REM Sleep: How Much You Need and How to Get More (UK)

Last updated: October 2026

REM (rapid eye movement) sleep is the stage when most vivid dreaming happens, and it is linked to memory and processing emotions. It makes up roughly a fifth to a quarter of adult sleep, mostly in the second half of the night. Getting enough total sleep and cutting back on alcohol protect it best.

Below: what happens in REM, how much you need by age, REM vs deep sleep, how to get more, and REM sleep behaviour disorder.

What is REM sleep?

Sleep has two types: non-REM (stages N1, N2 and the deepest, N3) and REM. You cycle through them roughly every 90 minutes, 4 to 6 times a night; our deep sleep guide has a full table of the stages. REM is named after the way your eyes dart about behind closed eyelids, and three things set it apart:

Your brain is busy. Brain activity looks very similar to when you’re awake, and this is when most dreams happen.
Your body is switched off. The muscles in your arms and legs are temporarily unable to move, which stops you acting out your dreams.
It comes later in the night. The first REM period is usually the shortest, around 10 minutes, and each one after is longer, so most REM sleep happens in the last few hours before you wake.

Waking while that muscle “off switch” is still on causes sleep paralysis. Realising you’re dreaming while staying in REM is lucid dreaming.

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Why REM sleep matters

Scientists are still working out exactly what REM does, but two jobs keep coming up.

Memory. Reviews list memory consolidation, turning the day’s experiences into lasting memories, as a likely role.
Emotions. Berkeley researchers have proposed that REM helps take the sting out of emotional experiences overnight. In one of their studies, people whose nap included REM became less reactive to angry and fearful faces; those who didn’t reach REM did not.

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How much REM sleep do you need?

There’s no official REM target. The NHS says adults need 7 to 9 hours of sleep on average, and at about 20 to 25% that is roughly 85 minutes to just over 2 hours of REM. Age matters too: a meta-analysis of 65 studies in 3,577 healthy people aged 5 to 102 found the share of REM falls gradually through adulthood, along with deep sleep and total sleep.

Age	REM as a share of sleep	What it means
Newborn babies	About half	Spread across day and night; it falls as they grow
Children and teenagers	Changes as they grow	Studied far less than adults
Around age 20	Just over 20%	About 1.5 to 2 hours in a 7 to 9 hour night
Middle age	Slowly falling	Normal ageing, not a sign of a problem
Over 80	About 17%	Roughly 70 to 90 minutes a night

The best test is how you feel: if you wake reasonably refreshed and don’t struggle to stay awake in the day, you’re very likely getting enough.

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REM sleep vs deep sleep: which is better?

Neither. They do different jobs and you need both.

	Deep sleep (N3)	REM sleep
Brain activity	Slow, strong waves	Fast, close to waking
Muscles	Relaxed, but can still move	Arms and legs temporarily unable to move
Dreams	Less common	Most vivid dreaming
When in the night	Mostly the first half	Mostly the second half
Share of adult sleep	Roughly 10 to 25%, falling with age	About 20 to 25%, falling gently with age
Linked with	Physical repair, immune support, memory	Dreaming, memory, emotional processing

It’s normal to have more REM than deep sleep, and light sleep (Apple Watch calls it “core”) is usually the biggest share of all.

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What reduces REM sleep

Cutting your night short

Because REM periods get longer towards morning, an early alarm takes a bigger bite out of REM than out of deep sleep. Regular short nights add up; see sleep debt.

Alcohol

A review of studies in healthy volunteers found alcohol delays the first REM period at every dose and cuts total REM at moderate and higher doses. A 2025 meta-analysis of 27 studies found REM was disrupted after as little as about two drinks. See alcohol and sleep.

Some medicines

Most antidepressants reduce REM and delay its start, especially those that act on serotonin, such as SSRIs. A review found the effect is biggest early in treatment and lessens over time. It’s a known effect: never stop or change a prescribed medicine because of it, and talk to your GP or pharmacist if you’re worried.

A hot bedroom

A review found that in real life, with bedding and nightwear, a hot room increases waking and reduces both REM and deep sleep.

REM rebound

After a short night, you tend to get extra REM the next night, called REM rebound. Vivid dreams in the first week or two after cutting out evening drinks are often put down to the same thing. If bad dreams keep waking you, see nightmares.

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How to get more REM sleep: 6 things that help

You can’t switch REM on directly, but you can give it time and remove what cuts it short.

Sleep long enough. Most REM comes at the end of the night, so enough total sleep is the biggest lever.
Keep a fixed wake time. The NHS suggests getting up at the same time every day, which helps protect the REM-rich morning hours.
Drink less, and not late. NHS Every Mind Matters suggests avoiding alcohol and nicotine for 1 to 2 hours before bed.
Watch the afternoon coffee. A late cup can delay sleep and shorten your night. See how long caffeine lasts.
Wind down for an hour. The NHS lists stress and anxiety among the most common causes of poor sleep and suggests relaxing for at least an hour before bed. Try our bedtime routine for adults.
Keep your bedroom cool, dark and quiet.

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REM sleep on your tracker: how accurate is it?

REM is defined by brain waves, eye movements and muscle tone in a sleep lab. A watch or ring estimates it from movement and heart rate instead. When seven consumer trackers were tested against lab recordings in 34 young adults, most told sleep from wake well, but sleep stage results were inconsistent, and worse on disrupted nights. Treat one night’s REM figure as a rough guess and watch trends over weeks; see do sleep trackers work?

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Supplements and REM sleep: what to know

To be straight with you: no supplement is proven to increase REM sleep, so be wary of any that promises it. A supplement can still be part of a calm evening routine. Magnesium contributes to the normal functioning of the nervous system, normal psychological function and the reduction of tiredness and fatigue. Our Magnesium Glycinate Sleep Complex is a berry drink combining magnesium bisglycinate and citrate with glycine, L-theanine, chamomile, passionflower, hops and oat straw, and many people make it part of their wind-down. See magnesium for sleep and melatonin in the UK.

Our products are for adults only. We don’t recommend our products during pregnancy or breastfeeding.

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REM sleep behaviour disorder (RBD)

In RBD the muscle “off switch” doesn’t work properly, so people physically act out dreams, which are often vivid, action-filled and unpleasant.

Signs of RBD

Shouting, talking or screaming during dreams
Punching, kicking, flailing arms or jumping out of bed
Being able to remember the dream if woken during an episode

It usually comes on gradually and is more common in men and in people over 50. Unlike night terrors, which happen early in the night and are rarely remembered, RBD comes from REM sleep. Sleep talking on its own is common.

Why it’s worth getting checked

RBD can be linked with some antidepressants, with narcolepsy, and with conditions such as Parkinson’s disease and dementia with Lewy bodies. When RBD has no other obvious cause, it can be an early sign of one of these conditions, sometimes many years ahead. In a large international study of 1,280 people with confirmed RBD, about 6% a year went on to develop one.

That sounds frightening, but it’s why getting checked helps: it means the right follow-up. A specialist confirms RBD with an overnight video sleep study, and treatment may include melatonin or clonazepam on prescription. If you are acting out dreams, see your GP rather than guessing.

Keeping safe at night

Move sharp or breakable objects away from the bed
Use padding or cushions around the bed, and consider bed rails
Consider sleeping in separate beds until it’s under control

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When to see a GP

You act out dreams by shouting, punching or kicking. Mention any new medicines.
You snore loudly, gasp or choke in your sleep, or your breathing stops and starts. (signs of sleep apnoea).
You feel very tired during the day even after a full night.
Poor sleep has lasted months or makes it hard to cope; see insomnia.

Want to wake after a full cycle rather than mid-REM? Use our sleep calculator to count back from your alarm in 90-minute cycles.

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FAQs

How much REM sleep is normal?

For most adults, about 20 to 25% of total sleep, or roughly 85 minutes to just over 2 hours in a 7 to 9 hour night. The share falls gently with age, to about 17% in people over 80.

Is 2 hours of REM sleep good?

Yes. Around 2 hours is normal for an adult who sleeps a full night. A tracker’s figure is only an estimate, so look at how you feel and at trends over weeks rather than one night.

Is it better to have more REM or deep sleep?

Neither is better. Deep sleep comes mostly early in the night and REM mostly late, and you need both. It’s normal for adults to have more REM than deep sleep, especially from middle age.

What happens if you don’t get enough REM sleep?

Usually your body catches up: after a short night you tend to get extra REM the next night, called REM rebound. Regularly short nights leave you tired, and research links REM with memory and processing emotions.

Does alcohol affect REM sleep?

Yes. Alcohol delays the first REM period at every dose studied and reduces total REM at moderate and higher doses. A 2025 meta-analysis found effects after as little as about two drinks.

Do babies get more REM sleep?

Yes. Newborns spend about half their sleep in REM, and the share falls as they grow. By around age 20 it is just over a fifth of sleep.

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