How to Get More Deep Sleep: Why It Matters and Signs You’re Not Getting Enough

Last updated October 23, 2026

Short answer: To get more deep sleep, keep the same sleep and wake times every day, exercise most days (but not close to bedtime), avoid caffeine late in the day and alcohol before bed, and sleep in a cool, dark, quiet room. Deep sleep happens mostly in the first half of the night, so a regular, reasonable bedtime protects it. You cannot force deep sleep, but these habits give your body the best chance to reach it.

Key Takeaways

• Deep sleep is stage 3 of non-REM sleep, also called slow-wave sleep. It is the stage you need to feel refreshed in the morning.
• Most deep sleep happens in the first half of the night.
• Alcohol, a warm bedroom, late caffeine, light, noise, and short or irregular sleep can all reduce deep sleep.
• Deep sleep naturally decreases with age. This is a normal change.
• Only a sleep study can measure your sleep stages accurately. Sleep trackers give a rough estimate.

What Is Deep Sleep?

Deep sleep is stage 3 of non-REM sleep. It is also called slow-wave sleep, after the slow brain wave pattern that shows up in sleep studies. The National Institute of Neurological Disorders and Stroke (NINDS) describes it as the deep sleep you need to feel refreshed in the morning. During deep sleep:

• Your heartbeat and breathing slow to their lowest levels of the night
• Your muscles are relaxed
• Your brain waves become even slower
• It may be hard for someone to wake you

Where deep sleep fits in a night of sleep

Sleep is not one steady state. The National Heart, Lung, and Blood Institute (NHLBI) explains that you cycle through two phases: non-REM sleep and REM (rapid eye movement) sleep. A cycle starts over every 80 to 100 minutes, and there are usually four to six cycles a night. You may wake up briefly between cycles.

Stage	Type	What happens
Stage 1	Light non-REM	The changeover from being awake to sleep. It usually lasts several minutes.
Stage 2	Light non-REM	Heartbeat and breathing slow, and body temperature drops. You spend more time here than in any other stage.
Stage 3	Deep non-REM	Deep or slow-wave sleep. Heartbeat and breathing are at their lowest. You are hard to wake.
REM	REM	Brain activity is close to waking levels. Most dreaming happens here.

Deep sleep comes in longer periods during the first half of the night. REM periods get longer toward morning.

Deep sleep vs. REM sleep

	Deep sleep	REM sleep
When it happens	Mostly in the first half of the night	Mostly later in the night
Brain activity	Very slow brain waves	Close to waking levels
Heartbeat and breathing	Slowest of the night	Faster and irregular
Dreaming	Can happen, but less vivid	Most dreaming happens here
Muscles	Relaxed	Arms and legs temporarily paralyzed

Neither stage is more important. They do different jobs. According to NINDS, storing memories most likely requires both non-REM and REM sleep.

Why Deep Sleep Matters

Feeling refreshed

Deep sleep is the stage NINDS links most closely to waking up refreshed. That is why missing it can leave you groggy even after a full night in bed.

Memory and learning

NINDS says that without sleep, you cannot form or maintain the pathways in your brain that let you learn and create new memories. Lack of sleep also makes it harder to concentrate and respond quickly.

Brain “housekeeping”

Your brain stays active while you sleep. NINDS reports that recent findings suggest sleep plays a housekeeping role, removing toxins that build up in your brain while you are awake. Scientists are still studying how this works.

A small study by researchers at the National Institutes of Health (NIH) looked at this question. They scanned the brains of 20 healthy adults aged 22 to 72, once after a full night of rest and once after about 31 hours without sleep. After the sleepless night:

• Beta-amyloid, a waste protein linked to Alzheimer’s disease, rose by about 5%
• The increase showed up in the thalamus and hippocampus, areas that are vulnerable early in Alzheimer’s disease
• People with larger increases reported worse mood

This was a small study of one night of total sleep loss. It does not show that poor sleep causes Alzheimer’s disease. NIH also notes the link is thought to go both ways, since a build-up of beta-amyloid may itself cause trouble sleeping.

Long-term health

NINDS states that a chronic lack of sleep, or poor-quality sleep, increases the risk of high blood pressure, cardiovascular disease, diabetes, depression, and obesity.

How to Get More Deep Sleep: 9 Evidence-Based Tips

No habit can guarantee a set amount of deep sleep. Your body decides how much you get. But these steps, based on guidance from NINDS, the NHLBI, the CDC, and Cleveland Clinic, remove the most common things that get in its way.

1. Keep the same sleep schedule every day

NINDS advises going to bed and waking up at the same time each day. The NHLBI adds that staying up late and sleeping in on weekends can disrupt your body clock. It suggests keeping weeknight and weekend sleep times within about an hour of each other. Learn more about how your circadian rhythm affects sleep and energy.

2. Protect the first half of your night

Most deep sleep comes early in the night. If you often go to bed very late, or your sleep is cut short, you may lose some of the time when deep sleep is most likely. A regular, reasonable bedtime helps protect it.

3. Exercise most days, but not right before bed

NINDS recommends at least 30 minutes of exercise on most days of the week, but not within a few hours of bedtime.

4. Keep your bedroom cool

Cleveland Clinic sleep psychologist Michelle Drerup, PsyD, says temperature control is very important for staying in restorative, slow-wave sleep. Cleveland Clinic suggests a bedroom temperature of 60 to 67°F (15 to 19°C) for adults. Above about 70°F is too hot. A fan and lightweight bedding can help. See our guide to the best bedroom environment for sleep.

5. Make your room dark and quiet

NINDS notes that light exposure can make it hard to fall asleep and to get back to sleep if you wake up during the night. The NHLBI recommends keeping your bedroom quiet, cool, and dark. Cleveland Clinic sleep specialist Brian Chen, MD, suggests blackout curtains, earplugs, or white noise to block light and sound.

6. Cut off caffeine early

NINDS explains that a brain chemical called adenosine helps make you feel sleepy, and caffeine works by blocking it. The NHLBI says the effects of caffeine can last up to 8 hours. If you go to bed at 11 p.m., aim for no caffeine after about 3 p.m.

7. Skip alcohol before bed

The UK’s National Health Service (NHS) says alcohol may help you fall asleep, but you sleep less deeply after drinking. You may feel tired the next day, even after a full 8 hours. Read more in why you can still be tired after 8 hours of sleep.

8. Keep screens out of the bedroom

NINDS advises not watching TV or using a smartphone or computer in your bedroom. The CDC recommends turning off electronic devices at least 30 minutes before bedtime. Our article on how screen time affects sleep explains why.

9. Wind down before bed and keep naps short

NINDS suggests relaxing before bed with a warm bath, reading, or another calming routine. Try our 60-minute night routine. If you nap, the NHLBI says adults should nap for no more than 20 minutes. If you have trouble falling asleep at night, limit naps or take them earlier in the afternoon.

Why Am I Not Getting Deep Sleep? 8 Common Reasons

If you feel like you rarely get deep sleep, one or more of these factors may be the reason.

1. Age. The NHLBI says slow-wave sleep peaks in early childhood and drops sharply in the teenage years. It keeps decreasing through adulthood, and older people may have little or none. This is a normal change, not usually a sign that something is wrong.
2. Alcohol. The NHS says you sleep less deeply after drinking alcohol.
3. A warm bedroom. Cleveland Clinic notes that temperature control matters for staying in slow-wave sleep, and that a room above about 70°F is too hot.
4. Light and noise. NINDS says light exposure can make it hard to fall asleep and get back to sleep after waking.
5. Late caffeine. Caffeine blocks adenosine, the chemical that helps you feel sleepy. Its effects can last up to 8 hours.
6. Short or irregular sleep. Late nights cut into the first half of the night, when most deep sleep happens. An irregular schedule can also disrupt your body clock. Missed sleep adds up over time, as our guide to sleep debt explains.
7. Stress, medicines, and health conditions. NINDS lists medical conditions, medicines, stress, sleep environment, and age among the factors that affect your sleep.
8. A sleep disorder. The NHLBI says sleep apnea makes your breathing stop and restart many times during sleep. If it is not treated, you may not get enough quality sleep.

Signs You’re Not Getting Enough Deep Sleep

It is important to be clear here: there is no single sign you can feel that points only to low deep sleep. Most research looks at sleep loss overall, because it is hard to remove one stage without affecting the others. Only a sleep study can show how much time you spend in each stage.

But since deep sleep is the stage you need to feel refreshed, these signs suggest your sleep, including deep sleep, may not be doing its job:

• You wake up unrefreshed, even after 7 or more hours in bed
• You feel sleepy or tired during the day, even after getting enough sleep. The CDC lists this as a sign of poor sleep quality.
• You wake up again and again during the night. The CDC also lists this as a sign of poor sleep quality.
• You have trouble concentrating or reacting quickly. NINDS says lack of sleep makes both harder.
• Someone tells you that you snore loudly or gasp for air in your sleep. The NHLBI says this is worth raising with your healthcare provider, as it can be a sign of sleep apnea.

If these signs sound familiar, start with the 9 tips above and keep a simple sleep diary for two weeks. If nothing improves, talk to a doctor.

How Much Deep Sleep Do You Need?

Official guidance sets a target for total sleep, not for deep sleep. The CDC recommends 7 or more hours a night for adults aged 18 to 60. NINDS says most adults need 7 to 9 hours.

If you sleep long enough and without many interruptions, your body normally sorts out the stages for you. Your body also adjusts after short nights. NINDS explains that your sleep drive gets stronger every hour you are awake, and it causes you to sleep longer and more deeply after a period without sleep.

Can a Sleep Tracker Measure Deep Sleep?

Many watches and apps show a nightly “deep sleep” number. NINDS describes these devices as tools that informally collect data about your sleep, such as movement, sounds, heartbeat, and breathing.

A sleep study (polysomnogram) is different. It records brain waves, breathing, oxygen levels, eye and limb movements, and heart rate. NINDS says this data can show whether you are reaching and moving through the sleep stages properly.

Use tracker numbers as a rough guide to trends over weeks, not as a diagnosis. How you feel during the day is a more useful measure than one night’s reading.

When to See a Doctor

NINDS advises seeing a doctor if you have problems sleeping or feel unusually tired during the day. It notes that most sleep disorders can be treated effectively.

Talk to a healthcare provider if:

• You regularly sleep 7 or more hours and still wake up unrefreshed
• Daytime tiredness affects your work, driving, or daily life
• Someone says you snore loudly or gasp for air during sleep
• Better sleep habits have not helped after a few weeks

Your provider may ask you to keep a sleep diary or recommend a sleep study to check your sleep stages.

Frequently Asked Questions

How can I get more deep sleep naturally?

Keep the same sleep and wake times every day, exercise most days but not close to bedtime, avoid caffeine late in the day and alcohol before bed, and keep your bedroom cool, dark, and quiet. A regular bedtime protects the first half of the night, when most deep sleep happens.

Why am I not getting deep sleep?

Common reasons include alcohol, a warm bedroom, late caffeine, light and noise, short or irregular sleep, stress, and some medicines. Deep sleep also decreases naturally with age. A sleep disorder such as sleep apnea can also reduce sleep quality.

What are the signs of not getting enough deep sleep?

There is no sign that points only to low deep sleep. But waking up unrefreshed, feeling sleepy during the day, waking often at night, and trouble concentrating all suggest your sleep is not as restful as it should be. Only a sleep study can measure your sleep stages.

How much deep sleep do I need?

There is no official target for deep sleep alone. Guidance focuses on total sleep. The CDC recommends 7 or more hours a night for adults aged 18 to 60. If you sleep long enough without many interruptions, your body usually manages the stages.

When does deep sleep happen?

Mostly in the first half of the night. REM sleep takes up more of the second half.

Does deep sleep decrease with age?

Yes. According to the NHLBI, slow-wave sleep peaks in early childhood, drops sharply in the teenage years, and keeps decreasing through adulthood. This is a normal change.

Does alcohol affect deep sleep?

Yes. The NHS says alcohol may help you fall asleep, but you sleep less deeply afterward and may feel tired the next day, even after a full 8 hours.

Is deep sleep or REM sleep more important?

Neither. They do different jobs, and NINDS says storing memories most likely requires both.

Are sleep trackers accurate for deep sleep?

Trackers estimate sleep stages from things like movement and heart rate. Only a sleep study, which records brain waves, measures sleep stages directly. Use tracker data to spot trends, not to diagnose a problem.

The Bottom Line

Deep sleep is the stage that leaves you feeling restored, and most of it happens early in the night. You cannot switch it on, but you can protect it. Keep a steady schedule, stay active, cut late caffeine and alcohol, and sleep in a cool, dark, quiet room. If you still wake up unrefreshed, talk to a doctor. For a complete plan, see our 12 tips to improve sleep quality naturally.

Sources

1. National Heart, Lung, and Blood Institute. How Sleep Works: Sleep Phases and Stages.
2. National Institute of Neurological Disorders and Stroke. Brain Basics: Understanding Sleep.
3. National Institutes of Health. Sleep deprivation increases Alzheimer’s protein.
4. National Heart, Lung, and Blood Institute. Healthy Sleep Habits.
5. Centers for Disease Control and Prevention. About Sleep.
6. National Health Service (UK). Self-help tips to fight tiredness.
7. Cleveland Clinic. What’s the Best Temperature for Sleep?
8. National Heart, Lung, and Blood Institute. What Is Sleep Apnea?
9. Cleveland Clinic Newsroom. Best Bedroom Temperature for Sleep.

This article is for general information only and is not medical advice. It cannot diagnose any condition. Always talk to a qualified healthcare provider about your health. Read our full Disclaimer.