How much deep sleep do you need and are you getting enough? Here's how to tell

Many things go into getting a good night’s rest — including getting enough deep sleep. While “deep” and “quality” sleep might sound interchangeable, deep sleep is actually one of the four sleep stages, and it’s arguably the most important stage of non-REM (NREM) sleep.

Deep sleep is famed for being the most restorative stage of stage and where important repair and recovery processes take place. But now that you know how important it is, are you aware of how much you actually require?

We asked Roger Washington, MD, FAAFP, a family medicine physician, sleep therapist, and the founder of the Sleep To Live Well Foundation, to help us unpack the basics of deep sleep. Ahead, you’ll discover the distinct role it plays and how much deep sleep you need each night, depending on your age.

What is deep sleep?

Also known as slow wave sleep or N3 sleep, deep sleep is the third and final non-REM sleep stage before transitioning to rapid-eye movement (REM) sleep. In this phase of sleep, “the brain disengages from external sensing, learning, and problem-solving and shifts fully toward internal repair and recalibration,” says Dr. Washington.

A lot of important work for your physical and mental health occurs during this sleep stage. In this stage, Dr. Washington says that:

• Growth hormone secretion peaks
• Immune signaling is recalibrated
• Inflammatory tone is reduced
• Muscles, connective tissue, and metabolic systems are repaired
• Cellular electrical and sensory thresholds are reset, which improve clarity, emotional stability, and stress tolerance the following day

How much deep sleep do you need?

The amount of deep sleep we need changes by age, as well as other personalized factors like health conditions. Dr. Washington advises not getting tripped up over the precise numbers, though.

“These figures support what I’ve observed in my practice: healthy sleepers tend to fall within these ranges when their total sleep time and timing are adequate,” he says. Nonetheless, “they are not strict targets for each night.”

With that in mind, here’s a rundown of the average amount of sleep you need according to your age group:

Babies (4 months to 2 years)

According to Dr. Washington, typical deep sleep during this age range is 90 to 150 minutes per night.

“Babies spend a much larger share of sleep in deep sleep because growth hormone release, immune development, and neural wiring dominate physiology at this stage,” he says. “This elevated need persists through the first two years of life and then gradually declines as growth velocity slows.”

Children (3 to 12 years)

Dr. Washington says that toddlers and children in this age bracket typically require 60 to 120 minutes of deep sleep each night.

“Children continue to require substantial deep sleep to support physical growth, immune maturation, and brain development,” he says.

As long as children are able to get enough sleep time spent asleep — which is 10 to 13 hours (for children ages 3 to 5) and 9 to 12 hours (for children ages 6 to 12), per the American Academy of Sleep Medicine (AASM) — Dr. Washington says that deep sleep is usually abundant. However, he says that total deep sleep falls when bedtimes are delayed, even though the body still prioritizes it early in the night.

Teenagers (13 to 18 years)

According to Dr. Washington, teens get an average of 60 to 90 minutes per night.

“Adolescents need deep sleep to support hormonal regulation, musculoskeletal growth, and emotional development,” he says. “However, delayed circadian timing combined with early school schedules often shortens total sleep, reducing the absolute amount of deep sleep obtained.”

With packed schedules, teens may find it challenging to get the 8 to 10 hours of total sleep recommended by the AASM.

Young adults (18 to 25 years)

Perhaps surprisingly, adults up to the age of 25 often need the same amount of deep sleep as teenagers, which again is 60 to 90 minutes per night.

Curious as to why this is? “Although legally considered adults, brain maturation — particularly in males — continues into the mid-20s,” Dr. Washington explains. “Sleep patterns during this period often resemble late adolescence, and deep sleep commonly remains toward the upper end of the adult range.”

Adults (26 to 64 years)

Per Dr. Washington, adults aged 26 through 64 years old require less deep sleep than teens and young adults, with average ranges clocking in at 45 to 90 minutes per night.

But just because most adults require less deep sleep than younger demographics doesn’t mean that it’s any less important to get. “In adulthood, deep sleep supports physical repair, immune function, metabolic regulation, and emotional stability,” says Dr. Washington.

And while you might get less, “the biological need for deep sleep does not disappear.” Rather, adults tend to “lose the conditions that allow it to extend.”

He adds that the amount of deep sleep you get varies widely on factors like stress, mental load, sleep timing, and sleep debt (i.e., getting less sleep than you actually need — which, for most adults, is 7 to 9 hours per night).

Older adults (65+)

Older adults get the least amount of deep sleep across all age groups. Per Dr. Washington, those 65 and older log an average of 30 to 60 minutes of deep sleep each night.

“Older adults tend to experience lighter, more fragmented sleep, which reduces deep-sleep time,” he says. “This reflects changes in sleep regulation rather than a reduced biological need.”

While older adults may struggle to get the same quality shuteye they once did in their earlier years, Dr. Washington says that deeper sleep can improve with consistent timing and sufficient sleep opportunity.

Signs you’re not getting enough deep sleep

According to Dr. Washington, there are many signs that indicate you’re not getting enough deep, restorative sleep. These include:

• Needing an alarm clock to wake up
• Dependence on caffeine or stimulants
• Irritability or emotional volatility
• Carbohydrate and sugar cravings
• Afternoon brain fog
• Feeling tired but wired at night

“These patterns are often misattributed to stress, personality, or aging,” says Dr. Washington, “but more often, they reflect sleep debt and circadian misalignment.”

In a perfect world, we’d all get enough deep sleep (and total sleep) to allow us to feel and function our best. However, Dr. Washington advises against trying to “hack” your way to get more deep sleep — and especially against losing sleep over your numbers if you track your ZZZ’s with wearables. “Deep sleep is not generated by effort,” he says. “It lengthens naturally as alignment improves.”

With this in mind, he instead encourages better rest and alignment by:

• Respecting circadian timing with light exposure, food timing, and physical activity
• Winding down the day free from a heavy mental load
• Addressing unresolved stress or trauma that keeps you vigilant at night

“When alignment improves, deep sleep extends naturally,” Dr. Washington concludes.

If you try out these methods and nothing still works, it could be time to discuss your options — be it a sleep study, therapy, or medical intervention — with a health professional.

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