REM Sleep explained
From sleep hygiene before bedtime to the various stages of sleep we cycle through each night, it can be overwhelming to pinpoint strategies you can use to improve your sleep. That’s why we’re diving into a crucial part of your sleep cycle - REM sleep.
You’ve probably heard of rapid eye movement (REM) sleep as the time of the night when you dream, but REM is also the stage of sleep that can improve your memory, learning skills, and mood.
And even though healthy adults only spend about 20 to 25% of their total sleep time in REM, it’s a key factor in helping you feel alert and well-rested for the next day.
We’re diving into the REM sleeping stage to uncover why it’s so important to your overall health and what you can do to make sure you’re spending enough time in REM.
REM Sleep 101: What You Need To Know
What is REM Sleep? Rapid eye movement sleep is the most active of the four sleep stages we cycle through every night, which is why you may also hear it referred to as “paradoxical” sleep. During this stage, eyes move rapidly behind eyelids (hence the name rapid eye movement). Brain activity, heart rate, and breathing quicken. Most muscles also become temporarily paralyzed to prevent you from acting out dreams and accidentally hurting yourself (thank you, evolution).
As we’ve mentioned, REM sleep not only helps us dream but strengthens our emotional processing, creativity, memory consolidation, and brain development. It also helps regulate our mood when we’re awake.
You’ll usually hit your first period of REM sleep 90 minutes into the night, after passing through the first NREM (non-REM sleep) stages. At the beginning of the night, REM stages last around 10 minutes and can increase to up to an hour.
The Stages of Sleep
We’ve touched on sleep cycles a bit, and in this section, we’ll talk more about them. Sleep cycles are usually made up of NREM and REM sleep.
Humans move through different stages of both NREM and REM sleep several times throughout the night, with REM sleep becoming longer as the night goes on.
NREM sleep can be further broken down into three stages: N1, N2, and N3. These are sometimes referred to as light sleep, moderate sleep, and deep sleep. Most people spend around 50 to 60% of their sleep time in NREM stages N2 and N3.
N1: light sleep
This is the stage between wakefulness and sleep. Your eye movement slows and your muscles relax. You may also experience hypnagogic hallucinations at this stage, which are brief vivid images or sensations that can occur as you are falling asleep.
N2: moderate sleep
This is a lighter stage of sleep where your eye movement stops and your muscles relax even further. Your heart rate and breathing also begin to slow. During this stage, you may be difficult to wake up.
N3: deep sleep
This is the deepest stage of sleep. Your muscles are now fully relaxed and your heart rate and breathing are at their slowest. It becomes more difficult to wake someone during this stage of sleep.
Below, we discuss the fourth and final stage of sleep - REM sleep.
REM Sleep, Brain Activity, and Our Body
Because of all the activity happening in your brain during REM, it’s rightfully earned the nickname of “paradoxical” sleep.
This is because although your brain is more active than during NREM sleep, your body is actually more relaxed - to the point of paralysis in some cases. EEG scans have shown that your brain waves look similar during this stage of sleep to the brain waves you have when you’re awake.
Let’s dive deeper. The brainstem is responsible for sending messages to the rest of your body to enter different sleep stages. During REM sleep, the brainstem signals the cortex (the part of your brain responsible for processing information) to become more active. The cortex is where our thoughts, memories, and emotions are formed.
This is also the part of our brain that’s responsible for processing the information we take in from the world around us. From the cortex, messages are then sent to the thalamus.
The thalamus is sort of like a switchboard, relaying information from the cortex to the rest of the brain. When we’re awake, the thalamus is very active, sending messages to our senses so that we’re constantly taking in information from the world around us.
During REM sleep, the thalamus becomes more active, sending messages to the cortex. This is why we often have very vivid dreams during this stage of sleep. During NREM sleep, the thalamus is less active, which is why our dreams are typically less vivid and more difficult to remember.
As mentioned earlier, most of our muscles are also paralyzed during REM sleep. The exception is the muscles that control our eye movement and our breathing.
The paralysis of our muscles during REM sleep is actually a good thing. It’s there to prevent us from acting out our dreams and hurting ourselves. Our body temperature also drops during this stage of sleep, which helps to further promote muscle relaxation.
REM Sleep: Getting Enough is Important
Though REM is only one stage in the sleep cycle, studies have shown that not getting enough REM sleep can interfere with memory formation and hurt your brain’s ability to generate new cells. The amount of time spent in REM will be dependent on factors like age, sleep schedule, and sleep hygiene. We do know that on average, adults will spend about 20 to 25% of the night in REM.
Don’t worry - you don’t have to know exactly how much REM sleep you’re getting every night to improve your sleep. Instead, experts recommend focusing on getting an overall sleep time of 7 to 9 hours per night. The number of hours you spend in each stage of sleep will vary from night to night, but as long as you’re getting enough total sleep, you’re likely getting the REM sleep you need.
In general, sleeping less than 7 hours during a 24-hour period has been shown to reduce the amount of REM you get. According to the Sleep Foundation, people who get less than 6 hours of sleep per night experience the same kind of memory problems as people who haven’t slept for 2 nights in a row. This is probably due to the fact that you get the most REM sleep at the end of the night, and if you’re not sleeping for as long it reduces your chances of hitting an adequate amount.
Benefits of Enough REM Sleep
REM sleep has been shown to offer a number of benefits, both cognitive and physical. We mentioned some of them and below, we break them down:
Helps with Emotional Processing
When you’re going through a tough experience, it can feel like your thoughts are stuck on repeat. This is because you haven’t had the chance to process the emotions associated with the event.
A study discovered that how well and how much we sleep is integral to our reaction to emotional events, overall health, and well-being. It was found that not getting enough sleep leads to an amplified startle response and less dream recall. Furthermore, research showed that a lack of sleep can make it harder to fall asleep or stay asleep during REM cycles–and when we do enter into REM sleep, we spend more time there than usual.
Sometimes, creative people think they do their best work when they’re up late at night. This might be because they’re more likely to have higher levels of creativity if they’re sleep-deprived. However, this is only true up to a certain point. After a certain amount of sleep deprivation, creativity levels will drop.
This is where REM sleep comes in - getting enough of this stage of sleep can actually improve your creativity. A Cardiff University study found that REM sleep and non-REM sleep are both essential for creative problem-solving. The two stages work in unison to help us find undiscovered relationships between what we already know and identify unique solutions to difficult problems.
Memory Consolidation and Formation
There are different types of memory, but the two main ones are declarative and procedural. Declarative memory is what we use to remember facts and events. This includes things like the name of your first-grade teacher or what you had for breakfast yesterday.
Procedural memory, on the other hand, is what we use to remember how to do things. This includes things like riding a bike or tying your shoes.
While there is no clear consensus on the role of REM sleep in memory consolidation, there is some evidence to suggest that it plays a role. Both REM and NREM sleep have been found to be important for declarative memory consolidation.
A wealth of literature indicates that the emotional aspect of memories is dependent on REM sleep for solidification. This is supported by research that suggests that “emotional arousal during encoding is beneficial to recall only if REM sleep occurs after learning.”
Chronic inflammation has been linked to a number of health problems, including heart disease, arthritis, and Alzheimer’s disease. While there are a number of things you can do to reduce inflammation, getting enough REM sleep is one of them.
That is why doctors often recommend that people with chronic inflammation get more sleep. According to Harvard research, sleep deprivation is associated with markers of inflammation, such as increased levels of C-reactive protein and interleukin-6. A lack of sleep can also make existing inflammation worse, even if you’re otherwise healthy.
When We Don’t Get Enough REM Sleep
At this point, you know how important REM sleep is. But what happens when we don’t get enough of it? Unfortunately, not getting enough REM sleep can have a number of negative consequences.
Below, we’ll take a look at some of the most common ones.
Irritability and Moodiness
If you’ve ever been sleep-deprived, you know that it can make you feel irritable and moody. This is because not getting enough sleep can throw off your body’s levels of the hormones serotonin and dopamine. These hormones are responsible for regulating mood.
Notice that we said “can” make you feel irritable and moody. That’s because not everyone will react the same way to sleep deprivation. Some people might become more emotional, while others might become less emotional.
Difficulty Concentrating and Paying Attention
Focusing on a task can be difficult when you’re tired. This is because not getting enough sleep can lead to what’s known as “cognitive fatigue.” When you’re cognitively fatigued, your brain has a hard time processing information and making decisions.
A lack of REM sleep can also make it hard to pay attention. This is because, during REM sleep, the brain consolidates memories and creates connections between different ideas. When you don’t get enough REM sleep, these connections aren’t made, and it can be hard to focus on tasks.
Anxiety and Depression
Anxiety and depression are two common mental health disorders that are often treated with sleep. That’s because not getting enough sleep can worsen symptoms of both disorders.
Researchers found that people with anxiety were more likely to have sleep problems. It’s believed that not getting enough sleep can increase anxiety by making it hard to focus and by increasing levels of the stress hormone cortisol.
Not getting enough sleep can also worsen symptoms of depression. When we’re depressed, we’re less likely to want to do things that make us happy. This can include activities like exercise and socializing. Not getting enough sleep can also make it hard to concentrate and make decisions.
Decreased Immune Function
Our body’s immune system helps us fight off infection and disease. But when we don’t get enough sleep, our immune system doesn’t work as well. As we sleep, our body produces immune cells and proteins. These help us fight off infection. When we don’t get enough sleep, we produce fewer of these cells and proteins, making us more susceptible to illness. For example, it has been found that people who slept less than seven hours a night were more likely to catch a cold than people who slept eight hours or more.
Sleep Disorders and REM Sleep
There are a number of different sleep disorders that can cause someone to wake up during REM sleep. These disorders include narcolepsy, sleep apnea, and restless leg syndrome. When someone has one of these disorders, they might not get enough REM sleep.
Narcolepsy causes people to fall asleep suddenly and unexpectedly. This can happen during the day or at night. People with narcolepsy often have trouble staying asleep for more than a few hours at a time.
This is another disorder that can cause people to wake up during REM sleep. This disorder causes people to stop breathing for short periods of time during sleep. These pauses can last for a few seconds or minutes. People with sleep apnea often snore loudly.
Obstructive sleep apnea is the most common type of sleep apnea. It’s caused by a blockage in the airway, such as from obesity or enlarged tonsils.
Restless Leg Syndrome
If you have restless leg syndrome, finding a comfortable position to sleep in can be difficult. This disorder causes people to feel the need to constantly move their legs, which can happen when they’re sitting or lying down for long periods of time. Moving around may help ease this sensation temporarily, but it also makes it hard to get a good night’s rest.
Other sleep disorders include insomnia, bruxism, and sleepwalking. These disorders can also make it hard to get enough REM sleep, or can worsen symptoms of other disorders.
Any sleep disorder that prevents you from getting a good night’s sleep can make it hard to focus and pay attention during the day. If you think you might have a sleep disorder, talk to your doctor.
Neurological Disorders and REM Sleep
Other than sleep disorders, there are a number of neurological disorders that can cause someone to wake up during REM sleep. These include Parkinson’s disease, Alzheimer’s disease, and multiple sclerosis.
And then there’s REM sleep behavior disorder.
REM Sleep Behavior Disorder: What You Need to Know
REM sleep behavior disorder (RBD) is a condition that causes people to act out their dreams. People with RBD may kick, punch, scream, or shout during their sleep. They may even get out of bed and walk around.
The causes of RBD are not fully understood, but it’s believed to be linked to changes in the brain. Some research suggests that RBD is caused by changes in the brainstem, which controls sleep.
RBD can occur at any age, but it’s most common in middle-aged and older adults. It’s more common in men than women. RBD is a serious condition that can lead to injury. It’s also been linked to neurodegenerative diseases, such as Parkinson’s disease and Lewy body dementia. The symptoms of RBD can be treated with medications.
How To Make Sure You’re Getting Enough REM Sleep
It’s hard to track exactly how much REM sleep you’re getting per night. Some side effects of a lack of REM sleep include anxiety, aggression and irritability. Research also suggests that a lack of REM can cause migraines and decreased mental sharpness. Some ways to improve REM sleep include avoiding alcohol before bed, following a consistent sleep/wake schedule, and avoiding screens before bed time (or try wearing blue light glasses).
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Frequently Asked Questions (FAQs)
Why do I feel restless after getting a full night’s sleep?
Sleeping for a full eight hours doesn’t necessarily mean you’ll wake up feeling rested. A number of factors can contribute to feelings of fatigue, including poor sleep quality, sleep disorders, and underlying health conditions. If this happens on a regular basis, it’s a good idea to talk to your doctor.
How can I tell if I’m getting enough REM sleep?
There’s no easy way to track how much REM sleep you’re getting. However, there are a few signs that you may not be getting enough, including daytime fatigue, anxiousness, and irritability. If you’re concerned about your REM sleep, talk to your doctor.
Is there anything I can do to improve my REM sleep?
There are a few things you can try to improve your REM sleep. Avoiding alcohol before bed, following a consistent sleep/wake schedule, and avoiding screens before bedtime can help. You can also try wearing blue light glasses. If you have a sleep disorder, treatment can help improve your REM sleep.
What is the difference between REM sleep and deep sleep?
REM sleep is a lighter stage of sleep that’s characterized by rapid eye movement. Deep sleep is a deeper stage of sleep that’s characterized by slow eye movement. Deep sleep is also known as slow-wave sleep. Both REM and deep sleep are important for overall health.
What is the difference between REM sleep and dreaming?
REM sleep is a stage of sleep that’s characterized by rapid eye movement. Dreams occur during any stage of sleep, but they’re most likely to occur during REM sleep. Dreams are a normal part of sleep and are often bizarre or surreal. They’re believed to be a way for the brain to process information and sort through memories.
Can I die from a lack of REM sleep?
There is no direct evidence that a lack of REM sleep can kill you. However, REM sleep is important for overall health. A number of studies have linked a lack of REM sleep to serious health conditions, such as heart disease, stroke, and diabetes. A lack of REM sleep can also lead to daytime fatigue, anxiety, and irritability. If you’re concerned about your REM sleep, talk to your doctor.
How much REM sleep do I need?
There is no one-size-fits-all answer to this question. Depending on your age and health, you may need more or less REM sleep. Most people need around 20-25% of their total sleep time to be in REM sleep.
What are the signs of normal sleep?
There are a few signs of normal sleep, including:
- Falling asleep within 30 minutes of going to bed
- Waking up feeling rested
- Falling asleep and staying asleep for 7-9 hours
- Feeling alert and energetic during the day
Your physical and mental health can also affect your sleep, so it’s important to talk to your doctor if you’re having trouble sleeping.
Can I treat sleep deprivation at home?
There are a few things you can try to treat sleep deprivation at home, including:
- Establishing a regular sleep schedule
- Practicing relaxation techniques
- Creating a sleep-friendly environment
- Avoiding caffeine and alcohol before bedtime
If these home remedies don’t work, talk to your doctor. You may need to be treated with medication or therapy.
Will my insurance cover treatment for sleep deprivation?
It depends on your insurance plan. Some plans may cover treatment for sleep disorders, while others may only cover treatment for underlying health conditions that cause sleep deprivation. Check with your insurance provider to see what’s covered under your plan.
How can I find a sleep specialist?
You can search for a sleep specialist in your area through the American Academy of Sleep Medicine’s website or your country’s sleep medicine society. You can also talk to your primary care doctor or a local hospital to find a sleep specialist.
Can I take sleeping pills for sleep deprivation?
Sleeping pills can help you fall asleep, but they don’t always help you stay asleep. And they can have side effects, such as daytime drowsiness and dizziness. If you’re considering taking sleeping pills, talk to your doctor first. They can help you determine if sleeping pills are right for you and, if so, what kind to take.
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