending on how long you sleep.
The commonly cited REM range for healthy adults. Unlike deep sleep, REM stays fairly steady through adult life, with only a slow decline in later years.
The typical absolute amount for an adult getting the recommended 7 to 9 hours of sleep.
What that looks like at your sleep length
| Total sleep | REM at 20% | REM at 25% | Reasonable nightly amount |
|---|---|---|---|
| 6 hours | ~70 min | ~90 min | Just over 1 hour, often less |
| 7 hours | ~85 min | ~105 min | Around 1.5 hours |
| 8 hours | ~95 min | ~120 min | 1.5 to 2 hours |
| 9 hours | ~110 min | ~135 min | Around 2 hours |
When REM happens in the night
Sleep runs in cycles of roughly 90 minutes, and a full night has four to six of them. Each cycle moves through light sleep, deep sleep and then REM. The balance shifts as the night goes on: early cycles are rich in deep sleep, later cycles are rich in REM.
| Part of the night | Length of each REM episode | What it means |
|---|---|---|
| First cycle (about 90 minutes in) | ~10 minutes | A short first taste of REM. Deep sleep dominates this part of the night. |
| Middle of the night | ~15–30 minutes | REM episodes grow longer as deep sleep pressure eases. |
| Last 2 to 3 hours before waking | up to ~60 minutes | The richest REM of the night. An early alarm or a late bedtime with a fixed wake time cuts straight into it. |
How to read your wearable’s REM number
Wearables estimate your sleep stages from heart rate, heart rate variability and movement, not from brain waves, so the REM figure is an estimate, not a measurement. That said, REM is one of the stages they pick up reasonably well.
In a 2024 study comparing three devices against a clinical sleep study, the Apple Watch correctly detected REM about 83% of the time, the Oura Ring about 76%, and Fitbit about 67%. That is a fair match for tracking trends, not a diagnosis. If you also track heart rate variability, look at the two together: a stressful week often shows up as lower HRV and less REM.
Watch the weekly trend. Your own running average over weeks tells you far more than any single night.
Don’t compare devices. An REM figure from one brand is not the same as another’s. Compare yourself only to your own baseline on the same device.
Don’t chase a perfect score. Worrying about your sleep numbers can itself make sleep worse. One low night usually reflects a late night, a drink, or stress, not a problem.
How to get more REM sleep
You cannot switch REM on directly, but you can stop cutting into it. These levers are ordered roughly by how big a difference they make.
Protect the back end of the night
The single biggest lever. Aim for 7 to 9 hours and avoid cutting sleep short from the morning end, where most REM lives. If you need an earlier start, move your bedtime earlier rather than just setting an earlier alarm.
Go easy on alcohol
Alcohol is one of the strongest REM suppressors, especially in the first half of the night, and the more you drink the bigger the effect. If you do drink, earlier and less is better, and alcohol-free evenings are a simple experiment to watch on your tracker.
Keep a steady wake time and get morning light
REM is tied to your body clock and peaks in the early morning hours. A consistent wake time, with outdoor light soon after, keeps that timing stable so REM lands where it should.
Be aware of cannabis and some medications
Cannabis suppresses REM, and stopping it often brings a burst of vivid dreams. Many antidepressants and some other medications also reduce REM. Never stop a prescribed medication on your own; if you are concerned, raise it with your prescriber.
Address snoring and sleep apnoea
Breathing problems are often worst during REM, because the muscles that hold the airway open relax most in this stage. Each pause can pull you out of REM. Loud snoring, gasping, or habitual mouth breathing at night are worth assessing.
Wind down stress before bed
A racing mind and high evening stress break sleep into pieces, and REM, being the lightest-feeling stage, is easily interrupted. A calm last hour, low light and a slower breath all help. If stress and fatigue are running the show, this is something we can help with.
Sources
This briefing draws on sleep research, long-term health studies and recent wearable-validation work, translated into practical guidance for people tracking REM at home.
- Leary EB and colleagues. Association of rapid eye movement sleep with mortality in middle-aged and older adults. JAMA Neurology. 2020. Source for the 13% higher mortality per 5% reduction in REM.
- Walker MP, van der Helm E. Overnight therapy? The role of sleep in emotional brain processing. Psychological Bulletin. 2009.
- Ohayon MM, Carskadon MA, Guilleminault C, Vitiello MV. Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals. Sleep. 2004.
- Robbins R and colleagues. Accuracy of three commercial wearable devices for sleep tracking in healthy adults. Sensors. 2024. Source for REM detection accuracy of Apple Watch, Oura and Fitbit versus a clinical sleep study.
- Ebrahim IO and colleagues. Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research. 2013.
- Wichniak A and colleagues. Effects of antidepressants on sleep. Current Psychiatry Reports. 2017.
- Sleep Foundation. REM sleep: what it is and why it matters.
Use note: consumer wearables vary by sensor and algorithm. Compare yourself to your own baseline first, and use the figures here as a reality check rather than a target to hit.
Frequently asked questions
How much REM sleep do you need each night?
For healthy adults, REM sleep typically makes up about 20 to 25% of total sleep, which works out to roughly 1.5 to 2 hours for someone sleeping 7 to 9 hours. It comes in four to six episodes that grow longer through the night, so most REM happens in the last few hours before waking. There is a normal range rather than one right number, and your own trend over weeks matters more than any single night.
What does REM sleep do?
REM sleep is the stage where most vivid dreaming happens and the brain is almost as active as when awake. It helps process emotions, consolidate skills and link new learning with existing memories, and it is especially important for brain development in infants. Large studies have also linked lower REM with poorer long-term health, although that shows an association rather than proof of cause.
How can I get more REM sleep?
The biggest lever is getting enough total sleep and not cutting the night short from the morning end, where most REM occurs. Other helpful steps include limiting alcohol, keeping a steady wake time with morning light, being aware that cannabis and some medications reduce REM, and having snoring or possible sleep apnoea assessed. Prescribed medications should never be stopped without talking to the prescriber first.
Why do I have vivid dreams after a bad week of sleep?
This is usually REM rebound. When REM has been cut short by short nights, alcohol or some medications, the brain tends to enter REM sooner and stay longer once it gets the chance, which often brings more intense or vivid dreams. It is generally a normal catch-up response rather than a sign of a problem.
Reviewed by Rohan Smith, BHSc Nutritional Medicine · Elemental Health & Nutrition, Adelaide. Last reviewed 30 September 2026.
Important: This summary is general information, not personalised medical advice, diagnosis, or a treatment protocol. Speak with a qualified practitioner about your individual situation. Book a consultation →