Header burger open
Search Logo

Jump To

Currently Viewing:

NREM VS REM – 7 Key Differences

a profile image of TSA author Andjela

Written by Anđela Rajković

Sleep Consultant

Featured image of nrem vs rem.

8 November 2023 7 min read

NREM vs REM sleep – what are the differences and is one more significant than the other? Let's find out!

Sleep is a mysterious thing. We all do it, we know it's important, but sleep scientists are still trying to figure out all of its nuances – and so, we do too.

For instance, two important terms in sleep science are NREM sleep and REM sleep, which people sometimes confuse with one another – mostly because they only know about the latter. So, do you feel like it's time for NREM vs REM? Let's give it a shot!

1. NREM is a non-eye rapid movement stage whereas REM is a rapid eye movement sleep stage.

NREM is a non-eye rapid movement stage of sleep, during which your body and brain are resting. This stage can be divided into four different stages: N1, N2, N3, and N4.
REM is a rapid eye movement sleep stage, during which you experience more dreaming and your eyes move quickly from side to side. This stage accounts for around 20-25% of your total sleep time.
So what's the difference between the two?

An image of a woman sleeping on a couch with a limited space.

Well, as mentioned before, NREM is a stage of deep rest for your body and brain, while REM is when you experience the majority of your dreaming. Additionally, REM is thought to be important for memory consolidation and learning. Some scientists also believe that REM may be important for regulating your mood.

2. Both NREM and REM stages alternate periodically throughout the night.

To fully understand these alternations, we first have to understand the sleep stages and sleep cycles.
There are two categories – NREM and REM. Between those two – there are four stages of sleep – three NREM and one REM. Non-REM sleep can be subdivided into three stages- N1, N2, and N3. These stages are defined by the different brain waves patterns exhibited during each stage.
Stage 1, or N1 sleep, or light sleep is the lightest stage of sleep and is characterized by fleeting moments of drowsiness following falling asleep. This stage of a sleep cycle normally lasts just one to five minutes.

Stage 2, or N2 sleep, is considered a transitional stage between light and deep sleep. It is during this stage that the body starts to relax and prepares for deep sleep. This stage normally lasts 10-25 minutes.

Stage 3, or N3 sleep, is the deepest and most restorative stage of sleep. This stage is also known as slow-wave sleep or delta sleep due to the slow brain waves that are exhibited during this stage. This stage normally lasts 20-40 minutes.

An image of a young man sleeping in hot weather in his bed.

REM sleep is characterized by rapid eye movements and increased brain activity. This stage is considered to be the dream state of sleep. Dreams during this stage can be very vivid and realistic. REM sleep normally lasts for 90 minutes.

Both NREM and REM stages alternate periodically throughout the night.

NREM and REM cycles alternate throughout the night in a pattern that looks something like this: N1-N2-N3-N2-REM. That pattern is then repeated several times throughout the night with each cycle getting progressively shorter. The first half of the night is mostly made up of NREM sleep with REM sleep becoming more prevalent in the second half of the night.

According to the National Sleep Foundation, both types of sleep are essential for different functions. NREM sleep is essential for bodily recovery and growth. It may also bolster the immune system and other key bodily processes. REM sleep is critical for cognitive functions like memory, learning, and creativity.

3. Each sleep starts with NREM whereas the REM stage occurs in the end.

There are several reasons why sleep always starts with NREM and ends with the REM stage, but the one we're most certain of is that the body needs time to relax and regenerate after a long day.
The NREM stages allow the body to do this. During NREM (especially N1 and N2) is when our muscles are most relaxed, our body temperature is at its lowest, brain function is slowest, and so on.

An image of a woman sleeping and breathing in bed.

As we've said previously, people progress through the different sleep stages in the following order: N1-N2-N3-N2-REM. This sequence allows the body time to properly relax and regenerate after a long day.
The NREM stages are important for restoring energy, which is most likely why they are the ones that come first.

An image of a man sleeping naked.

4. NREM stage has three phases lasting four to six hours every night, whereas the REM stage lasts up to two hours.

As we have just learned, we cycle through stages of sleep each night several times. Four to six times – depending on how long we sleep and how long they last.

The REM stage usually occurs about 90 minutes after you fall asleep, and it lasts for about 20-30 minutes. During this stage, your eyes move rapidly from side to side, and your brain activity increases. You may also dream during this stage. Overall, you may end up with up to two hours of REM sleep each night.

On the other hand, the NREM stage is divided into three phases:

Phase 1: This is the lightest stage of sleep, and it usually only lasts for a few minutes- one to five to be precise. Your eyes are closed, but you can still be awakened easily.
Phase 2: This is a slightly deeper stage of sleep (although deep sleep), and it lasts for about 20 to 30 minutes, although it can last anywhere between 10 and 60 minutes. This is the stage you spend most of your time in during the night.
Phase 3: This is the deepest and most restful stage of sleep. It usually lasts for about 30 minutes. During this stage of sleep, you can't be awakened easily, and if you were, you would probably have a hard time coming to your senses.

Overall, these three NREM stages add up to about four to six hours every night.

5. NREM uses significantly less energy than REM sleep.

During non-rapid eye movement (NREM) sleep, your brain activity and muscle activity slow down. Your heart rate and breathing also slow down. NREM makes up about 75% of your total sleep time.

During rapid eye movement (REM) sleep, your brain activity is similar to when you are awake. Your muscles are also active, but your body is “paralyzed”. Your heart rate and breathing increase during REM sleep. REM sleep makes up the other 25% of your total sleep time.

As a result, NREM sleep uses less energy than REM sleep because your brain and body are not working as hard. Although NREM and REM sleep both use less energy than being awake, NREM sleep uses even less energy than REM sleep.

An image of a young man sleeping in a deep sleep phase.

6. REM stage is a crucial part of keeping our brain in good condition (in every sense)

REM sleep is important because it helps to consolidate memories. This is because, during REM sleep, the brain is highly active and connects newly learned information with previously stored information.

This helps to improve our memory and recall abilities. REM sleep is also thought to help us process and understand new information better by stimulating the areas of our brain responsible for learning.

REM sleep also helps to improve our mood and increases creativity. Finally, REM sleep is also associated with the increased production of certain proteins.

7. Different age groups experience the NREM/REM stages longer/shorter

As we grow older, our need for sleep diminishes. Newborns require the most sleep, averaging 16 hours per day. By the time we reach adulthood, we need only about 7 or 8 hours of sleep a day. And, as we enter the late stages of our life – most of us can get by with five to six hours of sleep each day.
The amount of time spent in each stage of sleep also changes with age.

An image of a baby wearing a hat while sleeping.

Newborns spend 50% of their sleeping time in REM sleep and 25% in each of the other three stages.

As we age, we spend less time in REM sleep and more time in the other two stages. By the time we reach adulthood, we spend about 20% of our sleep in REM sleep and 40% each in stages 1 and 2 (mostly 2).

Age also affects how long it takes to fall asleep. It generally takes longer for older adults to fall asleep than younger adults, increasing the time they spend in the early stages of sleep as opposed to late, deep sleep stages.

Recommended reading:

Comments (0)

There are no comments yet

Related Posts

Articles you don’t want to miss

Featured image for mattress cover 101
07 November 2023

Mattress Cover 101

While you might find a wide selection of mattress covers, what you get can differ slightly depending on the store or website you get it from...
Featured image for Sofa beds with storage
01 November 2023

Sofa Beds With Storage: The Ultimate Guide

Some sofa beds will have two separate parts, with the "bed section" on top and independent drawers on the bottom. This means that figuring o...
Don't Miss Out!
Get the latest reviews, special offers, new releases and more…
Deal Alert!
We loved this Deluxe microfibre duvet from Otty. And we love it more now that it's on Black Friday sale!
Hit the link in bio to check this deal and all the rest this Black Friday

#DealAlert #BlackFridaySale #MicrofibreDuvet #Otty #DeluxeQuality #SleepInStyle #ComfyBedding  #LuxurySleep #BlackFridayDeals #Discounts #ShopTillYouDrop #BedroomUpgrade #HomeDecor #CozyNights #SleepWell #BedroomGoals #LimitedTimeOffer #SaveBig #BestDeals #OnlineShopping #BargainHunting #MustHaveItem #SaleAlert  #SleepInComfort #BudgetFriendly #ShopSmart #DuvetLove #BlackFridaySpecials  #GetItWhileItsHot #HomeComforts
Shhhh.... I'll tell you a secret! Black Friday isn't over!
We've rounded up the stragglers to cater for your Black Friday FOMO. 
Mattresses, Beds & Bedding are still on MAJOR discounts, so don't delay! Get a bargain today.

Links in bio

#BlackFriday #SecretDeals #MattressSale #BedSale #BeddingSale #Discounts #Bargains #BlackFridayFOMO #MajorDiscounts #StillOnSale #LimitedTimeOnly #DealAlert #ShopSmart #SaveMoney #SleepBetter #QualitySleep #LuxuryBedding #ComfortableMattress #GoodNightSleep #BedroomUpgrades #HomeDecor #InteriorDesign #HappyCustomers #OnlineShopping #Convenience #LinkInBio #Don'tMissOut #ShopNow #GetABargain #GreatDeals
Mattress Deal Alert! 
Here are some top value deals we've sniffed out for you this Black Friday!
We love these from Emma, but they're not all! Check our Black Friday deal summary for all the best bed and mattress deals to save you money and upgrade your snooze this Black Friday!

#MattressDealAlert #BlackFriday #TopValueDeals #EmmaMattress #BlackFridayDeals #BedDeals #MattressDeals #SaveMoney #UpgradeYourSnooze #BestDeals #SleepBetter #SnoozeBetter #BlackFridayShopping #Bargains #BigSavings #HotDeals #LimitedTimeOffer #Discounts #SaleAlert #SleepComfortably #SaveBig #MustHaveDeals #BlackFridaySales #GreatOffers #DreamBedroom #ComfortableSleep #BudgetFriendlyDeals #QualityMattress #SleepHappy
Best Mattresses With Edge Support UK – Top 5 Picks Reviewed 💤

The best mattress with edge support UK has to offer is… Well, let's not get that ahead of ourselves. First, let's understand what edge support is and why it might be important to you!  Check out the link in BIO🔗

#thesleepadvisors #sleep #sleeping #edgesupport #mattresses #topmattresses
Don't snooze! Well.... not yet! First pick up a bargain in the Black Friday sales! 
We've rounded up all the best deals to save you searching. You can find them all at the links in bio... then snooze your little socks off!

#BlackFridayDeals #BargainHunting #Savings #DealFinder #BlackFridaySales #ShopTillYouDrop #Discounts #BestDeals #LimitedTimeOffers #BigSavings #MoneySavingTips #OnlineShopping #SalesAlert #HolidayShopping #ShopSmart #ShopOnline #EarlyBirdGetsTheDeal #MustHaveItems #HolidayGifts #ShoppingSpree #Don'tMissOut #ClearanceSale #BiggestSaleOfTheYear #GetThemandSave #ScoreABargainGiveaway
Do you sleep on your tummy? On the side? Or on your back?
Can a topper suit your sleeping position & improve your sleep?
With 15% Off for Black Friday, the Panda Mattress Topper is worth a try!

#thesleepadvisors #topper  #mattresstopper #saggymattress #panda #sleepingpositio
Beat the queues and get your black Friday shopping done early!
You won't miss out as we've pulled this year's best deals together in one handy page. You'll find it on the link in bio

#blackfridaydeals #blackfridaysale #mattress
You can make or break your bedroom style with the perfect bed! What can make this easier? A HUGE Black Friday discount on your chosen bed frame of course!
From Ottoman to Sofa Beds, Metal or Wooden. The Sleep Advisors have pulled together the best in beds this Black Friday and here they are.
Link in bio

#bedroomstyle #perfectbed #BlackFridaydiscount #bedframe #Ottomanbeds #SofaBeds #Metalbeds #Woodenbeds #SleepAdvisors #bestinbeds #BlackFridayDeals #FurnitureSale #interiordecor #comfortablebed #sleepwell #homeimprovement #dreambedroom #discountshopping #shoppingtime #homefurnishings #cozybedroom #interiordesignideas #bedroominspo #masterbedroom #comfybedroom #sleepingbeauty #bedroomupgrade #relaxationstation #styleandcomfort #sweetdreams
Black Friday deal alert!
Get 15% discount on the award-winning Panda Hybrid Bamboo Mattress Topper!

#BlackFriday #DealAlert #Discount #PandaHybrid #BambooMattress #MattressTopper #SleepBetter #BedroomUpgrade #LuxurySleep #Sale #LimitedTimeOffer #SleepComfortably #SaveMoney #QualitySleep #ComfortableBedding #NaturalMaterials #SustainableChoice #EcoFriendlyMattressTopper #AffordableLuxury #BestPrice #HolidayShopping #HomeDecor #GreatDeal #BlackFridaySale #LimitedStock #InnovativeDesign #PremiumQuality #SleepWell #CozyBedding #BetterSleepingExperience
Do you sleep on your tummy? On the side? Or on your back? Can a topper suit your sleeping positions, and improve your sleep? Let’s find out! Check out the link in our BIO
#thesleepadvisors #topper #mattresstopper #saggymattress #panda #sleepingposition
Close button

Don't Miss Out!

Get the latest reviews, special offers, new releases and more…

By submitting this form, you are opting into our mailing lists.
See our privacy policy.

This field is for validation purposes and should be left unchanged.