The 4 Stages of Sleep and How to Get Better Sleep

We go through different stages of sleep, each playing a crucial role in ensuring our mind and body wake up refreshed. Understanding the sleep cycle also helps explain how certain sleep disorders can affect one’s sleep and overall health. Let’s explore the 4 stages of sleep and discover ways to improve your sleep in the following article.

1. How Many Stages Does the Sleep Cycle Have?

There are different stages of sleep, and it’s normal for these stages to change as you sleep through the night. The first sleep cycle is typically the shortest, lasting between 70 to 100 minutes, while subsequent cycles tend to last between 90 to 120 minutes.

The sleep cycle can vary for each person and night, depending on factors such as age, recent sleep patterns, and alcohol consumption. Currently, sleep is divided into 4 stages, including one stage of Rapid Eye Movement (REM) sleep and three stages of Non-REM (NREM) sleep. These stages are identified through the analysis of brain activity during sleep, which shows distinct patterns characteristic of each stage.

1.1. NREM Sleep

NREM sleep is divided into three different stages of sleep, including:

• Stage 1

Stage 1, also known as N1, is essentially when a person first falls asleep. This stage usually lasts from one to seven minutes.
In N1 sleep, the body is not yet fully relaxed, although bodily and brain activities begin to slow down with short periods of movement. There are slight changes in brain activity associated with the process of falling asleep during this stage.
It is very easy to wake someone in this sleep stage, but if a person is not disturbed, they can quickly transition to Stage 2. As the night goes on, an undisturbed sleeper may not spend much time in Stage 1 as they move on to subsequent sleep cycles.

• Stage 2

In Stage 2, or N2, the body enters a more subdued state characterized by a drop in temperature, relaxed muscles, and a slowing of breathing and heart rate. At the same time, brain waves display a new pattern, and eye movement stops. Overall, brain activity slows down, but there are short bursts of activity that actually help resist being awakened by external stimuli.
Stage 2 sleep can last from 10 to 25 minutes during the first sleep cycle, and each N2 stage may become longer as the night progresses. Generally, a person spends about half of their total sleep time in Stage 2.

• Stage 3

Stage 3 of sleep, also known as N3 or deep sleep, makes it harder to wake someone if they are in this stage. Muscle tone, pulse, and breathing decrease during N3 sleep as the body relaxes even further.
Brain activity during this stage has a recognizable pattern called delta waves. For this reason, Stage 3 is also referred to as delta sleep or slow-wave sleep (SWS).
Experts believe this stage is crucial for restorative sleep, allowing the body to recover and grow. It may also boost the immune system and other vital processes in the body. Although brain activity is reduced, there is evidence that deep sleep contributes to clear thinking, creativity, and memory.
You spend the most time in deep sleep during the first half of the night. In the early sleep cycles, Stage N3 typically lasts from 20 to 40 minutes. As you continue to sleep, these stages shorten, with more time allocated to REM sleep instead.

1.2. REM Sleep

During REM sleep, brain activity increases, nearing the levels observed when you are awake. At the same time, the body undergoes a state of atonia, which is a temporary paralysis of the muscles, except for two cases: the eyes and the muscles that control breathing. Although the eyes are closed, they can be seen moving rapidly, which is how this stage got its name.

REM sleep is believed to be essential for cognitive functions such as memory, learning, and creativity. REM sleep is known for the most vivid dreams, which is attributed to a significant increase in brain activity. Dreams can occur in any sleep stage, but they are less common and intense during NREM stages.

Under normal circumstances, you do not enter REM sleep until you have been asleep for about 90 minutes. As the night progresses, REM stages lengthen, especially in the latter half of the night. While the first REM stage may last only a few minutes, subsequent stages can last about an hour. Overall, REM stages account for about 25% of sleep in adults.

2. The Benefits of Adequate Sleep Cycles

From the previous section, we see that there are many different stages of sleep, and getting a sufficient amount of sleep that includes all stages offers numerous benefits to the body. While researchers are still exploring the roles and benefits of each sleep stage, deep sleep can have significant health advantages. Studies show that deep sleep helps individuals wake up refreshed, recover physically, and supports learning and memory formation.

• Quality deep sleep can help regulate several hormones in the body, including growth hormone and prolactin. Growth hormone enhances growth and metabolism, affecting many processes in the body. Meanwhile, prolactin contributes to breast development and milk production, making it an important hormone for pregnant women.
• Deep sleep also strengthens the immune system by supporting the hormonal changes necessary for the body to respond to foreign organisms or pathogens, helping to prevent illness and improve health.
• Researchers believe that the ability to promote learning and enhance memory formation is best achieved during NREM sleep stages. Although deep sleep may play a crucial role in memory formation, it is still unclear how deep sleep specifically impacts memory.
• Deep sleep also helps clear waste products from the brain. Waste products from cerebrospinal fluid that accumulate during the day can be cleaned up if you experience deep sleep. Deep sleep may be particularly important for eliminating waste products associated with the development of dementia.

3. How to Achieve Quality Sleep and Ensure Adequate Sleep Stages

The best way to get deeper sleep is to ensure you are getting enough total hours and to follow evidence-based tips for healthy sleep. Most deep sleep occurs during the first one to two hours of sleep. Therefore, a sleep routine that helps you fall asleep faster can also naturally lead to deeper sleep.
You can also cut out or limit things that make it difficult to sleep deeply. In some cases, you can make simple changes to help improve your sleep. However, you should consult your doctor if you believe that a medical condition or medication is affecting your sleep. Here are some ways to help you achieve deep and adequate sleep.

3.1. Go to Bed on Time

Try to maintain a consistent bedtime and wake-up time each day. While you may want to stay up late to work, play games, or sleep a little more on weekends and other days off, research shows that an inconsistent sleep-wake schedule can affect the human circadian rhythm. Keeping a regular sleep schedule helps people fall asleep faster, allowing them to get the deep sleep they need.

3.2. Relax and Manage Stress

You may find it difficult to sleep when you are under significant stress, pressure, and anxiety. Researchers have found that individuals with high stress not only struggle to fall asleep but also get less deep sleep. Calming activities that reduce stress can help people achieve deeper sleep.
Relaxation exercises, deep breathing, yoga, and meditation can naturally reduce anxiety and may improve sleep. Reading, listening to soft music, or taking a warm bath before bed can also help you relax and prepare for deep sleep. In addition to relaxing activities, you should try to avoid discussing or thinking about stressful topics before bed.

You should consult your doctor if stress and anxiety do not improve after self-care or significantly affect your life.

3.3. Avoid or Limit Caffeine and Alcohol

Caffeine and alcohol both reduce sleep quality and prevent deep sleep. Individuals looking to improve their sleep should avoid consuming caffeine and alcohol in the evening. However, those who regularly consume large amounts of alcohol should consult their doctor before significantly reducing or stopping their alcohol intake, as withdrawal can be dangerous.

3.4. Keep the Bedroom Comfortable

Individuals experiencing pain or discomfort often find it difficult to achieve deep sleep. Loud noises and bright lights in or near the sleeping environment can also make it hard to sleep deeply. You should keep your bedroom dark, quiet, and cool, with comfortable bedding and pillows for the best sleep. Trying to reduce noise with earplugs and block out light with blackout curtains can help those living in noisy or bright areas.

3.5. Consult Your Doctor

You should consult your doctor if you have sleep problems that do not improve after applying healthy sleep tips or if sleep disorders significantly affect your daily life. You should also talk to your doctor if you suspect that your sleep issues may be caused by a health condition or medication. If you experience sleep disorder issues, it is important to seek appropriate solutions for early treatment. Take proactive steps for your health early on to live a sharp and long life.

This article has helped you understand the four stages of sleep and ways to achieve deep and restorative sleep. Quality sleep will boost your immunity and overall health while enhancing your mood and memory. Therefore, if you are experiencing sleep disturbances, take proactive steps to care for your health and sleep early on to live healthier and longer.

References: Health.clevelandclinic.org, Sleepfoundation.org, Mayoclinic.org, Healthline.com, Sleepfoundation.org