How much deep sleep do you need during the night?

If you use a sleep sensor or a vibration bracelet, you will receive some data about your sleep. Among other things, most models record how long the individual sleep phases last .

The total sleep should be about 6 to 8 hours. Then most people feel rested the next morning and have spent the night rested. But what does it look like in detail? How much deep sleep is normal and do you need?

You go through different phases during sleep These can be roughly divided as follows:

Sleep phase
Moderately light sleep
Transition to deep sleep
Deep sleep
REM sleep

The deep sleep is doing a special meaning to. During the day, the body and mind are exposed to great stress. You want to achieve top performance in your job and this demands the brain. Stress arises and it is important to find a balance.

If you also do sport or are on the move a lot, muscles and tendons also have to regenerate. This mainly takes place in deep sleep .

The important regeneration processes take place in this phase . The muscles are intensively supplied with nutrients, the damaged cells are repaired and the body is prepared for renewed stress.

To achieve this, the body releases the necessary hormones during deep sleep . These are essential for cell regeneration and strengthen health . The immune system is also active during deep sleep to fight viruses or bacteria, for example. If you suffer from a cold, a good night’s sleep is important in order to overcome the illness as quickly as possible.

The great importance of deep sleep can be derived from these properties . If this sleep phase is shortened, this represents a severe impairment, the consequences of which will be explained in the later chapter.


The deep sleep phase is reached around 20 to 30 minutes after falling asleep. This can be proven very precisely in the sleep laboratory using the EEG currents. With the help of the currents, brain activity is measured.

While a relatively high and noticeable brain activity can be observed when falling asleep, this looks completely different in deep sleep. Here the EEG curve is significantly flatter and overall calmer .

In this phase , the brain processes what it has learned and the experiences gained during the day. Therefore, this period is especially important for the development of babies and children.

The phases of sleep alternate regularly during the night. The deep sleep is interrupted by the REM phase. During the entire night, the deep sleep and REM phase will go through an average of four to six times.


It is incorrect that deep sleep and REM sleep alternate throughout the night. After a certain amount of sleep, the body prepares to wake up . The hormone cortisol is released for this purpose This hormone inhibits deep sleep and leads to easier sleep.

Specifically, this means that deep sleep often only occurs twice during the night. The first deep sleep phase is the longest. During the night, you are likely to be in deep sleep much less than you thought.

Because only around 15 to 25 percent of sleep is characterized by deep sleep. If you sleep 8 hours a night, this results in a duration of a little more than 1 hour up to 2 hours. If you sleep much shorter, deep sleep is also affected.


The consequences of too short a deep sleep are dramatic and largely coincide with the symptoms of lack of sleep .

Increased tiredness

The night should actually serve you to recover from the exertions of the day. If sleep is too short and insufficient, this affects all regeneration processes. In the morning you will feel the need to lie down again and go back to sleep. Your body is actually not ready to start the day and only with coffee can you somehow get yourself to overcome your weaker self. Nevertheless, you will be much more tired and less rested throughout the day .

Lower efficiency

Your performance also suffers from tiredness. This affects both the mental and physical level. It falls you to concentrate hard to beat and the mind wanders frequently. This is not surprising, because your brain was unable to process the experiences and insights properly. This creates a certain chaos in the head , which affects your performance.

Weakened immune system

If you sleep too short for a long time, you will suffer from infectious diseases more often. Your body does not manage to fight the pathogens and especially in winter you feel sick more often. Deep sleep is important for a healthy immune system and prevents pathogens from gaining the upper hand.


There is no general answer to the question of how much deep sleep you need now This varies from person to person and depends largely on their lifestyle. If you expect your body to be more stressful, it will ask for a longer period of sleep. This can happen, for example, because of your sporting activity or because you like to consume alcohol.

If you lead a healthy lifestyle and are exposed to relatively little stress, the indicated 1 to 2 hours of deep sleep will be sufficient . With these you will get up well rested in the morning and access your full performance potential.

Whether you have a lack of deep sleep can be easily determined using the symptoms described . These look like this:

Increased tiredness
Difficulty concentrating
Increased aggression
Delayed development in babies and young children

If you feel rested in the morning and fully recovered , your deep sleep will be long enough. Usually, however, 1 to 2 hours of deep sleep is a good guideline.

If you notice a high deviation with your sleep tracker, you should ask yourself whether there are health problems and then improve your sleep. Otherwise, a shorter or longer deep sleep is not a problem.

Jamie Clark

Hello, I’m Jamie Clark, 32 years old, and I have been living in the USA for a few years.
Since I was a child, I have suffered from a house dust allergy, severely affecting me. I felt the effects both while exercising and while sleeping. Constant sneezing after getting up and difficult breathing were the consequences. The allergy has also developed into asthma, which is still a sporting restriction today.

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