A restful sleep feels like magic: We wake up feeling fresh, focused – simply like new. But what exactly happens during the night when our body seems to be “doing nothing”? The answer lies in a highly complex interplay of biological processes that take place in so-called sleep phases.
Sleep is not a uniform state, but takes place in several repeating phases. These so-called sleep cycles consist of different stages that the body goes through several times during the night – usually around 4 to 6 cycles, each lasting around 90 minutes.
An overview of the most important phases::
1. Sleep phase: The transition
In the sleep phase, the body and mind begin to calm down. Muscle activity decreases, pulse and breathing rate slow down. This phase is short and light – a small external stimulus can easily wake us up again.
2. Light sleep phase: the body switches
Here sleep becomes somewhat deeper. Consciousness is switched off, but the body is still in a state of heightened sensitivity to sounds and movements. We spend around 50% of our total sleep time in this phase.
3. Deep sleep phase: regeneration begins
Deep sleep is particularly valuable for the body. Important physical recovery processes take place here. The focus is on cell repair, growth and energy production. The immune system can also be supported in a natural way during this phase.
4. REM sleep: the mind becomes active
REM stands for “Rapid Eye Movement” – named after the rapid eye movements during this phase. The body is outwardly paralyzed, but the brain is working at full speed. During this phase, we dream intensely and our brain processes emotions, impressions and information from the day. REM sleep is therefore considered crucial for mental balance and memory formation.
Sleep cycles during the night
At the beginning of the night, deep sleep predominates – this is where intensive physical regeneration takes place. In the second half of the night, the proportion of REM sleep increases significantly – mental recovery becomes more important. This explains why a night that is too short or frequently interrupted does not give the body enough time to go through all phases completely. High-quality sleep therefore depends not only on the duration, but also on how “complete” the cycles can be.
Sleep is not a passive break – it is an active regeneration process that takes place in finely tuned phases. Each phase fulfills an important function for body and mind. If you know the processes involved, you will better understand why regular, high-quality sleep is so essential – not just for energy the next day, but for long-term well-being.
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