Deep Sleep: Definition and Recommendations

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Deep sleep is a stage of rest defined by ultra-low brain activity. Deep sleep is known as slow-wave sleep because the brain waves are very slow during this time. The heart rate, breathing, and eye movements are slowest in deep sleep. Deep sleep occurs during the third stage of the sleep cycle. There are four sleep cycle stages, and they are divided into two categories, Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM).

The first three stages are NREM, and the fourth stage is REM. Deep sleep is Stage 3 of NREM sleep. Deep sleep is important because it is restorative. This stage supports physical growth, immune function, memory consolidation, and the hormones that control stress, appetite, and blood glucose levels. Not getting enough deep sleep can deter your body’s ability to regulate these functions, which could cause short-term and long-term health complications.

Tips to increase deep sleep include practicing good sleep habits, keeping a consistent schedule, having a comfortable bedroom and mattress, and addressing sleep disorders or other health issues. Some examples of good sleep habits include avoiding electronics before bed, cutting back on caffeine and alcohol, not eating late at night, and managing stress.

A consistent sleep schedule helps set your internal clock, which can foster better rest. Experts say the ideal space for sleeping is dark, quiet, and cool, and your bedroom should match these important qualities. A comfortable mattress can help you rest easier and achieve more deep sleep. Addressing sleep disorders and other underlying health issues that keep you up is necessary for a good night’s rest.

What Does Deep Sleep Mean?

Deep sleep means that a person is in a stage of rest where it is hard to wake them. The reason for this is that their brain waves are very slow during this time. The heart rate, breathing, and eye movements are at their slowest. Deep sleep happens in the third stage of the sleep cycle. Deep sleep is important because it is a restorative period.

Deep sleep fosters physical growth, immune function, memory consolidation, and the hormones that control stress, appetite, and blood glucose levels. Deep sleep is beneficial for managing stress, learning, preventing diabetes and obesity, physical energy, and strengthening your immune system.

Illustration of a Parents and Baby Sleeping in the Same Room

What Is the Stage of Deep Sleep?

The stage of deep sleep is the third in the sleep cycle. There are four stages of sleep. These stages are classified into two categories, NREM and REM. The first three stages are NREM, and the fourth stage is REM.

Deep sleep is Stage 3 of NREM sleep. The brain waves are extremely slow in deep sleep, so this stage is called slow-wave sleep. The person’s heart rate, breathing, and eye movements slow down to their lowest points. The slow brain waves mean that it is very hard to wake up someone in a deep sleep. If you awaken at this stage, you are likely to feel groggy.

How Much Deep Sleep Should You Get?

Healthy adults should get around 13-26 percent of their total sleep time in deep sleep. This amount equates to roughly 1-2 hours of deep sleep for every 8 hours of rest. Experts recommend that healthy adults sleep for 7-9 hours every night, with 8 being the average. The amount of deep sleep you get decreases with age.

A study titled Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem says that time in deep sleep declines by 2 percent every decade. Children and teens need more deep sleep than adults because it supports physical and cognitive growth. Young people experience abundant growth during this time and need the benefits of restorative sleep.

What are the Benefits of Getting enough Deep Sleep?

The benefits of getting enough deep sleep include lower stress levels, improved memory and learning skills, preventing diabetes and obesity, more physical energy, and a stronger immune system. We list these benefits of sleep in detail below.

  1. Lower Stress Levels: Deep sleep is beneficial for managing stress. Studies have shown that not sleeping enough can increase cortisol levels. Cortisol is the body’s stress hormone. Chronic stress is linked to mental and physical complications such as depression, anxiety, hypertension, heart attack, or stroke.

  2. Improved Memory and Learning Skills: Getting adequate deep sleep is good for your memory and learning skills. Sleep fosters memory consolidation, which is crucial for learning and retaining new information. Deep sleep is important for people of all ages, including students and workers.

  3. Helps Prevent Diabetes and Obesity: Deep sleep helps prevent diabetes and obesity. Two things can happen when you get good rest. First, the lack of sleep causes ghrelin hormone levels to increase, increasing your appetite. Second, too little rest can elevate blood glucose levels in the body. If this happens often, it may affect the body’s natural insulin resistance, resulting in diabetes.

  4. More Physical Energy: Deep sleep can increase your daytime energy. This sleep stage is highly restorative for the body, fostering tissue growth and repair. When you allow the body enough time to recharge itself, you should have more energy the following day. Increased energy means you are more likely to lead an active lifestyle.

  5. Stronger Immune System: Getting enough deep sleep helps maintain a strong immune system because this stage boosts immune function. The Mayo Clinic reports that important antibodies that fight off infections are reduced when sleep-deprived, leaving you more susceptible to illness.
Illustration of a Lady Enjoying in a Sunny Day

What Are the Harms of not Getting Enough Deep Sleep?

The harms of not getting enough deep sleep include increased stress, poor memory and learning capabilities, an increased risk for diabetes and obesity, less physical energy, and a weakened immune system. We list these harms in detail below.

  1. Increased Stress: Increased stress is one of the harms of not getting enough sleep. Research reveals that insufficient rest elevates cortisol levels, the body’s primary stress hormone. Frequent stress is tied to mental and physical issues, including depression, anxiety, hypertension, heart attack, or stroke.

  2. Poor Memory and Learning Capabilities: Insufficient deep sleep can lead to poor memory and learning capabilities. Sleep promotes memory consolidation, an essential part of learning and retaining new information. People of all ages, including students and employees, need good learning and memory abilities to succeed.

  3. Higher Risk for Diabetes and Obesity: Not enough deep sleep creates a higher risk for diabetes and obesity. Poor sleep causes ghrelin levels to skyrocket. Ghrelin is an appetite hormone, and this jump can cause you to feel hungrier than usual. Insufficient rest also increases the body’s blood glucose levels. If this frequently happens, the body’s insulin resistance is impacted, potentially leading to diabetes.

  4. Less Physical Energy: Less physical energy is a harmful side effect of not getting enough sleep. The deep sleep stage allows the body to restore itself. When it’s not able to, you will feel more lethargic. Reduced energy means you will be less inclined to lead an active lifestyle.

  5. Weakened Immune System: Reduced deep sleep can weaken your immune system. The number of antibodies that help prevent infections from entering the body decreases when you are sleep-deprived, increasing your chances of becoming sick.
Illustration of a Lady Looking at Dark Circles over Her Eyes in the Mirror

What is the Best Time to Get Deep Sleep?

The best time to get deep sleep is overnight when it is dark outside. Light regulates the body’s circadian rhythm, a series of physiological changes that follow a 24-hour cycle. When it’s dark outside, the body prepares itself for sleep.

One way it does this is by releasing more melatonin, a hormone that promotes sleep. Melatonin amounts decrease when the sun’s out. Trying to sleep when it’s light out goes against the body’s natural rhythm, which is why many shift workers are prone to sleep deprivation. If your work schedule does not allow you to sleep on a consistent nighttime schedule, you should make your bedroom as dark as possible. Blackout curtains can help block out light that interferes with sleep.

How to Increase the Amount of Deep Sleep

Ways to increase the amount of deep sleep you get include practicing good sleep habits, keeping a consistent schedule, having a comfortable bedroom and mattress, and treating sleep disorders or other health issues. We list these sleep tips in detail below.

  1. Practice Good Sleep Habits: Practicing good sleep habits should increase deep sleep. Good habits include cutting off electronics before bed, avoiding caffeine and alcohol, not eating big meals late at night, and managing stress. Devices like cell phones and computers emit a blue light that suppresses melatonin production, causing alertness. Caffeine can make it harder for you to feel tired at night, while alcohol has been shown to cause more fragmented sleep patterns. Eating too much food late at night can be uncomfortable, and certain foods may trigger heartburn. Not managing stress can affect your ability to relax and fall asleep.

  2. Consistent Schedule: Keeping a consistent sleep schedule should improve your deep sleep because it helps set your internal clock. You need to establish a bedtime and wake-up that work for you and stick to those times every day of the week, including weekends.

  3. Comfortable Bedroom and Mattress: Ensuring your bedroom is comfortable will improve your rest. Experts say it’s best to sleep in a cool, dark, and quiet room. If your room does not meet these standards, you should find ways to improve it, such as using blackout curtains, earbuds, and opening a window. The right mattress will help you sleep soundly. If you notice your bed isn’t as comfortable as you’d like, consider investing in a new one that’s a better fit for your needs and preferences.

  4. Treating Sleep Disorders and Other Health Issues: Treating sleep disorders and other health issues because these can interfere with your sleep quality. Some disorders may be managed through healthy lifestyle habits. If you continue to experience symptoms, speak with your doctor or a sleep specialist, who can help diagnose your condition and set up an appropriate treatment plan.
Illustration of a Man Flipping His Mattress

Can Listening to Music help you get Good Deep Sleep?

Yes, listening to music can help you get good deep sleep. Music and sleep quality are often connected because melodies and lullabies are popular for helping kids sleep better. Research suggests music may help adults sleep soundly too. A 2003 study titled The use of music to promote sleep in older women studied the effects of music on a group of women over the age of 70. They found that music decreased the time it took to fall asleep and the number of times they woke up during the night.

Reducing the number of times someone awakes overnight increases a person’s chance of getting more deep sleep. This news is helpful for older people since they experience a decline in deep sleep. The best music for sleep is slow and calming. A study titled Releasing stress through the power of music found that the ideal genres, instruments, and sounds include Native American, Celtic, Indian-stringed instruments, drums, flutes, nature, thunder, and rain.

Is Meditation Good for Deep Sleep?

Yes, meditation is good for deep sleep. Many people have difficulty sleeping soundly due to stress. The mediation effect on sleep is beneficial because it provides a way to relieve stress. Meditation is a practice where an individual focuses on one particular thing, such as an image or object. The goal of meditation is to keep out thoughts that cause you to feel overwhelmed. Meditation can be done any time of the day, but if you want to improve your sleep, schedule a time to meditate shortly before going to bed.

There are tips you can follow if you’re new to meditating. First, create a space to meditate that feels calming. Second, take some deep breaths as you try to focus and relax your mind. Try using a meditation app such as Headspace or Calm if you experience roadblocks.

Illustration of a Woman Meditating Before Bed

What Items Can Be Used for Getting Quality Deep Sleep?

Items you can use to get quality deep sleep include blackout curtains, eye masks, earbuds, a fan, a weighted blanket, essential oils, and CBD oil.  We have listed the products for better sleep below.

  1. Blackout Curtains: Blackout curtains can foster deep sleep by blocking out light. Exposure to light can make it harder to sleep soundly. Blackout curtains may be especially helpful for shift workers or those who live in cities with a lot of artificial light outside.

  2. Eye Masks: Eye masks can help eliminate distracting light and are an economical alternative to blackout curtains. Many eye masks are available for 20 dollars or less. If you plan to use one, be sure that the fit and material are comfortable.

  3. Earbuds: Earbuds can improve deep sleep by blocking out noise. Loud neighbors, roommates, and a significant other may cause you to wake up during the night. Wearing earbuds can provide a barrier that could make you less likely to hear them while you’re in bed.

  4. Fans: Fans are a great way to sleep better because they keep you cool. If your room is too warm, this could cause you to awaken during the night. Keeping a fan on will help prevent you from overheating.

  5. Weighted Blanket: Weighted blankets are a well-known method for improving sleep for those with anxiety. The weight of the blanket is designed to help provide emotional comfort for better rest.

  6. Essential Oils: Essential oils are a great way to foster relaxation and better shut-eye. Many people choose to use a diffuser with essential oils to give their room a calming scent. One of the most popular scents for good sleep is lavender.

  7. CBD Oil: CBD oil may help promote more deep sleep. CBD comes from marijuana, but it does not contain tetrahydrocannabinol (THC), the psychoactive ingredient in marijuana that causes people to feel high. Multiple studies have shown sleep improvements from using CBD oil. The common way to use CBD oil is to place several drops under the tongue and wait 30-60 seconds before swallowing.
Illustration of a Bottles of Essential Oils for Sleep

Can a Mattress Affect Deep Sleep Quality?

Yes, a mattress can affect deep sleep quality. A bed that doesn’t provide pressure relief, support, and other helpful features could lead to more restless nights. The right mattress should be a good match for your specific needs and preferences. Mattress quality for sleep is based on multiple factors such as your sleep position, personal preferences, how much you weigh, health needs, and whether you sleep with a partner.

What Is the Difference Between Deep Sleep and REM Sleep?

The difference between deep sleep and REM sleep is that they are two different stages of sleep. Deep sleep is the third stage of the sleep cycle and the final stage of the NREM phase. REM sleep is the fourth sleep cycle stage and the only stage in REM rest.

Deep sleep exhibits the lowest brain activity, and REM sleep has the highest amount. Deep sleep is characterized by slow brain waves, heart rate, breathing, and eye movements. REM sleep is characterized by quick eye movements and heightened brain activity. One of the similarities of these two stages is that it is harder to wake up in deep or REM sleep.

Waking up during either of these stages can leave you feeling groggy and unrefreshed. Sleep experts recommend that people do not wake up during these stages in order to feel well-rested in the morning.

Illustration of a Person Dreaming

What Is the Difference Between Deep Sleep and Light Sleep?

The difference between deep sleep and light sleep is that it is harder to wake up during deep sleep than light sleep. Deep sleep is the third stage of the sleep cycle. The first two stages of the cycle are a light sleep. You begin to doze off during light sleep, and your body and brain activity slow down until they reach their lowest point in deep sleep.

One similarity that deep and light sleep share is that they are both in the NREM phase of the sleep cycle. Sleep health experts say it’s better to wake up during light sleep because you're more likely to feel refreshed.

Content Writer

Jill Zwarensteyn is a content writer for Sleep Advisor and is enthusiastic about providing helpful and engaging information on all things sleep and wellness.

Based in Los Angeles, she is an experienced writer and journalist who enjoys spending her free time at the beach, hiking, reading, or exploring new places around town.

She’s also an avid traveler who has a personal goal of being able to successfully sleep on an airplane someday.

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