Take a 7-hour night with 40 minutes of REM on the watch: 9.5 percent of your sleep. Now look at the clock. Most REM arrives in the last part of the night, close to your usual wake-up time. So the end of the night decides it. That is the short answer to how to improve REM sleep: sleep long enough, and do not cut the end. A week of short nights cost mainly REM sleep. Alcohol and some medicines come next.
Key takeaways
1. How to improve REM sleep starts with timing: REM is about 20 to 25 percent of sleep in healthy adults and comes mostly in the last hours before waking.
2. No guideline sets a REM target. 40 minutes in a 7-hour night is under 10 percent, below the usual range.
3. Lever one is enough sleep without cutting the end: a week of short nights cost mainly REM.
4. Alcohol, even up to about two drinks, and common antidepressants lower REM. Never change a medicine on your own.
5. Watches got the group average close but single nights poorly. Read a week, not a night.
What REM sleep is, and why it comes before you wake
REM sleep is the stage named for its rapid eye movements. Your muscles go nearly paralyzed while dreams play out. A sleep lab spots it from brain waves, muscle tone and eye movements. It builds through the night and peaks toward your usual wake-up time. Deep sleep, whose slow brain waves are strongest in the first cycle, comes first. Neither is better; they sit at opposite ends of the night.
Why the morning? In a lab with no clue to the time, REM grew the longer sleep went on and peaked when sleep ended at the usual wake time. One catch: that was 8 men. More in how much deep sleep is normal and all four sleep stages at a glance.
How much REM sleep is normal, by age
In healthy adults, about 20 to 25 percent of sleep is REM. That is roughly 84 to 105 minutes in a 7-hour night and 96 to 120 in an 8-hour one. No guideline sets a REM target: recommendations cover total sleep, 7 to 9 hours for adults. With age, the share drops a little in some data and not significantly in others.
REM share means REM minutes divided by total sleep, as a percent. As an example, take a 7-hour night. Is 30 minutes of REM enough? It is 7.1 percent, well below the usual range. Is 40 minutes good? It is 9.5 percent. That sits under the 15 percent mark from a mortality study, though one lab saw values that low in healthy sleepers over 60. An hour is 14.3 percent, 2 hours 28.6. And 90 minutes, at 21.4 percent, is typical.
| REM a night | Share of a 7-hour night |
|---|---|
| 30 min | 7.1% |
| 40 min | 9.5% |
| 60 min | 14.3% |
| 90 min | 21.4% |
| 120 min | 28.6% |
One lab scored 100 healthy sleepers under today's rules. The median REM share was 15.5 percent at 30 or younger (range 7.5 to 23.6). Over 60 it was 10.3 percent (range 1.9 to 21.9). As a rough estimate, that is about 64 and 39 minutes a night. At home, in 1,997 adults with an average age of 59, those without REM sleep behavior disorder averaged 21.9 percent REM.
| Group | Median or mean, % of sleep | Range, % of sleep |
|---|---|---|
| Sleep lab, age 30 or younger | median 15.5 | 7.5 to 23.6 |
| Sleep lab, over 60 | median 10.3 | 1.9 to 21.9 |
| At home, general population, average age 59 | mean 21.9 | |
| Textbook range, healthy adults | 20 to 25 |
Across 344 samples of healthy adults, the share fell only about 0.6 points per decade, roughly 12 minutes of a 7-hour night from 19 to 75. Where people were carefully checked for mental health problems first, no drop appeared between 40 and the mid-70s.
A 2019 meta-analysis of 169 studies found no significant change per decade, and how big the drop looks depends on how carefully people were screened. A study of men alone saw more: in 149 healthy men, REM fell about 10 minutes per decade from midlife to ages 71 to 83.
Does a low REM number matter?
It may, but the evidence is association, and more REM is not automatically better. In 2,675 men averaging 76, a REM share 5 points lower went with 13 percent higher death risk, followed for roughly 12 years. One recorded night, and no proof of cause.
A younger cohort of men and women showed a similar pattern, and REM under 15 percent went with higher mortality. In a third cohort, the bottom quarter for REM carried about 1.5 times the death risk of the top quarter over 11 years.
What about dementia? In 321 people over 60, each percentage point less REM went with about a 9 percent higher dementia risk. Only 32 of them developed it. When five cohorts with 4,657 adults aged 60 and over were pooled, the association was not significant, though most cohorts leaned that way.
In depression, REM often starts earlier and takes up more of the night. Chase habits that moved REM in studies, not a figure.
Protect the last hours of the night
Keep your alarm where it is and go to bed earlier. Give yourself at least 7 hours. That is lever one, because REM peaks near your usual wake-up time. When 35 healthy adults spent a week at 6 hours in bed instead of 10, the short week cost mainly REM. Cut the end of the night, and you cut REM. To plan it, work back from your wake-up time.
A harsher trial, five nights of 4 instead of 9 hours in 27 healthy adults, lowered REM in minutes and share. Extreme, but the direction holds.
Have your last coffee early. In a meta-analysis of 24 studies, caffeine cut total sleep by 45 minutes on average. Its estimate: a cup at least 8.8 hours before bedtime. Its abstract reports no REM result, but shorter sleep loses its REM-rich end.
The evening: alcohol, cannabis, heat and late workouts
Alcohol is the evening factor with clear data. Even a low dose, up to about two standard drinks, pushed the first REM period later and shortened REM, and each extra drink made it worse. So the less you drink, the more REM you keep. On nights that matter, skip it.
That makes the nightcap a half-truth. In lab studies of healthy volunteers, alcohol made falling asleep easier and the first half of the night calmer. Then the second half broke up, and at every dose REM started later. REM latency is that wait: the time from falling asleep to the first REM period.
| What | Effect on REM | Who was studied |
|---|---|---|
| 6 instead of 10 hours in bed for a week | Mainly REM lost | 35 healthy adults, crossover |
| 4 instead of 9 hours for 5 nights | Less REM, in minutes and share | 27 healthy adults, crossover |
| Alcohol, even up to about 2 standard drinks | First REM later, less REM, worse with dose | 27 studies, healthy adults |
| A hot bedroom, with bedding | Less REM and deep sleep, more time awake | Lab studies (review) |
| SSRIs, SNRIs, tricyclic antidepressants | Less REM, first REM later | Sleep-lab studies (review) |
| Mirtazapine, trazodone, agomelatine | No or minimal change | Sleep-lab studies (review) |
| Benzodiazepine sleeping pills | Less REM and deep sleep | Clinical trials (systematic review) |
| Cannabis | No consistent change; REM rebound after stopping regular use | 18 sleep-lab studies (review) |
| One evening workout | First REM 7.7 minutes later on average; no measurable harm to sleep overall | 23 studies, healthy adults |
Cannabis is murkier: a 2025 review of 18 sleep-lab studies found no consistent change in sleep stages. Earlier reports of less REM rested on small trials using high doses of THC. Quitting is clearer: stopping regular use brought worse sleep and a REM rebound, extra REM after it was held down.
Keep the bedroom from getting hot. With bedding and clothes as at home, heat cut deep and REM sleep and added time awake. Cold, with enough bedding, did not change the stages.
Your evening workout can stay. In a meta-analysis of 23 studies, one evening session delayed the first REM period by 7.7 minutes on average, with no measurable harm to sleep overall. Only hard exercise ending within an hour of bedtime might. More on what alcohol and heat do to deep sleep.
Medicines and sleep apnea: when the cause sits elsewhere
Common SSRIs, SNRIs and tricyclic antidepressants lower REM and delay its start, while mirtazapine, trazodone and agomelatine barely change it. Benzodiazepine sleeping pills reduce both deep sleep and REM. Never stop a medicine on your own. Untreated sleep apnea can hold REM down too: in sleep-lab records of 335 patients, REM and deep sleep could rebound on the very first night CPAP supported their breathing.
Acting out dreams is a different signal. In REM sleep behavior disorder, the usual muscle paralysis of REM fails. It is rare. Among 1,997 adults, 368 said they acted out dreams, but only 21 met the sleep-lab criteria, about 1 percent. Once confirmed, it is serious: of 1,280 people with a lab diagnosis, about 6 percent a year were diagnosed with Parkinson's or a related brain disease. By 12 years, it was 73.5 percent. The antidepressants above may also trigger or worsen it.
What causes a lack of REM sleep? The causes with study data behind them: nights cut short at the end, alcohol, certain medicines, untreated sleep apnea, a hot bedroom, and to a small degree age, or simply a tracker that misplaces REM.
Reading your tracker's REM number
Trust the average, not the night. In a study of 35 healthy adults aged 20 to 50, three popular wearables came within 3 to 7 minutes of the sleep lab's group average for REM. Night by night, they agreed poorly. One catch: these were healthy, mostly younger sleepers on 2023 devices. In another study of 34 healthy young adults, five of six trackers placed the first REM significantly later than the lab did.
| Device | Device, minutes | Sleep lab, minutes | People analyzed |
|---|---|---|---|
| Oura Ring Gen3 | 93 | 96 | 35 |
| Fitbit Sense 2 | 90 | 97 | 33 |
| Apple Watch Series 8 | 102 | 96 | 29 |
How to read yours:
- Look at a week's average, not one night.
- Compare weeks on the same device, never devices or people.
- Judge change by your habits: sleep length, alcohol.
Your huuman Coach reads your Apple Health next to your training, sleep stages and REM included. See also what your watch's night heart rate means.
This week:
- Same wake time every day. Move bedtime earlier, not the alarm.
- At least 7 hours of sleep.
- As little alcohol as you can; none on nights that matter.
- Last coffee early in the day.
- A bedroom that does not get hot.
- On an antidepressant or sleeping pill? Raise REM with your doctor; do not change the dose.
More health topics to explore
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About this article · Written by the huuman Team. Our content is based on peer-reviewed research and clinical guidelines. We follow editorial standards grounded in scientific evidence.
This article is for educational purposes only and does not constitute medical advice. Health and training decisions should be discussed with qualified professionals.
