Sleep of sufficient duration and quality is a crucial pillar of our health. In this post, you will learn about the functions of sleep, the different sleep stages, and how you can improve your ability to fall and stay asleep with a few recommendations for a healthy sleep.
What Defines A Healthy Sleep
Good sleep is characterized by both quality and sufficient duration. The optimal amount is about 7 hours of sleep for adults, though this varies based on individual needs, life stages, and lifestyle. Falling asleep should ideally take no longer than 30 minutes. A shorter time to fall asleep is often associated with better health— the healthier you are, the faster you fall asleep. However, this can’t be generalized for everyone, just like the ideal sleep duration.
The most important thing is that you feel refreshed and rested in the morning, even if it takes a bit of time to get going. Healthy sleep is not a given— in Germany, one in three people report that they perceive their sleep as moderate or even poor, with working individuals being more frequently affected. Often, the well-known “thought carousel” prevents people from falling asleep, especially when they are struggling mentally. Chronic poor sleep can have health consequences and, for example, contribute to the development of depression.
Functions of Sleep
Sleep performs essential functions for the human body and mind. While we sleep, our immune system is strengthened. Important learning and memory processes also occur during sleep. Our brain uses this rest period to review and reinforce what was learned during the day. Impressions and information we absorb during the day are transferred to long-term memory and stored there permanently while we sleep.
But it’s not just our memory that benefits from a healthy sleep: harmful substances are broken down, wound healing and cell regeneration are activated. Additionally, growth and repair processes are triggered during sleep. This occurs through the release of growth hormones, which stimulate processes like muscle growth. Therefore, sufficient and good sleep is not only restorative but also a central building block for our physical and mental health.
Sleep Stages
The human sleep cycle is a fascinating interplay of different stages that repeat multiple times during the night. A typical cycle lasts between 90 and 110 minutes and consists of three non-REM stages and one REM (Rapid Eye Movement) stage. There are also brief periods of wakefulness, which last only a few seconds.
N1: Falling Asleep
The N1 stage marks the transition from wakefulness to sleep. It is quite short, lasting only a few minutes. In this phase, muscle activity decreases, eye movements slow down, and you can be easily awakened.
N2: Light Sleep
The N2 stage, also known as light sleep, follows. In this phase, heartbeat and breathing become more regular, body temperature drops, and eye movements cease. Interestingly, we spend the majority of our sleep time in this phase.
N3: Deep Sleep
Next comes the deep sleep or N3 stage. This is a particularly important phase for physical recovery and a healthy sleep. It is difficult to wake someone during this phase. The body uses this time to regenerate, strengthen the immune system, and release growth hormones. There is neither eye movement nor muscle activity.
REM Sleep
Finally, we reach REM sleep, characterized by rapid eye movements. Most of our dreams occur during this phase, and brain activity resembles that of wakefulness. However, the body is in a state of paralysis, meaning that the large muscles are inactive, and heartbeat and breathing become irregular.
Power Naps
A power nap, a short nap during the day, can be quite beneficial. This brief rest provides recovery and can boost concentration and performance. Power naps are especially helpful for memory, as demonstrated by a study conducted by researchers at Saarland University. However, a power nap should not last longer than 20 to 30 minutes, as you might enter a deeper sleep, making it harder to wake up afterward. For those who have trouble falling asleep at night, power naps are not recommended as they can further disrupt the sleep-wake cycle.
Sleep Hygiene: Healthy Sleep Through Better Habits
To promote healthy sleep, sleep hygiene is crucial. Here are a few recommendations to help you fall and stay asleep:
- Avoid watching TV before bed, especially falling asleep in front of the TV. A quick nap in front of the screen can leave you feeling more awake than before, making it harder to fall asleep again.
- No social media before bed: The light from screens blocks the release of the sleep hormone melatonin, and scrolling through constantly new content is more stimulating than calming.
- Try to maintain a consistent sleep-wake schedule by going to bed and waking up at the same time during the week and, ideally, on weekends too.
- The bedroom should primarily be a place of rest. Arrange it accordingly and ensure that noise and light are kept out. The temperature should be around 16°C (60°F).
- Just as the bedroom should be primarily for sleeping, the bed should only be used for sleep. Avoid eating, reading, or engaging in other activities in bed. Your bed should signal to your brain: it’s time to sleep.
- If you have trouble falling or staying asleep, get up, leave the room, and read, for example. Only go back to bed when you start feeling sleepy.
- Don’t eat too heavily in the evening: An active digestive system can disrupt sleep. Protein-rich and low-carb meals are recommended for dinner.
- Avoid (excessive) alcohol: While alcohol might subjectively make you feel like you’re sleeping better, the resulting sleep is often less deep and includes fewer deep sleep and REM phases.
- Don’t check the time when you wake up at night. This avoids negative thoughts like “only so little time left” and prevents the pressure to fall asleep— which is anything but helpful.
