What is REM Sleep?
REM sleep, which means “rapid eye movement sleep,” is one of the 4 stages of sleep (along with light, deep and wake) that your body’s sleep cycles consist of. It is known as the “mentally restorative” stage of sleep when the brain converts short-term memories into long-term ones. Your brain is very active during REM sleep and it is when the most vivid dreams occur.
What Happens in REM Sleep?
The following physiological changes occur during the REM stage of sleep:
- Eyes move rapidly back and forth behind closed eyelids
- Heart rate and blood pressure rise to levels nearly as high as when you’re awake
- Respiratory rate speeds up and becomes erratic
- Brain consumes more oxygen and its activity increases significantly
- Face and limbs may twitch
Below is a chart representing brain waves measured by an EEG when a person is awake, in REM sleep, and in non-REM sleep:
Your brain is almost as active in rapid eye movement sleep as when it’s awake, which is why most dreaming happens during this time. As a precautionary measure, your brain also sends signals to immobilize your arms and legs in order to prevent you from acting out your dreams.
Is REM Deep Sleep?
REM sleep and deep sleep (also referred to as slow wave sleep) are very different stages of sleep. Deep sleep is the “physically restorative” stage when muscles repair themselves and cells regenerate. It precedes REM sleep in a normal sleep cycle, and unlike REM your heart and respiratory rate decrease during deep sleep.
Why is REM Sleep Important?
REM sleep is the time when new learnings from the day are committed to memory. Beyond the obvious value this has for anyone, it’s significant to athletes from the perspective of technical skills worked on or practiced that day--they are retained during REM sleep, so failing to get the proper amount at night can prevent you from seeing the benefits of your practice that day.
More generally speaking, there’s been research to suggest that when people are deprived of REM sleep they have troubling recollecting things they are taught before falling asleep.
How Much REM Sleep Do You Need?
Your first period of REM sleep each night usually occurs within 90 minutes of falling asleep, and only lasts about 10 minutes. On average you’ll go through 3-5 REM cycles per night, with each episode getting longer as the night progresses. The final one may last roughly an hour.
For healthy adults, spending 20-25% of your time asleep in the REM stage is a good goal. If you get 7-8 hours of sleep, around 90 minutes of that should be REM.
The normal amount of REM sleep also declines with age, beginning with infancy (when it may be greater than 50% of total sleep time) and extending all the way through adulthood.
Learn More: How Much REM Sleep Should You Get a Night?
Consequences of Lack of REM Sleep
As mentioned above, not getting enough REM sleep can negatively impact your brain's ability to learn and create new memories.
Additionally, because the majority of your REM sleep tends to come towards the end of your night in bed (and after deep sleep, which your body prioritizes when it needs to catch up on sleep), a lack of REM is often a sign of sleep deprivation. Chronic sleep deprivation has been linked to greater risk of obesity, Type 2 Diabetes, dementia, depression, cardiovascular disease and cancer.
There has also been research to show that insufficient REM sleep may cause migraines.
How to Get More REM Sleep
Overall, whatever you can do to improve your sleep habits and behaviors will also help you get more REM sleep. This begins with simply making an effort to spend more time in bed. Here are 45 tips to help you sleep better.
There are also two other things in particular that stand out with how to increase REM sleep. The first is a concept we refer to as sleep consistency--going to bed and waking up at the same time each day (or as close to that as possible). Your body functions more efficiently when it is on a regular schedule, and this applies to sleep as well. We ran an analysis of sleep data from 25,000 WHOOP members, and the results showed a significant rise in the nightly amount of REM sleep as the percentage of sleep consistency over a 4-day span increased:
The second big thing is to stay away from alcohol before bed. When your body is forced to process alcohol during sleep, it has difficulty getting past light sleep and into the deeper stages.
How Do You Know How Much REM Sleep You’re Getting?
With the WHOOP Strap 3.0, you can monitor your sleep in detail and learn exactly how much time you spend in each stage of sleep. The WHOOP app also features a Sleep Coach that uses your own circadian rhythm to recommend daily bed and wake times to optimize the quality of your sleep.
WHOOP will let you know how much REM sleep you’re getting and help give you a better understanding of what you can do to get more of it.