The importance of the sleep phases

Our sleep is made up of several sleep cycles, in which we go through different sleep phases night after night. Find out here which sleep phases there are and what significance the individual sleep stages have for a restful night.

Table of contents

  1. How does our sleep work?
  2. The sleep phases at a glance
  3. The importance of sleep cycles
  4. Conclusion

How does our sleep work?

Our sleep is essential for our energy balance and numerous important recovery, repair and rebuilding processes in our brain, tissue and cells. Sufficient and restful sleep is therefore one of the most important foundations for a healthy functioning of the body and an efficient, healthy everyday life. Experts generally recommend that adults get 7 - 8 hours of sleep per night - and not by chance. Every night our sleep is made up of different sleep cycles, which in turn consist of different sleep stages: The falling asleep stage, light sleep stage, two deep sleep stages and REM sleep. To feel refreshed in the morning, it is of great importance to go through a sufficient number of sleep cycles and to give the body time to regenerate. We give you an overview of the different sleep stages and explain the importance of each stage for restful sleep.

The sleep phases at a glance

Schlafphasen je Schlafzyklus

Falling asleep phase

The fall asleep phase refers to the last few minutes before "real" sleep. During this phase, the body switches off, relaxes and comes to rest. For adults, the sleep phase lasts about 5-20 minutes.

    Light sleep phase

    During this period of sleep, our muscles relax, our pulse and breathing become more regular, and our body temperature drops. We spend just under half of our sleep time in this rather superficial sleep, in which we are still quite susceptible to external stimuli such as noise or light. On average, we reach the light sleep phase about 15 minutes after falling asleep.

    Deep sleep phase

    Das Tiefschlafstadium

    The light sleep stage is followed by deep sleep. It dominates the first third of the night and ensures that our body shuts down even further, heartbeat and breathing slow down and blood pressure drops. In this stage, known as slow wave sleep, the frequency of brain waves drops and neural activity is significantly reduced. Now the energy stores in our brain are recharged and numerous hormones and messenger substances are released that control essential metabolic and regenerative processes. Deep sleep is therefore our body's central recovery period, during which proteins, cells and tissues are repaired, detoxified and built up, the immune system is trained and energy reserves are renewed. And our brain is also active, as declarative memory, which is responsible for learning facts and memories, is especially formed during deep sleep.

      REM sleep phase

      Following deep sleep, we slide into the dream sleep phases, also known as REM phases. REM stands for "Rapid Eye Movement" because during these sleep periods, our brain processes and evaluates the experiences of the day and we move our eyes back and forth rapidly under our closed lids. For this to work, blood flow to the brain increases, blood pressure rises, and our heart rate and breathing also become more irregular. At the same time, we are in what is called sleep paralysis, in which the brain stem blocks the transmission of commands to our muscles to protect us from uncontrolled movements and injury during vivid dreaming. Accordingly, during REM sleep, important processing and learning takes place in the brain and procedural memory, which forms the basis for subconscious skills such as automated movement and motor learning, is formed.

      The importance of sleep cycles

      Schlafphasen/Wachphasen im Überblick

      During the night, we go through several sleep cycles. A cycle lasts approximately 90 to 110 minutes and consists of the fixed sequence of the five stages of sleep, although the ratio of sleep stages within a sleep cycle changes throughout the night. At the beginning of our sleep, we experience longer periods of deep sleep, as these are urgently needed to restore the energy reserves used up during the day. Towards the end of the night, we then spend more time in REM sleep, where the available energy can be used for important brain functions. For the recovery of body and brain, the first two sleep cycles, the so-called core sleep, are therefore particularly important and the most important restorative processes take place in our cells and nervous system. For an all-round restful awakening in the morning, however, it is important to go through about 4 to 7 sleep cycles and thus to sleep between 7 and 8 hours.

      Want to learn more?

      In our new podcast sleep SMART! we talk to our CEO and former sleep researcher Dr. Markus Dworak about sleep stages and learn from him more interesting and scientific information about how important our sleep cycles and the different sleep stages are for a restful night and healthy day! Listen in now ➨


      • Sleep consists of several sleep cycles that differ throughout the night and are divided into five sleep stages
      • The five stages of sleep are: Sleep onset phase, light sleep phase, deep sleep phase, REM sleep phase.
      • In deep sleep, energy reserves are replenished and the most important regeneration and reconstruction processes take place.
      • A restful sleep consists of 4 - 7 sleep cycles and therefore lasts at best between 7 and 8 hours per night.

      Best regards and see you soon!

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