Understanding Sleep: Light, Deep And Rem Percentages

Sleep is divided into two categories: REM (rapid eye movement) and non-REM sleep. While the quality and quantity of sleep are both important, the amount of time spent in each stage of sleep can have a significant impact on how restorative it is. Sleep occurs in cycles, and each cycle includes different stages of sleep. Light sleep, deep sleep, and REM sleep are the three stages of sleep. Each stage has a distinct purpose and contributes to overall health and well-being in different ways.

The ideal percentage of light, deep, and REM sleep

Sleep is divided into two categories: REM (rapid eye movement) and non-REM sleep. There are three NREM stages. When you fall asleep, you enter NREM stage 1 and then cycle between NREM stages 2 and 3. After that, you go into REM sleep and start dreaming. After the first REM cycle, you start a new sleep cycle and go back into stage 1 or 2, and the cycle starts over.

One cycle normally takes about 90 to 120 minutes, and most people go through four or five cycles per night (assuming they get a full eight hours of sleep).

Stage 1 NREM Sleep

Stage 1 NREM sleep is the lightest stage of sleep. You enter stage 1 right after you fall asleep. This stage usually lasts only a few minutes, making up about 5% of your sleep time. After that, your sleep gets deeper, and you move into stage 2 NREM sleep.

Stage 2 NREM Sleep

Stage 2 is still light sleep, but deeper than stage 1. Your brain waves slow down and have noticeable pauses between short, powerful bursts of electrical activity. Experts think that these bursts are your brain organizing memories and information from the time you spent awake.

Stage 2 NREM sleep accounts for about 45% of your time asleep (the most of any stage). You’ll go through multiple rounds of stage 2 NREM sleep, and usually, each one is longer than the last. After stage 2, you move deeper into stage 3 NREM sleep or enter REM sleep.

Stage 3 NREM Sleep

The deepest stage of NREM sleep is stage 3. It makes up about 25% of your total sleep time in adults. But babies and children need more stage 3 sleep, and the older you get, the less you need.

In stage 3, your brain waves are slow but strong. Your body takes advantage of this very deep sleep stage to repair injuries and reinforce your immune system.

You need stage 3 NREM sleep to wake up feeling rested. Without enough stage 3 sleep, you feel tired and drained even if you slept for a long time. That’s why your body automatically tries to get as much stage 3 sleep into your sleeping period as early as possible.

Because stage 3 NREM sleep is so deep, it’s hard to wake someone up from it. If they do wake up, they’ll probably have “sleep inertia,” a state of confusion or “mental fog” that lasts about 30 minutes.

REM Sleep

REM sleep makes up about 20 to 25% of your total time asleep. Your first REM cycle of a sleep period is typically the shortest, around 10 minutes. Each one that follows is longer than the last, up to an hour.

REM sleep is when most dreaming happens. Your eyes move rapidly in different directions (hence the name). Heart rate increases and your breathing becomes more irregular.

REM sleep is very important for emotion regulation and memory—you’re clearing the brain of things that aren’t needed, and it’s also the peak of protein synthesis at the cellular level, which keeps many processes in the body working properly.

There is no one-size-fits-all answer to this question as the ideal percentage of light, deep, and REM sleep can vary depending on age, health status, and other factors. However, here is a general breakdown of the recommended percentages for each stage of sleep:

• Light Sleep (NREM stages 1 and 2): 50-60% of your total sleep time.
• Deep Sleep (NREM stage 3): 13-25% of your total sleep time.
• REM Sleep: 20-25% of your total sleep time.

It's important to note that these percentages are just averages, and individual sleep needs may vary. Additionally, the amount of sleep you need and the percentage of each stage of sleep you experience can change throughout your lifetime.

How to get more deep sleep

Sleep is divided into non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. As people fall asleep, they advance through three stages of NREM sleep, followed by a period of REM sleep. This cycle repeats four to six times each night.

Deep sleep, or stage 3 NREM sleep, is a crucial stage of the sleep cycle that promotes physical and mental restoration. During this stage, the body repairs and regenerates, and the immune system is boosted. Most adults need around 1.5 to 2 hours of deep sleep per night, which equates to about 10 to 25% of total sleep time.

• Stick to a consistent sleep schedule: Try to go to bed and wake up at the same time every day, even on weekends. This helps to regulate your body's circadian rhythm and makes it easier to fall asleep and get the deep sleep you need.
• Manage stress and anxiety: Stress and anxiety can interfere with your sleep. Try relaxation techniques such as deep breathing, yoga, meditation, or progressive muscle relaxation. These practices can help calm your mind and prepare your body for deep sleep.
• Avoid caffeine and alcohol: Caffeine and alcohol can disrupt your sleep quality and reduce the amount of deep sleep you get. Avoid consuming these substances in the evening or close to bedtime to improve your sleep.
• Create a comfortable sleeping environment: Ensure your bedroom is dark, quiet, and cool. Consider using earplugs, an eye mask, or a white noise machine if you are disturbed by noise or light. A comfortable bed and pillows are also essential for getting a good night's sleep.
• Establish a bedtime routine: Consistency is key. Establish a relaxing bedtime routine to signal to your body that it's time to unwind and prepare for sleep. This could include reading, meditation, or taking a warm bath.
• Exercise regularly: Physical activity can help regulate your internal body clock and make it easier to fall asleep at night. However, avoid strenuous exercise close to bedtime, as it may increase your heart rate and make it harder to fall asleep.
• Eat a healthy diet: Consume nutrient-packed foods such as fruits, vegetables, and whole grains, which are high in fiber and can positively impact sleep. A healthy diet can contribute to more time spent in deep sleep.
• Avoid large meals, caffeine, nicotine, and alcohol close to bedtime: These substances can interfere with your sleep. Avoid consuming them within a few hours of bedtime to give your body time to process and relax before sleep.
• Practice relaxation exercises or meditation: If stress or anxiety keeps you awake, try relaxation techniques or meditation to calm your mind and prepare for sleep. This can include guided imagery or Sleep Stories, which are not just for children!
• Make your bedroom a sanctuary: Ensure your bedroom is cool, quiet, and dark. Consider using earplugs, an eye mask, or a white noise machine if needed. Invest in a high-quality mattress and pillows to enhance your comfort.

The importance of deep sleep

Deep sleep, also known as slow-wave sleep, is the third stage of non-rapid eye movement (NREM) sleep. During this stage, the body repairs and restores itself, and it is essential for maintaining health and well-being. While the amount of deep sleep needed varies by age, most adults should aim for 7-9 hours of sleep per night, with around 1.5-2 hours of deep sleep. Here are some key reasons why deep sleep is crucial:

Physical Restoration:

Deep sleep is the time when the body repairs and regenerates. Tissue growth and repair occur, and the immune system is strengthened. The body also releases growth hormones, which help build and repair muscles, bones, and tissues. This stage of sleep is especially important for athletes as it helps replenish energy stores.

Brain Health and Function:

Deep sleep is vital for brain health and cognitive function. It allows the brain to rest, recover, and replenish energy. It also plays a role in memory formation and retention. During this stage, the brain evaluates new memories and consolidates only the most relevant ones, making it easier to recall information.

Hormone Balance:

Deep sleep contributes to maintaining hormone balance. The pituitary gland releases growth hormones, and the body's natural rhythms, such as heart rate and breathing, are regulated.

Overall Health and Well-being:

A good night's deep sleep can help reduce the frequency of sickness, promote weight maintenance, lower the risk of heart disease and type 2 diabetes, improve decision-making, and enhance brain health. It may also play a role in preventing conditions like dementia and Alzheimer's disease.

Emotional Well-being:

While not as emotionally charged as REM sleep, deep sleep still plays a role in emotion regulation. A lack of deep sleep can lead to irritability and may exacerbate symptoms of depression and anxiety.

Learning and Memory:

Deep sleep is important for learning and memory consolidation. It helps the brain prepare for taking on new information and adapting to new environments. A lack of deep sleep can cause learning difficulties and impair memory formation.

In summary, deep sleep is a crucial stage of the sleep cycle, offering a range of physical and mental health benefits. It allows the body and brain to restore and prepare for the next day, contributing to overall health and well-being.

Sleep disorders associated with deep sleep

Sleep is divided into five stages, four of which are non-rapid eye movement (NREM) sleep, and one of which is rapid eye movement (REM) sleep. During the deepest NREM sleep, the body relaxes fully and repairs itself, while REM sleep is when we tend to dream.

Deep sleep is essential for health and well-being. Most adults need around 1.5 to 2 hours of deep sleep per night, which is about 25% of the total sleep. However, as people age, they need less deep sleep and spend more time in the lighter stages of sleep.

• Insomnia: Insomnia is characterised by frequent difficulty falling or staying asleep. It can lead to sleep deprivation, causing impaired concentration and memory, diminished reaction time, increased errors and poor performance at work. It can also cause increased levels of impatience, irritability, depression, and anxiety. Insomnia may be caused by psychological, medical, environmental, or lifestyle-related factors, such as caffeine consumption.
• Obstructive Sleep Apnea: Obstructive sleep apnea occurs when tissues in the mouth and throat relax, blocking the upper airway. It can cause people to snore heavily and wake up choking or gasping for air. It can also lead to daytime sleepiness, fatigue, morning headaches, and dry mouth. Obstructive sleep apnea is more common in overweight men.
• Restless Legs Syndrome (RLS): RLS causes an irresistible urge to move the legs, usually during times of rest or inactivity. It can be linked to iron deficiency, kidney failure, Parkinson's disease, diabetes, rheumatoid arthritis, or pregnancy. RLS can lead to sleep deprivation, causing impaired concentration and memory, diminished reaction time, and poor performance at work.
• Narcolepsy: Narcolepsy is a neurological disorder caused by a lack of hypocretin in the brain, which helps keep the brain awake and active. People with narcolepsy experience excessive daytime sleepiness and uncontrollable episodes of falling asleep during the day. They may also experience cataplexy (a sudden loss of muscle tone), hallucinations, and sleep paralysis.
• Shift Work Sleep Disorder: This disorder develops in people who work late nights or early mornings. Sleeping during the day and working at night can disrupt the body's natural circadian rhythms, leading to excessive tiredness at work and difficulty getting enough sleep.
• Delayed Sleep Phase Syndrome: People with this disorder fall asleep at least two hours after their desired bedtime and have difficulty waking up in time for school or work.
• Parasomnias: Parasomnias are a group of unusual sleep behaviours that can occur during sleep or while falling asleep. They include sleepwalking, bedwetting, night terrors, and exploding head syndrome. Parasomnias are most common in children but can also affect adults.
• Sleep Bruxism: Sleep bruxism is the grinding or clenching of teeth during sleep, which can lead to jaw disorders, headaches, and teeth damage.

What happens when you don't get enough deep sleep

Deep sleep, also known as slow-wave sleep, is an essential phase of the sleep cycle. It is during this stage that the body and mind engage in a deep restorative process. During deep sleep, the body carries out physical repair, immune system strengthening, memory consolidation, and the brain cleanses itself of metabolic wastes accumulated during the day.

Deep sleep is vital for your overall health and well-being. Here are some of the consequences of not getting enough deep sleep:

Physical Restoration

Deep sleep allows your body to repair and rejuvenate. It is a time for muscle and tissue recovery, making it crucial for physical health and growth. A lack of deep sleep can lead to slower recovery from injuries and illnesses, and can make chronic illnesses worse.

Immune Function

Deep sleep strengthens your immune system, helping you fight off infections and illnesses more effectively. Not getting enough deep sleep may result in a higher susceptibility to infections and a slower recovery from illness.

Memory Consolidation

During deep sleep, your brain processes and organizes information, transferring it from short-term to long-term memory. Insufficient deep sleep may lead to difficulty in making new memories or retaining information.

Cognitive Function

Deep sleep is associated with improved cognitive function, including problem-solving, creativity, and decision-making. A lack of deep sleep can result in lower cognitive functioning, making it difficult to focus and learn.

Emotional Regulation

Deep sleep contributes to emotional stability by regulating mood and reducing feelings of anxiety and stress. Not getting enough deep sleep can lead to irritability, anger, and even exacerbate symptoms of depression and anxiety.

Hormone Regulation

Deep sleep plays a role in regulating essential hormones such as cortisol and insulin, which are crucial for stress management and blood sugar balance. A lack of deep sleep can disrupt this regulation, affecting various bodily functions.

Heart Health

Deep sleep reduces blood pressure and heart rate, allowing your cardiovascular system to rest and recover. Not getting enough deep sleep can increase the risk of heart disease and other chronic illnesses.

To improve the quality of your sleep and ensure you get enough deep sleep, it is recommended to maintain a consistent sleep schedule, optimize your sleep environment, limit screen time before bed, engage in regular exercise, and practice relaxation techniques.

Frequently asked questions