Deep sleep explained

Imagine an opportunity for the body to stay almost completely still. Outside noise becomes less of a bother, and internal systems begin work on preparations and repair. If it sounds satisfying, that’s because it usually is. It’s how the experts describe deep sleep, and it’s one of the most important periods in the body’s 24-hour clock. Interested in learning more? Continue on for details about this very important stage of sleep.

In this article

What is deep sleep?

Deep sleep typically occurs during the first half of the night. It’s when the body gets to mend tissues, build bones and get its energy back up. Brain activity also slows down significantly during this stage. The muscles relax, breathing becomes slower, and the heart rate decreases. It can be difficult to wake someone up in this state. If it does happen, they’ll likely rise feeling groggy and disoriented.

Deep sleep vs. rapid eye movement (REM) sleep

There are four stages of sleep. Deep sleep takes place during the third stage. REM sleep comes next in the cycle, and it has markedly different effects on the body. During REM, the eyes move quickly in different directions, and the brain becomes very active. Heart rate and breathing fluctuate, and brain waves look a lot like they do when someone is awake. One thing REM does have in common with deep sleep is that it keeps the body almost completely still. But here’s the catch: REM only does so to keep people from acting out their dreams.

Benefits of deep sleep

Deep sleep offers several important benefits for both the body and brain:

• Balanced hormones. The body releases growth hormones during deep sleep. This helps with growth and development, especially in children and teens.
• Clearer thinking. Regular deep sleep helps people focus and make better decisions. This can lead to better performance during daily tasks.
• Improved immune function. Deep sleep supports the immune system, which can help the body fight off illnesses and infections.
• Improved mood. Getting enough deep sleep can help to improve mood and emotional health.
• Increased energy. Deep sleep allows the body to preserve energy, which helps people feel awake and alert during the day.
• Consolidate memories. Deep sleep plays an important role in forming long-term memories and processing information from the day.
• Physical repairs. During deep sleep, the body heals and builds bones. This helps people recover from daily wear and tear.

If someone feels as though they aren’t getting these benefits, it could mean they aren’t getting enough deep sleep.

How much deep sleep do people need?

The amount of sleep people need depends on their age and other factors. Infants, for instance, need a lot of deep sleep to help their brains develop and bodies grow. The same applies to children growing into teenagers, though they don’t require quite as much rest as newborn babies. But once people grow up, their need for deep sleep decreases dramatically.

Sleep disruptors (and ways around them)

Deep sleep is incredibly important for overall health. But it’s often interrupted by things like stress, noise and screen time. The good news is that there are easy ways to help protect this essential stage of sleep.

Stress and anxiety. Stress can fragment sleep, making it hard to enter and stay in deep stages of sleep.

Helpful tips: People can incorporate relaxation techniques like meditation to help reduce anxiety. They can also take a warm bath before bed to soothe muscles and ease the mind.

Screens in the bedroom. Blue light from devices (including smartphones, tablets and computers) can interfere with melatonin production.

Helpful tips: People can use blue light filters on devices during the evening and avoid screens for at least an hour before bed. They can also enjoy screen-free activities like reading a book to help them wind down.

Diet and exercise. Certain foods can cause discomfort during sleep, while a lack of exercise can throw off the body’s internal clock.

Helpful tips: Troubled sleepers should avoid heavy, fatty or spicy meals before bed. They should also work out earlier in the day and stick to yoga or gentle stretching near bedtime.

Environmental factors. Noise and light can interrupt deep sleep, leading to fewer restful nights.

Helpful tips: People can use a white noise machine to mask disruptive sounds. They can also block out unwanted light with blackout curtains or an eye mask. Ensuring sleep environments are dark and quiet can also help people achieve uninterrupted, high-quality sleep.

Consistent bedtime routine. Without any routine, peaceful and restful sleep can be difficult to achieve.

Helpful tips: People should maintain a regular sleep schedule by going to bed and waking up around the same time every day, even on weekends. They can also start incorporating certain activities before bed that signal it’s time to sleep.

Techniques to help improve sleep

Certain strategies can help some people achieve deep sleep, but they might not work for everyone. If someone is having a hard time getting enough rest, they should contact a health care provider for support.

The 10, 3, 2, 1, 0 method

The 10, 3, 2, 1, 0 method can help improve sleep quality and establish a better bedtime routine. Here’s how to break it down:

• 10: The last sip of caffeine should take place 10 hours before heading to bed. It’s important to check labels of medications and other products as well; these items may contain enough caffeine to disrupt sleep.
• 3: People should stop eating food or drinking alcohol at least 3 hours before bedtime. Eating within this time period can make it harder to fall asleep and stay asleep.
• 2: People should stop working 2 hours before bed. Instead, they should look for opportunities to relax the mind and prepare for bed. Reading a book, taking a warm bath or practicing meditation are all good options.
• 1: It’s best to avoid screens (like phones, tablets, televisions and computers) for a full hour before bed. These devices emit blue light, which can disrupt the sleep cycle.
• 0: Come morning, people should avoid hitting the snooze button altogether. It’s a bad morning habit, and one that can impact someone’s ability to fall asleep come bedtime.

The military method

The military method for sleep is a technique designed to help individuals fall asleep quickly, even in stressful or challenging environments. Here’s how to get started:

1. Relax the face. People should start relaxing the muscles in the face, including the jaw, tongue and the muscles around the eyes.
2. Relax the shoulders. People should drop their shoulders as low as possible, then relax the upper and lower arms, one side at a time.
3. Relax the chest and legs. People can relax the chest, then move down to the thighs and calves. They should let each muscle to relax and let go of tension.
4. Breathe deeply. People can take a deep breath and exhale slowly. They should focus on the feeling of air moving in and out of the body.
5. Clear the mind or visualize a peaceful scene. People should clear their minds of all thoughts for 10 seconds. If this is hard, they can think of a peaceful scene, like a quiet beach or a calm forest.

Progressive muscle relaxation (PMR)

PMR is designed to help ease stress and anxiety before bed. The technique involves tensing various muscle groups in the body, then relaxing them. The idea is that this cycle of tension and relaxation can help soothe the mind. Here’s how it works:

1. Find a comfortable place. PMR should be done sitting or lying down in a quiet, comfortable place without any disturbances.
2. Tense certain muscles and hold in. People can start with the feet and work up toward the head (tensing each muscle group for about 5 seconds).
3. Relax each muscle group. People should release the tension suddenly and let their muscle go limp.
4. Focus on breathing. People shouldn’t hold their breath as they tense their muscles. This can actually cause more stress on the body. Instead, it’s best to breathe in when creating the tension and breathe out when it gets released.
5. Focus on the contrast. Pay attention to the differences between the feelings of tension and relaxation in each muscle group.
6. Repeat. Move to the next muscle group and repeat the process. Common muscle groups include the hands, arms, forehead, eyes and jaw.

Key takeaways

Deep sleep is an important part of the sleep cycle when the body gets a chance to repair itself and refuel for the next day. But things like stress, noise and even diet can interrupt this process. To help improve sleep quality, people should optimize sleep hygiene methods, such as trying to go to bed at the same time every night, creating a comfortable sleep environment and avoiding screens before bed. Managing stress and practicing relaxation techniques can also help.