How many stages of sleep are there? 3, 2, 1…drift off
Who has time for sleep these days, right?
You’re constantly racing from one challenge to the next in your life, handling tasks at work and dealing with things at home. Sleep probably gets pushed to the very back of your to-do list most days.
However, catching your forty winks isn’t just about letting your body shut down for a bit until your alarm goes off each morning. Sleep is a complicated cycle of stages that helps to protect your health and repair your body every night.
The stages of sleep are crucial to your internal clock, and they’re there to help you regulate patterns of brain waves that control everything from your energy levels to your metabolism.
So, how many stages of sleep are there — and why are they so important?
Well, according to most scientists, there are somewhere between four and five sleep stages that occur every ninety minutes that you’re in bed. So in a way, you go to sleep about four to six times every night. The amount of time you spend in any specific sleep stage will determine how fully rested you feel the next day.
Let’s take a dive beneath the covers and discover what’s going on when you close your eyes at night.
What are the five stages of sleep, and why do they matter?
So, what are the sleep stages, and what do they mean to you?
Well, you probably already know that your body goes through various phases when you’re sleeping. You’re not just blacked out until morning. Instead, you’re going through a hyper-intelligent process of recuperation and growth — kind of like a computer updating before you switch it on again.
Depending on how you look at them, there are 4-5 different stages of sleep that the body goes through, which break down even further into REM sleep, and NREM (Non-REM) rest. REM stands for “rapid eye movement,” we’ll come back to that in a minute.
So, what sleep stages are most important?
Truthfully, they all have a role to play in your health and wellness:
Stage 1 sleep is when you’re floating in and out of consciousness — not fully awake or asleep.
Stage 2 sleep is when you begin to enter lighter phases of sleep, and your muscles, heart rate, and brain activity all start to relax.
Stage 3 & 4 sleep are often combined in most medical circles. Known as slow wave sleep (SWS), they’re the deepest part of the sleep cycle, where you’re more likely to experience sleepwalking.
Stage 5 sleep is REM sleep, the stage you associate with dreaming. It’s also the shortest phase in the sleeping cycle.
What happens during sleep stages?
By this point, you’re probably starting to see how sleep stages work and why they’re so valuable.
However, there’s still more to learn about what happens during sleep stages and how your body responds to the changing cycle of your circadian rhythm.
Let’s break down the basics of each of the sleep stages one by one.
Stage 1 sleep
Otherwise known as NREM stage 1, the first stage of sleep is the transitional phase between consciousness and unconsciousness. During this stage, your brain waves are shifting from alpha waves to theta waves — the kind of brain waves you get during meditation or deep relaxation.
During this stage of sleep, you’ll probably feel drowsy, but it’ll be easy enough to wake you up with movement or a loud noise. This is also the stage of sleep where you experience jolts in your muscles that make you feel like you’re suddenly falling.
Although you’re only supposed to spend about 5% of your sleep in stage 1, if you suffer from insomnia, you might be in this stage for much longer.
Stage 2 sleep
In the second of the sleep stages, you’ll be starting to relax on a more physical level, with your heart rate reducing and your breathing slowing gradually. Your body temperature is also likely to start decreasing. Eye movement also stops, except for quick bursts of motion known as sleep spindles.
It’s still possible to wake someone up through NREM stage 2. However, they’re more likely to know that they were sleeping. You spend around 50% of the sleep cycle in this stage, which can last for about 20 minutes.
Wondering what sleep spindles are? They’re bursts of activity in the brain that may be connected to the mind’s ability to absorb new information. Studies suggest that the more sleep spindles you experience when napping, the more likely you are to retain further information.
Stage 3 sleep and stage 4 sleep
The 3rd and 4th sleep stages are so similar that they’re usually combined into the same phase. That’s why some scientists refer to their being 4 stages of sleep, while others say that there are 5 full phases. It all depends on your approach.
Stage 3 and 4 sleep are periods of “short wave sleep.” These periods are when slow delta brainwaves begin to occur within your mind, and your blood pressure starts to drop. It’s tough to pull someone out of these stages of sleep — and even if you do, it’s not necessarily good for them. Most people who wake up during deep sleep periods are groggy and disoriented.
When it comes to how sleep stages work, the 3rd and 4th phases are some of the most important, because they affect how your body repairs itself, and can last for up to an hour. During this period of sleep, you also release human growth hormone, or HGH, which helps you to strengthen your muscles and mind. Deep sleep stages are also crucial for your immune system. However, during stage 4 sleep and stage 3, you’ll be more exposed to things like nightmares.
Stage 5 sleep — REM sleep
Ask anyone what the five stages of sleep are, and they’re sure to guess that at least one is “REM” sleep.
This is the best-known phase of sleep that your body goes through each night, even though it’s also one of the shortest stages. REM sleep or rapid eye movement rest is when you dream, and your brain activity begins to increase, along with your blood pressure and heart rate.
REM sleep is crucial for preserving your memory, improving your emotional health, and honing your survival instincts. That’s why scientists agree that it’s not just sleep deprivation that can cause serious repercussions for people today — but dream deprivation too.
Is REM sleep the most important?
So, what sleep stages are most important?
One thing you need to remember here is that there are multiple different sleep stages for a reason. They all work together to give you the kind of rest you need to tackle each day of work, play, and so on. While it’s true that stage 1 sleep and stage 2 sleep might not be quite as valuable as deeper phases of rest — they’re still crucial to your pattern.
While deep sleep stages (3 and 4) are most important to your nightly rest and making sure that you feel recuperated in the morning, it’s the REM sleep cycle that may matter most to your long-term health. This stage starts about 80 minutes after you fall asleep. Most of the time, you’ll switch out of a deep sleep period with a few moments in stage 2 sleep, before moving into stage 5 sleep.
During REM sleep, your brain waves are very similar to the activity you have when you’re aware. This is the time when the most intense dreaming occurs. Even if you don’t remember your dreams, the presence of REM in every sleep cycle means that there’s no such thing as a healthy person who “doesn’t dream.” However, children can spend longer in REM sleep than adults.
When a healthy person is in REM sleep, their muscles and body are deeply relaxed — which is crucial to keeping your body safe. This is one of the reasons why some people experience stages of paralysis if they’re woken up during stage 5 sleep. Interestingly, people with Parkinson’s disease don’t always experience this paralysis during REM sleep, which means that they start to act out their dreams in some cases.
Of all the stages of sleep, REM seems to have the most significant benefits. Similar to the deep sleep stage, REM helps to restore and heal the body. It also stimulates the brain, helping to retain memories and record new lessons learned throughout the day. Just like in deep sleep, stage 5 sleep also improves the production of crucial proteins that are highly beneficial for body growth. REM sleep has even been linked to pain relief. Patients who get good sleep sessions typically experience less pain when recovering than people who struggle to sleep.
You really can “sleep it off.”
How are sleep stages measured?
So, how do we know what sleep stages are normal? How is it possible to measure the amount of time that we get in any given stage through the night?
Until very recently, it was difficult to gather any information on the stages of sleep without hooking a patient up to countless electrodes and monitors. Now, however, there are apps and wearable devices that can track sleep by measuring heart rate and pulse. This makes it easier for the average person to track their sleep stages and make sure that they’re getting quality rest.
You can also consider speaking to a doctor if you’re worried about the different stages of sleep. If you think that disruptive sleep is causing problems for your health, then your doctor can send you for an advanced sleep study in a lap. Here, scientists attach electrodes to your body and head to see exactly what’s going on in each of your stages of sleep.
When you can read the stages of sleep that your body experiences with machine read-outs and insights, then you and your doctor can create a sleep stages chart that help to guide you through the kind of sleeping phases that are missing from a good night’s rest. Psychologists can then refer to your sleeping chart to determine effective psychological strategies that might contribute to a better night of sleep.
How much time do you need in each sleep stage?
When people talk about not getting enough sleep, they’re often referring to the inability to get enough stage 3, 4, and 5 rest. These are the deeper stages of sleep when most of your body’s recovery and growth happens. Deep sleep is responsible for helping you to process information each day. If you don’t get enough sleep, you can’t remember things as well. Additionally, a lack of quality sleep is linked to heart disease, stroke, diabetes, and Alzheimer’s disease.
It’s easy enough to say that the average adult needs 7 or 8 hours of sleep per night. But how do you divide that time up into the different sleep stages? Generally, you’ll need to sleep around 75% of your night in non-REM sleep, and 25% in REM sleep. Only about 23 percent of your sleep in total is actually in a deep sleep.
The amount of sleep you need (and get) decreases with age. If you’re under the age of 30, you’re likely to get at least two hours of deep sleep each night. On the other hand, people over the age of 65 rarely get a lot of deep sleep. Although there’s no one-size-fits-all guide to the perfect sleeping cycle, it’s safe to say that most people need at least some restful sleep each night to help them prepare for the challenges ahead. Here’s a look at the sleep stages by age:
Newborn to 4 months: Sleep is pretty much entirely REM sleep — with a few periods of “quiet,” non-REM sleep.
4 months to 1 year: Sleep is more consolidated — about 13 hours per day, with plenty of REM sleep (around 50% or above).
1 year to 3 years: As sleeping patterns start to develop, children spend more time in stage 3 or 4 deep sleep, with about 25% of their time in REM. Usually, they’ll sleep for about 10.5 hours a day.
3 years to 6 years: During this time, stage 3 or 4 sleep is the most common type of rest, and usually, toddlers begin to sleep less (around 10 hours per day).
6 years to 12 years: The amount of time spent asleep remains unchanged, and stage 3 and 4 sleep makes up about 20% of sleep time.
12 and up: The amount of sleeping time needed reduces consistently throughout your life, making it harder to “sleep in” in the morning. You can regulate your sleeping patterns to around 7 hours per day.
Perfecting the stages of sleep: FAQ
Ultimately, it’s difficult to control the stages of sleep — no matter how hard you try.
Even with medication and a great sleep hygiene strategy, there’s always a risk that you won’t be able to get the right amount of stage 3, 4, and 5 sleep to ensure better restfulness and a healthy mind. However, your doctor can help you to enhance your sleep strategy by guiding you through how sleep stages work, and what you need to do to support them.
Here are some quick insights into the world of sleep cycles if you have any remaining questions:
Q: Sleep stages by age: Do stages differ by age?
A: You’re more likely to get plenty of deeper sleep as a child than you are as an adult. Unfortunately, the older you get, the easier it is for stress and other issues to keep you in stage 1 and 2 of your sleep cycle for longer than necessary. This can also cut down on the amount of restful and deep sleep that you get each night. Newborns spend about half of their total time asleep in REM because they need to spend more time growing and developing. Babies also have shorter sleep cycles but can fall straight into REM, rather than spending time in stage 1 and 2.
Q: How many stages of sleep are there?
A: This question depends on who you ask — most scientists agree that there are either four or five stages of sleep.
Q: What are the different stages of sleep?
A: The different stages of sleep include light sleep (NREM), which happen during phases one and two, (SWS) or short wave sleep, which occurs during stages 3 and 4, and REM sleep, which occurs during stage 5.
Q: How long do sleep stages last?
A: Most of your sleep will happen in stages 3 and 4 — which is the deep sleep portion of your sleep cycle. Though the length of each stage can vary, most cycles last for around 90 minutes, with only a few minutes dedicated to stages 1 and 2, and a few minutes available for REM sleep.
Q: What sleep stages are the most important?
A: All sleep stages are essential. However, what happens during sleep stages can make some phases more valuable than others. For instance, REM sleep and deep sleep are crucial to your wellbeing and long-term health.
Q: How do sleep stages work during napping?
A: While sleep stages might make you feel better at first, you should ensure that you get a full 90- minute sleep cycle if you can. Some people say that 15-20 minutes of napping is great because it’s harder to get out of your nap when you’re further along in your sleep schedule.