What is REM sleep and why is it important?

Amy Gallagher
Senior Sleep Physiologist at Cromwell Hospital
06 October 2023
Next review due October 2026

Rapid eye movement (REM) sleep is important for our health. It’s believed that not getting enough REM sleep may have an impact on our mental health, memory, and concentration.

Here, I look at what REM sleep is and offer some tips to help you make sure you get enough.

person lying in bed

What is REM sleep?

Getting enough sleep is essential for our wellbeing. But it’s not just the amount of sleep we get that matters – it’s the quality too. When we go to sleep, we need to spend enough time in non-REM and REM sleep to feel well rested in the morning.

As we progress through our sleep cycle, our non-REM sleep deepens. We then move into the fourth stage of sleep, known as rapid eye movement (REM) sleep.

During REM sleep, our body shuts down muscle control, and this is the phase where we have most of our dreams. After completing the REM phase, our sleep cycle begins again.

How much REM sleep do you need?

It’s thought that adults need between one-and-a-half to two-and-a-half hours of REM sleep each night. But, because REM sleep is believed to play a role in brain development, babies are thought to need much more REM sleep than adults.

Is REM sleep the same as deep sleep?

Rapid eye movement (REM) sleep is not the same as deep sleep. Studies have shown that during REM sleep our brain activity, blood pressure, and heart rate is similar to when we’re awake.

To feel refreshed when we wake up, we ideally need to go through five or six sleep cycles. Below are the four sleep stages.

Stage one non-rapid eye moment (NREM) sleep

This is the first stage of sleep.

Stage two non-rapid eye movement (NREM) sleep

This is a light sleep stage, but deeper than stage one and believed to be important for our memory.

Stage three non-rapid eye movement (NREM) sleep

Also known as ‘slow wave sleep’. This deep sleep phase is important for repairing the body, restoring energy, and maintaining health.

Stage four rapid eye movement (REM) sleep

This phase is important for memory and our brain function and development.

What are the symptoms of a lack of REM sleep?

REM sleep is an essential part of our sleep cycle, and not getting enough good quality sleep over time can impact our health. It can affect our blood pressure, and make you more likely to experience depression and anxiety.

Other symptoms of poor sleep can also include:

  • feeling irritable
  • increased forgetfulness
  • being unwell more often
  • feeling hungrier than usual
  • finding it difficult to concentrate

How can I make sure I get enough REM sleep?

Getting enough REM sleep is important for our memory, concentration, and mood. The best way to increase your time in REM sleep is to make sure you set yourself up to have quality sleep each night. Below are six steps to help you get a good night’s sleep.

  • Don’t watch the clock. Avoid checking the time regularly at night as you try to fall asleep. This can make you feel anxious about how much sleep you’re going to get, which can make falling asleep more difficult.
  • Banish blue light. Don’t use smartphones or laptops for at least two hours before bed as they produce blue light, which can prevent sleep.
  • Go to bed when you’re tired, but not too early. If you’re not falling asleep whilst in bed, it’s better to get up and go back to your bedroom when you feel sleepier.
  • Get into a routine. Try to get out into the daylight in the morning, and wake up and go to sleep at the same time each day. This can help regulate your circadian rhythms (your internal body clock), which can help you get better quality sleep.
  • Cut back on caffeine and alcohol, and stop smoking if you smoke. They are all stimulants that can affect your sleep.
  • Say no to naps. It can be difficult if you feel tired, but try not to take naps during the day as this can impact your sleep at night.

If you’re struggling to sleep at night, or are affected by daytime sleepiness, visit your GP who will be able to offer support and advice.

Are you interested in learning more about your health? Discover more about our range of health assessments.

Amy Gallagher
Amy Gallagher
Senior Sleep Physiologist at Cromwell Hospital



Lucy Kapoutsos, Health Content Editor at Bupa UK

    • Barbato G. REM Sleep: An Unknown Indicator of Sleep Quality. Int J Environ Res Public Health. 2021 Dec 9;18(24):12976. doi: 10.3390/ijerph182412976
    • What is REM sleep? The National Sleep Foundation. Published 1 November 2020
    • Sleep deprivation. The sleep charity. Last updated December 2021
    • Sleep calculator. The sleep charity. Last updated December 2020
    • Blumberg MS, Lesku JA, Libourel PA, Schmidt MH, Rattenborg NC. What Is REM Sleep? Curr Biol. 2020 Jan 6;30(1):R38-R49. doi: 10.1016/j.cub.2019.11.045
    • Sleep patterns. The sleep charity. Last updated December 2020
    • Scenario: managing short-term insomnia (less than 3 months duration). NICE Clinical Knowledge Summaries. Last revised May 2022
    • Circadian rhythms. National institute of general medical sciences (NIH). Accessed October 2023

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