What Is REM Sleep? (And Why It’s Important)

Seriously, What Is REM Sleep?

REM sleep is something I’ve heard about a ton, but all I know is that it’s the part of your sleep where your eyes do some funky stuff (hence the name – Rapid Eye Movement). So what actually is it, and why is REM sleep so important? 

Sleep is one of the more mysterious topics in science, and for how common it is (everyone does it), relatively understudied. It wasn’t long ago that sleep was viewed as an activity in which the body and brain laid dormant, but that couldn’t be further from the truth.

REM sleep is a cycle where your:

This dream state is actually quite similar to an awake state, and consumes between 20-25% of our time asleep. There’s a theory that we are temporarily paralyzed during REM to protect us from acting out our dreams. This is called REM Atonia, something that can become faulty in a very few number of unlucky people who end up acting out their dreams.

trying to fall asleep

Why Is REM Important?

Learning and Memory

When it comes to memory storage, REM plays a significant role in the management and consolidation of long term memory.

We can recall new information for around 40 hours without sleep. Beyond that, REM sleep is required in order to convert memories from short term to long term. For example, in a study that tested the effects of REM sleep on rats, scientists found that brain patterns during the rat’s sleep were identical to the patterns displayed while running though a maze earlier in the day. These brain patterns were so similar that scientists could even tell which part of the maze the rat was dreaming about. What’s most interesting is that when doing the same maze the next day, rats who slept through a REM induced cycle far outperformed rats who didn’t get any REM sleep. 

men in black memory erase

Emotional Intelligence

“Sleep essentially is resetting the magnetic north of your emotional compass”

-Matthew Walker, director of the Sleep and Neuroimaging Lab at the University of California, Berkeley.

A study done by Matthew Walker found that those who reached REM sleep during a nap were better able to recognize positive emotions (happiness) in pictures of people, compared with participants who didn’t achieve REM who were more sensitive to negative emotions (anger.)

Biologically, this makes sense. If you’re more fatigued, you benefit by having a heightened awareness to threats for the sake of short term survival (hunting prey for food), whereas if you’re well rested, you stand to benefit more from noticing positives for long term survival (like relationship building). 

Fear Response / Anxiety

As touched on above, a lack of REM sleep can contribute to heightened anxiety. A theory by Walker is that dreaming, which occurs during REM, combs through the past days events, stripping away the negative emotions attached to memories. Basically, this removes the emotions attached to the memory, not the memory itself. When REM isn’t achieved, there’s more emotion attached to your memories, resulting in increased levels of anxiety

hyperventilating from anxiety

Another study tracked the emotional responses to “emotionally stirring” video clips of 18 young adults, both after a full night of sleep and after a night without sleep. After the sleepless night, brain scans showed that the area of the brain responsible for regulating anxiety levels was shutdown, while other areas responsible for deeper emotions was over active. 

“Without sleep, it’s almost as if the brain is too heavy on the emotional accelerator pedal, without enough brake”

-Matthew Walker.

But after a full night of sleep, brain activity was restored and anxiety levels dropped significantly. Note that in this case, it was in deep sleep, which is a cycle of Non-REM, that regulated emotions.

Tips For Improving Your REM Sleep (And Sleep In General)

Knowing how important a good nights sleep is, there are some tips for improving your overall sleep.

Reduce Intake of alcohol

Though alcohol reduces the time it takes to fall asleep, it significantly disrupts the 2nd half of your sleep. But it also increases deep sleep which is responsible for rest and restoration. 

Most of the negative effects come from disruptions to REM. Alcohol, at a high dose, reduces the amount of total REM sleep.

chugging a beer

Reduce Intake of Caffeine 

Caffeine, being a psychoactive stimulant, has a half life of about 5 hours – meaning half of the original substance is is still in your body 5 hours later. The effects of caffeine vary from person to person, but it should be avoided within at least 6 hours of bedtime


While there isn’t a ton of research on the effects that weed has on sleep due to it recently being an illicit drug, there is some belief that it can negatively impact REM. 


New research suggests exercise take place no later than 1 hour before bed, to maximize your sleep quality. 

Stay Off The Screens

Maybe one of the most destructive pre-sleep practices, looking at artificial light before bed causes a whole list worth of issues:

  • Decrease in melatonin production which is essential for sleep.
  • Exposure to certain things can cause stress, firing up your adrenal glands which release cortisol.
  • Visual stimulation causes an increase in electrical activity in the brain, causing you to perk up rather than calm down.

phone addiction