How Much Deep Sleep Do You Need? Average Hours Based On Age + Sex

We picked the brains of three sleep experts for their top tips on how to improve your sleep.

Deep sleep often gets lauded as the most important phase of sleep by fitness trackers that give you a “sleep score.”

According to experts, 25% of your sleep duration should be in the deep sleep phase. Therefore, if you sleep a total of eight hours at night, you would ideally have two hours of deep sleep per night.

In this sleep guide, we spoke to three sleep experts to get their insight into how deep sleep works, average deep sleep per night, and ultimately answer your question: “How much deep sleep do you need?”

Let’s jump in!

A person in deep sleep.

What Are the Stages of Sleep?

Dan Ford, a Sleep Psychologist and Founder of The Better Sleep Clinic says there are four different stages of sleep, broadly divided into non-rem sleep (non-rapid eye movement or NREM sleep) stages 1, 2, and 3, and stage 4 rapid eye movement sleep (REM). 

“Each stage is characterized by different brainwave patterns on an EEG,” explains Ford.

“As you fall asleep during the night, you will progress through stages 1, 2, and 3 in order, before rapidly rising back through the stages and into REM sleep. A full cycle of these stages lasts around 90 to 110 minutes.”

What Is Deep Sleep, and Why Is Deep Sleep Important?

Bianca Grover, an Exercise Physiologist, Medical Exercise Specialist, Health Coach, and Owner of Bianca Grover Fitness, explains that the deep sleep phase of the sleep cycle also called the N3 sleep phase, was previously broken into two separate deep sleep stages but the scientific community agreed that was not necessary. 

A person sleeping.

Therefore, the deep sleep phase is now consolidated into the single N3 deep sleep cycle phase.

“As the name suggests, [deep sleep] is the furthest away from an awake state we get to in the night,” shares Grover. “Deep sleep is associated with strengthening muscle, bones, tissue, and immune function.”1Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., LaMantia, A.-S., McNamara, J. O., & S Mark Williams. (2001). Stages of Sleep. Nih.gov; Sinauer Associates. https://www.ncbi.nlm.nih.gov/books/NBK10996/

Susan Miller, a Certified Sleep Technician, Registered Polysomnographic Technologist™ (RPSGT), and Founder of Sleep Mattress HQ, says that during deep sleep, also known as slow-wave sleep, the body undergoes physical restoration.

This is why getting enough deep sleep at night is imperative for recovery from workouts, the stress of daily life, and preventing illnesses and injuries.

“Deep sleep is marked by a slowed heart rate, reduced blood pressure, and increased blood flow to muscles. Growth hormones are released, supporting tissue repair and muscle development,” shares Miller.

“Deep sleep is vital for physical recovery, immune function, and overall well-being.”

A person sleeping with a sleep mask on.

How Much Deep Sleep Do You Need Per Night?

Grover suggests that much like the amount of time spent in REM sleep per night, you should spend about 25% of your hours of sleep in the deep sleep phase.

Therefore, if you sleep a total of eight hours at night, you would ideally have two hours of deep sleep per night.

Remember, you go through multiple sleep cycles per night, so you will hit the deep sleep phase several times and then come out of deep sleep into REM sleep and light sleep before cycling back down into the N3 deep sleep stage.

According to Grover, “The deep sleep cycle portion lands between 20-40 minutes every time you hit it.”

However, unlike light sleep, it takes time to get into deep sleep; you have to work through the light sleep phases before you hit deep sleep.

Therefore, if you wake up frequently through the night, you will be less likely to have enough time between each waking to get into a deep sleep and then spend any inappreciable amount of time in a deep sleep before you are woken back up.

That said, because deep sleep is inherently “deeper“ than light sleep, you are less prone to be roused from your sleep by small sounds or other sensory disruptions when you are in a deep sleep vs. the light sleep stages.

A person asleep in bed.

Which is Better REM or Deep Sleep?

Miller explains the physiological differences between the REM stage and deep sleep stage: 

“REM (Rapid Eye Movement) sleep is characterized by increased brain activity. It’s when vivid dreaming occurs. REM supports cognitive functions, memory consolidation, and emotional processing,” she notes.

“The brain experiences heightened activity similar to wakefulness, promoting learning and creativity.”

She continues, “In contrast, deep sleep is a sleep stage where the body experiences profound physical restoration,” says Miller. “It’s crucial for muscle repair, immune function, and overall health. During deep sleep, the brain emits slow delta waves.”

Miller explains that while we tend to revere deep sleep as the best sleep or make black-and-white statements like it is better to get more deep sleep vs REM sleep, neither REM nor deep sleep is inherently “better” than the other.

Rather, deep sleep and REM sleep phases both serve different functions and provide crucial benefits to the mind and body.

“Deep sleep is crucial for physical restoration and growth hormone release, while REM supports cognitive functions, memory consolidation, and emotional processing,” explains Miller. “Both are vital for overall health.”

Grover agrees that deep sleep—or any phase of sleep for that matter—isn’t inherently better or more important than another phase.

“Prioritizing or stressing over a particular phase of sleep may not be the best approach. All phases of sleep play an important part, and everyone’s body is different,” warns Grover.

A person asleep in bed.

Does the Amount of Deep Sleep Per Night Change With Age or Sex?

Miller says that the normal amount of deep sleep per night tends to change with older adults and can also be influenced by sex. 

“Generally, infants and young children experience more deep sleep, constituting a significant portion of their sleep cycles. As individuals age, the percentage of deep sleep decreases,” notes Miller.

“In terms of sex, there can be variations. Women often show a slightly higher percentage of deep sleep compared to men, although these differences are subtle. Factors such as hormonal fluctuations and life stages, like pregnancy, can influence sleep patterns in women.”

How To Get More Deep Sleep?

Grover says that the best way to increase your average deep sleep per night is to try to improve your overall sleep quality.

She provides several tips for how to get more deep sleep, improve overall sleep quality and quantity and cater to your sleep needs:

A person asleep in bed.
  • Avoid alcohol and caffeine, especially before bed. Grover explains that although alcohol may make you feel more relaxed, it actually disturbs your body’s normal sleep cycles.
  • Create a sleep schedule. Creating a bedtime routine that you practice consistently will help let your body know when it is time to start winding down for the day and when it should get ready to gear up in the morning. These sleep habits can improve your sleep efficiency and help you feel more ready to go when you wake up.
  • Go outside and expose yourself to the sun. Exposure to sunlight, especially closer to the beginning and end of our day, provides a similar effect as a sleep schedule—clueing the body that it is time for sleep.
  • Exercise regularly. Grover says that consistent exercise has been shown to reduce the amount of time it takes to fall asleep and has shown signs of improving overall quality sleep.2Alnawwar, M. A., Alraddadi, M. I., Algethmi, R. A., Salem, G. A., Salem, M. A., Alharbi, A. A., Alnawwar, M. A., Alraddadi, M. I., Algethmi, R. A., Salem, G. A., Salem, M. A., & Alharbi, A. A. (2023). The Effect of Physical Activity on Sleep Quality and Sleep Disorder: A Systematic Review. Cureus15(8). https://doi.org/10.7759/cureus.43595
  • Turn your phone off or use a blue light filter before bed. “Just like your muscles and body need to begin relaxing, so does your mind,” advises Grover. “The light from your phone can actually trick your brain into thinking it should stay up and be active.”
A person asleep in bed.

I personally struggle with getting enough total sleep time, according to my Oura Ring sleep tracking. Therefore, I’m always keen to try various relaxation things and sleep stuff to improve my sleep quality and beat sleep deprivation and insomnia.

My latest obsession is the heatable (and huggable!) Warmies. They are not only soft, comforting, and adorable to hug, but the aromatherapy helps soothe and relax my body and mind.

If you can’t get yourself to hug a stuffed animal, the Warmies Slippers are also a great way to ease tension (and sore feet!) to relax before bed.

I also suggest getting a good comforter or duvet to help regulate your body temperature so you don’t get too hot.

My recommendation for the best down comforter is the Beautyrest Hungarian White Goose Down Comforter. 

So far, these are my new favorite sleep products. They are helping me fall asleep faster! Give our tips a try to see if you can improve your sleep quality and get a good night’s sleep to be ready for the next day.

Interested to continue learning about sleep in general? Check out:

References

  • 1
    Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., LaMantia, A.-S., McNamara, J. O., & S Mark Williams. (2001). Stages of Sleep. Nih.gov; Sinauer Associates. https://www.ncbi.nlm.nih.gov/books/NBK10996/
  • 2
    Alnawwar, M. A., Alraddadi, M. I., Algethmi, R. A., Salem, G. A., Salem, M. A., Alharbi, A. A., Alnawwar, M. A., Alraddadi, M. I., Algethmi, R. A., Salem, G. A., Salem, M. A., & Alharbi, A. A. (2023). The Effect of Physical Activity on Sleep Quality and Sleep Disorder: A Systematic Review. Cureus15(8). https://doi.org/10.7759/cureus.43595
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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