How to Resolve a Lack of Deep Sleep

Almost everyone can benefit from more sleep. Deep sleep is even more important. In fact, a lack of deep sleep can impact your health.

What exactly is “deep” sleep? How do you know if you’re getting enough of it? And what can be done if you’re not?

This article discusses what deep sleep is and what its health benefits are. It also looks at the causes and solutions for decreased deep sleep, and helps you decide if you are getting enough deep sleep.

causes of decreased deep sleep

Verywell / Brianna Gilmartin

What Is Deep Sleep?

Deep sleep is also called slow-wave sleep. It gets this name from the slow brain waves, called delta waves, that the brain produces during this time.

Slow-wave sleep is the deepest sleep stage. It is also called NREM Stage 3 sleep. This stage happens more in the first third of the night. It is very hard to wake someone from deep sleep.

The Stages of Sleep Were Revised in 2007

Until recently, sleep was divided into five stages. Deep sleep was called stage 4. In 2007, the American Academy of Sleep Medicine (AASM) changed this. Today, sleep is divided into four stages:

  • NREM Stage 1
  • NREM Stage 2
  • NREM Stage 3
  • REM Sleep

How Much Deep Sleep Do You Need?

People of different ages spend different amounts of time in deep sleep. Children spend more time in deep sleep than adults. Generally speaking, school-aged kids and teens need to spend 20-25% of their sleep time in deep sleep. Adults should spend about 16-20% of their sleep time in deep sleep. 

Studies have found people spend less time in deep sleep as they get older. Men, though, tend to have a much sharper decrease in deep sleep than women as they age.

Health Benefits of Deep Sleep

During deep sleep, the body releases growth hormone. This is a chemical that helps build and repair tissues.

Growth hormone is vital for normal growth in childhood, but it also plays a role in adult bodies. It helps build muscle after exercise and limit the effects of normal wear and tear on the body. The increased blood flow to the muscles that happens during deep sleep helps these processes.

Deep sleep may also play a role in clearing waste from the brain, such as a protein called beta-amyloid, which is found in abnormal amounts in the brains of Alzheimer's patients. Removing this waste helps your brain process and store memories.

Deep sleep also helps your immune system function better, and puts energy back into your cells.

Risks Associated With Lack of Deep Sleep

It is clear that lack of sleep is bad for your health. When you don't get enough deep sleep, you get poorer quality sleep overall. Impacts on your body and brain can include:

Pain

A lack of deep sleep can make chronic pain worse. This may show up in different ways. It may even lead to a diagnosis of fibromyalgia, which is characterized by pain, depression, and fatigue. When you get more deep sleep, you may feel less pain.

Impaired Growth

Children with untreated sleep disorders like sleep apnea will get less deep sleep. Reduced deep sleep interferes with the release of growth hormone. This may lead to slower-than-normal growth. Fortunately, children may catch up on growth once they receive treatment for their sleep disorder.

Dementia

Beta-amyloid plaques build up in the brain tissue of Alzheimer’s patients. A lack of deep sleep may interfere with the process of clearing these proteins. This could make the disease progress more quickly.

Immune Function and Chronic Diseases

A lack of deep sleep may also harm your immune system. You may get more common illnesses like colds or influenza (flu). Lack of deep sleep may also increase your risk of developing chronic diseases like heart disease or cancer.

Recap

Deep sleep is important for good health. During deep sleep, your body repairs itself and clears waste from your brain. When you don't get enough deep sleep, your immune system doesn't function as well. You may also be at greater risk for Alzheimer's disease and chronic diseases like cancer.

Are You Getting Enough Deep Sleep?

You can usually tell when you aren't getting enough deep sleep. You may have frequent arousals, or too many transitions from deep to light sleep. You may also wake up completely. When you get up in the morning, you might still feel tired. Throughout the day, you may be sleepy or fatigued.

Unfortunately, there is no easy, accurate way to measure sleep stages. This makes it hard to know for sure how much deep sleep you are getting each night.

The gold standard test for diagnosing sleep problems is the polysomnogram. This is a formal study done at a sleep center that measures: 

  • Electrical activity of the brain (including sleep stages), which is measured with an electroencephalogram (EEG)
  • Muscle activity
  • Eye movements
  • Breathing patterns
  • Oxygen levels
  • Heart rhythm, which is measured with an electrocardiogram (ECG or EKG)
  • Leg movements

There are some limitations to this test. It is disruptive to sleep, and it is not good for long-term monitoring. It is also expensive, and not available to everyone. The test is very good at measuring deep sleep. It can not provide detailed insight into the long-term quality of your sleep, though.

Wearable devices could help fill the void left by sleep center testing. Fitness trackers and similar devices are convenient and can be used over the long term. These devices use a few different measurements to track your sleep, including:

  • Movement
  • Heart rate
  • Oxygen levels (some devices)
  • EEG (some devices)

Wearable devices can give you an overview of your sleep patterns. Unfortunately, though, these measurements don't give you a very accurate picture of your deep sleep.

Over time, these devices may become more accurate, and will be more useful for understanding long-term sleep.

Recap

If you aren't getting enough deep sleep, you will probably wake feeling tired and have sleepiness during the day.

Unfortunately, it can be difficult to measure how much deep sleep you're getting. Getting a polysomnogram at a sleep center might be helpful. Wearable devices can also give you a good overview of your sleep. None of these things will give you a complete picture of your sleep, though.

What Causes Decreased Deep Sleep?

These factors may contribute to a lack of deep sleep.

Weakened Sleep Drive

Taking naps or spending too much time in bed can weaken your sleep drive. This means you could lose some of your ability to sleep normally, and you may get less deep sleep.

Sleep Disorders

Some sleep disorders can disturb deep sleep. People with sleep apnea will frequently stop breathing while asleep. People with periodic limb movements of sleep (PLMS) involuntarily move their legs while asleep. Both these disorders can cause you to wake up often.

Disruptions in sleep may reduce deep sleep. When these disorders are effectively treated, you may start getting more deep sleep again. Over time, the balance of your sleep stages will become normal again.

Substance Use and Withdrawal

Certain medications and other substances can reduce deep sleep. These include:

  • Caffeine
  • Benzodiazepines
  • Opioid medications

Caffeine is the stimulant found in coffee, tea, and many other beverages. Caffeine may reduce deep sleep. This effect can even happen hours after you consume it.

Benzodiazepines, the class of tranquilizer drugs that includes Valium (diazepam), may also reduce deep sleep. Opioid medications can have the same effect.

Some medications may increase deep sleep. These include:

  • Desyrel (trazodone)
  • Marijuana
  • Lithobid (lithium)

Trazodone is an older antidepressant that is often used as a sleep aid. This drug appears to interact with histamines, compounds released during allergic reactions. This seems to increase deep sleep.

Marijuana may also enhance slow-wave sleep. Lithium, a medication for bipolar disorder, may have a similar effect. These drugs are sometimes prescribed for sleep disorders.

Some sleep aids don't seem to impact deep sleep one way or another. These non-benzodiazepine sleep aids include:

  • Ambien, Zolpimist, Edluar (zolpidem)
  • Lunesta (eszopiclone)
  • Sonata (zaleplon)

Recap

Lack of deep sleep can have many different causes. Taking naps or spending too much time in bed can weaken your sleep drive. Sleep disorders like sleep apnea can cause you to wake up at night. Certain substances like caffeine can also have an effect on how much sleep you get. 

Strategies For Increasing Deep Sleep

We know that deep sleep is important to how you feel about your quality of sleep. We also know it can have an impact on your health and quality of life. Still, it is surprising how little we know about how to increase deep sleep. Fortunately, there are a few things you can try.

Boost Sleep Drive

Being are awake for long periods of time can enhance your "homeostatic sleep drive." In other words, the longer you stay awake, the more you want to sleep. When you finally do sleep, you may have an increase in deep sleep.

This is called sleep consolidation or sleep restriction, and it's an effective way to treat insomnia. Sleep restriction is used as part of a cognitive behavioral therapy for insomnia (CBTI) program. Sleep deprivation can lead to deeper periods of sleep.

Follow a Circadian Rhythm (Internal Clock)

Deep sleep follows a circadian pattern, also known as an internal clock. You get more deep sleep earlier in the night. When your sleep is irregular, that interferes with the timing of deep sleep. That can cause you to get less deep sleep.

Keeping a regular sleep and wake schedule can help. This includes weekends. It can also help to get some morning sunlight as soon as you wake up. Sunlight can work as a cue for your circadian system.

Change Behaviors and Environment

More research on the effects of behavior and the environment on deep sleep is needed. Exercise and daytime physical activity may help. Unfortunately, we're less certain about details like the timing of physical activity.

It may also help to take a warm bath or shower about 90 minutes before you go to bed. A cooler bedroom could also improve deep sleep. Light, noise, and warmer temperatures may have the opposite effect.

Devices that emit electrical patterns, vibrations, sounds, or light may help enhance deep sleep. There is also a headband on the market that claims to improve deep sleep by changing your brain waves, but its effectiveness is unproven.

Recap

There are a few things you can try to improve your deep sleep. Set a regular sleep schedule to follow every day, even weekends. Make sure your bedroom is cool and quiet and avoid using devices in bed. You can also try using a sleep device.

Summary

Deep sleep, also called NREM Stage 3 sleep, is the deepest stage of sleep. This sleep stage is important for repairing the body and clearing waste from the brain. Lack of deep sleep may harm your immune system, and can increase the risk for dementia and chronic diseases like cancer. 

Weakened sleep drive, sleep disorders, and substance abuse can lead to a decrease in deep sleep. You may be able to increase your deep sleep with a regular sleep schedule or a change in your sleeping environment. If not, a board-certified sleep medicine physician may be able to help. 

A Word From Verywell

If you are concerned about your deep sleep, start with what you can control. Adopt a regular sleep-wake schedule, including weekends. Create a sleep sanctuary. Make your bedroom a place for sleeping, and don't use electronics in bed.

Avoid naps and don't spend too much time trying to sleep. Most adults need seven to nine hours of sleep to feel rested, but older adults may only need seven to eight hours. Limit your intake of caffeine and avoid other substances that may reduce deep sleep.

If you think you may have a sleep disorder like sleep apnea or insomnia, consult a doctor. A board-certified sleep medicine physician can help you find answers.

These simple changes may help you get the deep sleep you need for well-being and your long-term health.

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Article Sources
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Additional Reading
  • Kryger M, Roth T, Dement W. Principles and Practice of Sleep Medicine, 6th edition. Elsevier; 2016.