What is REM Sleep and Why Do We Need It?

5 min read

Last Modified 12 October 2021 First Added 6 August 2021

By Nat Took

REM sleep definition:

a kind of sleep that occurs at intervals during the night and is characterised by rapid eye movements, more dreaming and bodily movement, and faster pulse and breathing.

Source: Google Dictionary

Sleeping isn’t just about laying down and relaxing in bed. Your body and brain have a lot on whilst you get your shut-eye. In fact, you go through various stages of sleep when you rest at night. It’s quite an intense process, and during these cycles, you’ll go through NREM (non-rapid eye movement) and REM (rapid eye movement) sleep. In this post we’ll take a look at REM sleep and why it’s so important for your health.

What is REM sleep?

REM sleep stands for rapid eye movement. During this type of sleep your eyes move rapidly, but no visual information is sent to the brain. During REM sleep you can have intense dreams, as your brain is more active. On the other hand, NREM is non-rapid eye movement, your eyes do not move. It’s during NREM that deep sleep occurs.
Many people confuse REM sleep with deep sleep but they’re different. Deep sleep occurs during the third phase of non-REM sleep, not during a REM sleep cycle.

What are the signs of REM sleep?

You may not be able to tell if you’re in REM sleep (as you’re asleep at the time!), but you can tell if someone else is in a REM sleep stage. Signs of REM include:

  • Eyes moving rapidly under the eyelids
  • Face and limbs may twitch
  • Sexual arousal can occur
  • Breathing becomes fast and irregular

Other signs that you’ll not be able to see, but can happen in the body during REM include:

  • A change in body temperature
  • Heart rate increases to near waking levels
  • The brain increases oxygen consumption
  • Blood pressure increases

How much REM sleep do you need?

In total, an adult needs around 90 minutes of REM sleep a night. This should work out as between 20-25% of your typical 7-8 hours of sleep a night. The required amount of REM is much higher in infants who need about 50% of REM sleep.

REM sleep normally happens after you’ve been asleep for about 90 minutes. You have several stages of this type of sleep each night, going in and out of REM and NREM sleep. Your first period of REM normally lasts for 10 minutes, and each REM stage that follows gets longer. The last stage of REM can be as long as an hour.

Why is REM sleep important?

REM sleep is a key part of the sleep process and has various crucial functions that are different to those of NREM and deep sleep. Though getting the correct amount of all types of sleep is likely to be necessary, REM affects certain areas of your body. Here are some of the reasons why REM sleep is so important:

Learning and memory – There are studies that suggest that if people are unable to get enough REM sleep, they have difficulty with their memory. One study suggested those not getting enough REM sleep have difficulty remembering what they were taught before they fell asleep. Another study showed that not getting enough REM for just 4 days affected cell proliferation in the part of the brain that contributes to long-term memory.

Central Nervous System (CNS) development – It’s thought that REM sleep is important for brain development in babies. One study suggests that REM is responsible for the neural stimulation that is needed to develop mature neural connections.

What happens if you don’t get enough REM?

Not getting enough REM can have negative effects on your overall health. Various research has linked a lack of REM sleep to:

  • Migraines
  • Reduced coping mechanisms
  • Weight gain

How to improve REM sleep

If you’re worried about whether you’re getting enough quality REM sleep, there are ways you can help to improve this situation. Most of these methods are also general tips for sleeping better, which will have a knock-on effect for your REM sleep.

Firstly, having a good bedtime routine, which prepares your mind and body for sleep can help your overall sleep, and so help improve your REM. This will maximise the amount of sleep you get, which can increase the number of REM phases. It’s also important to reduce waking during the night.
Although you may not be able to control this all the time, if you ensure your sleep environment is right for you, this should help you to sleep through the night. So, make sure your room is at a comfortable temperature, use blackout blinds or an eye mask if there are bright lights outside, and even use earplugs if you’re in a noisy area.

Another way to improve your REM sleep is to avoid alcohol before bed. Alcohol may help you fall asleep quicker, but the quality of your sleep is impacted. Studies have shown that the total nightly REM is reduced by moderate to high alcohol intake.

Related: Does Alcohol Affect How We Sleep?

The best way to improve your REM sleep is to simply get enough quality sleep. It’s an important part of your nightly sleep cycles, which can affect your overall health. Sleep is important for your wellbeing, so don’t let it slip and try to make sure that you’re getting enough!

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