As an essential component to well-being, sleep is divided into four sleep stages that help your body and mind recharge every night.
Stage 3 non-REM sleep marks the deep sleep phase that your body requires to feel refreshed in the morning.
To improve deep sleep, you need to improve your overall restful sleep by following a healthy lifestyle and practicing good sleep hygiene habits.
Certain ingredients and nutrients help support better sleep, including Melatonin, Typtophan, B Complex Vitamins, Omega-3, Vitamin D, and Magnesium.
Did you know that humans can survive longer without food or water than without sleep?  While scientists continue to study the intricacies of sleep’s effect on the body, experts underscore how sleep helps you recharge both mentally and physically. Sleep benefits range from (supporting or maintaining) overall health, immunity, as well as helping to maintaining a healthy weight and normal cognitive functioning. 
On the flip side, poor sleep (especially chronic sleep loss) can result in both short-term and long-term health issues. Sleep deprivation can lead to lack of alertness, excessive daytime sleepiness, relationship stress, impaired memory, and quality of life.
And, while allsleep is beneficial, one key stage—deep sleep—provides the most restorative sleep. But what is deep sleep? More importantly, how can you get more of it?
Read on for tips on how to increase deep sleep.
What Is Deep Sleep?
Your body’s ability to sleep or wake depends on the proper functioning of your internal clock known as the circadian rhythm. As part of this cycle, the body produces Melatonin (a sleep-promoting hormone) that increases as it gets dark and decreases as it gets light.
Once you’re no longer awake, sleep fluctuates throughout the night in several sleep cycles made up of four different stages. The two primary types of sleep include rapid eye movement (REM) sleep and non-rapid eye movement (non-REM) sleep. In each phase, brain activity including specific brain waves and neuronal activity occur.  It takes roughly 90 to 110 minutes to complete a full sleep cycle.  Generally, you progress through four to six rounds of sleep cycles every night.  Truly restorative sleep involves moving smoothly from one stage of the sleep cycle to the next, with increasingly longer, deeper REM segments happening near the morning. 
The four stages of sleep include: [4,5,6]
Stage 1: Non-REM sleep(also called NREM or N1) Duration: 1-5 minutes NREM sleep occurs first and includes three stage In this short, light sleep phase, you transition from wakefulness to sleep. Your muscles relax and your body functions (i.e., breathing, eye movements, heart rate) slow down.
Stage 2: Non-REM sleep(also called N2) Duration: 10-60 minutes This non-REM sleep stage starts with light sleep then transitions to deeper sleep. Your muscles further relax, body functions slow down (including brain activity), body temperature decreases, eye movements stop. Although specific brain wave patterns called sleep spindles can occur in any NREM sleep stage, they’re most prevalent in stage 2. As you transition through repeated sleep cycles, you spend more time in stage 2 sleep than in any other sleep stage. These last two stages of non-REM sleep are when you sleep deeply, and this sleep depth makes it harder to wake up from this stage of sleep.
Stage 3: Non-REM sleep(also called N3, slow-wave sleep, delta sleep, or deep sleep) Duration: 20-40 minutes Stage 3 sleep marks the deep sleep phase that your body requires to feel refreshed upon waking. During the first half of the night, stage 3 lasts longer than in subsequent sleep cycle Your muscles further relax, body functions slow down to their lowest levels during sleep. During this phase, your brain produces very slow brain waves called delta waves. It’s difficult to awaken during stage 3 sleep.
Stage 4: REM sleep Duration: 10-60 minutes Initially occurring about 90 minutes after you fall asleep, stage 4 is often the phase when you have vivid dreams. Your muscles are temporarily paralyzed, which is a good thing—this keeps you safe so you can’t act out your dreams. Your body functions also become faster (i.e., breathing, eye movements, heart rate, blood pressure, brain wave activity), increasing almost to the levels of when you’re awake. As you get older, you spend less time in the REM sleep stage.
FYI: Do you ever wake up feeling groggy? It’s very common and it even has a special name—sleep inertia.
In general, most adults need between seven to nine hours of quality sleep every night. The body self-regulates amounts of deep sleep, spending between 13-23 percent of total sleep in that deep sleep stage.  To improve deep sleep, you need to improve your overall sleep.
Getting a good night’s sleep involves much more than just going to bed at night. Taking a holistic approach to improving your sleep works best. This means following a healthy lifestyle and practicing good sleep hygiene. While you can take many steps to support your sleep pattern, the “top five” can make a big difference in improving sleep: [9,10,11,12,13]
Establish a consistent bedtime schedule and routine. Go to bed and wake up at the same time every day. Create a sleep routine (such as taking a warm shower, reading, or meditating) to help signal your body that it’s time to prepare for sleep.
Get natural light exposure. Remember how your sleep/wake cycle affects the production of Melatonin? Studies show that spending time in natural light helps your body’s circadian rhythm adjust to sleeping better at night. Spending time in natural light during the daytime signals your body to stay awake and active. As nighttime nears and your environment grows darker, it alerts your internal clock to slow down and prepare for sleep.
Watch your diet. Don’t eat large meals within two to three hours before bedtime to allow time for digestion. If you’re hungry, eat lighter snacks near bedtime. Limit both caffeine and alcohol near bedtime, as both can disrupt your sleep quality. And don’t drink too much of any liquid near bedtime, as this could result in more frequent trips to the bathroom.
Limit screen-time before bed. The blue light emitted from your TV, laptop, and other electronic devices trick your mind into thinking it’s daytime. This could impact the body’s production of Melatonin.
Create a comfortable sleep environment. Dim the bedroom lights and close the blinds to help cue the body that it’s time to go to sleep. Keep your room at a comfortable temperature. Invest in the best mattress you can afford along with comfortable pillows and soft bedding to support your body and promote a restful slumber. Reduce the noise in your environment. Some people find it helpful to listen to soft music, nature sounds, or even “pink noise” (sound waves that enhance deep sleep and memory). 
A balanced, healthy diet should include plenty of fruits and vegetables, whole grains, lean proteins, healthy fats, and low-fat dairy. Consuming certain ingredients or nutrients, in particular, can really support healthy sleep. These include: 
Melatonin: A sleep hormone that is found in certain fruits (tart cherries, grapes, strawberries, and kiwi), nuts (pistachios and walnuts), and veggies (bell peppers, corn, and tomatoes). A dietary supplement, like Melatonin, may also help you naturally fall asleep†
Tryptophan: An amino acid the body needs to produce serotonin and Melatonin and found in protein foods such as nuts and seeds, beans, cheese, eggs, oats, poultry, red meat, and tofu.
B Complex Vitamins: The eight B vitamins include Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Biotin (B7), Folate (B9) and Cobalamin (B12). B vitamins are found in foods like beans, dairy, eggs, leafy greens, meat, poultry, and salmon.
Omega-3: This heart-healthy fatty acid is found in fatty fish, nuts, and seeds.
Vitamin D: This essential nutrient is found in egg yolks, fortified foods (like milk and cereal), and mushrooms.
Magnesium: This key mineral is found in bananas, beans, nuts, seeds, tofu, and whole grains.
Most adults need seven to nine hours of sleep each night. Sleep is categorized as REM sleep and non-REM sleep and divided into four distinct stages. The deep sleep (or restorative sleep) stage is found in stage 3 non-REM sleep. The key for how to increase deep sleep lies in improving total sleep. You can do a lot to improve both your sleep quantity and sleep quality by following a healthy lifestyle, practicing good sleep hygiene, and including certain sleep-promoting nutrients in your healthy eating.
Continue to check back on the Nature Made blog for the latest science-backed articles to help you take ownership of your health.
This information is for educational purposes only and is not intended to serve as medical advice. Consult your health care provider for more information.
† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
Lisa Beach is a seasoned journalist whose work has been published in The New York Times, Good Housekeeping, Eating Well, Parents, AARP’s Disrupt Aging, Optimum Wellness, and dozens more. She also writes for a variety of health/wellness-focused brands. Check out her writer’s website at www.LisaBeachWrites.com.
Lynn is a Registered Dietitian (R.D.) and is a member of the Medical and Scientific Communications team at Pharmavite. She has over 20 years of experience in integrative and functional nutrition and has given lectures to health professionals and consumers on nutrition, dietary supplements and related health issues. Lynn frequently conducts employee trainings on various nutrition topics in addition to educating retail partners on vitamins, minerals and supplements. Lynn has previous clinical dietitian expertise in both acute and long-term care, as well as nutrition counseling for weight management, diabetes, and sports nutrition. Lynn earned a bachelor’s of science in Nutrition with a minor in Kinesiology/Exercise Science from The Pennsylvania State University. She earned a M.S. degree in Human Nutrition from Marywood University in Scranton, Pennsylvania. Lynn is an active member of the Academy of Nutrition and Dietetics, Sports Cardiovascular and Wellness Nutritionists, Dietitians in Functional Medicine, and holds a certification in Integrative and Functional Nutrition through the Academy of Nutrition and Dietetics.