Sleep – What happens to body and brain?
Have you ever wondered what actually happens to us during sleep and which senses are active while we are dreaming? The key to the answer lies in the human sleep rhythm. During the course of the night, the organism goes through different sleep phases in which different processes in the body and brain are set in motion. We take a close look at the phenomenon of sleep for you!
- The phenomenon of sleep – what’s behind it?
- What happens during the individual sleep phases?
- Learning while you sleep - is there anything to it?
The phenomenon of sleep – what’s behind it?
While we are slumbering towards the new day at night, our body does amazing things. During sleep, for example, the information of the day is processed, new learning experiences are stored and on the cellular level numerous repairs take place that strengthen the immune system and protect us from disease. With this in mind, it is not surprising that healthy sleep is so important to our well-being and health! The prerequisite for being able to start the next morning full of energy and rested is an undisturbed cycle of the individual stages of sleeping. Human sleep is usually divided into four to five sleep phases that are repeated up to seven times during the night:
- Fall asleep
- Light sleep
- Deep sleep
- ream sleep (REM phase)
- Wake-up phase
What happens during the individual sleep phases?
IIn every phase of sleep, certain processes take place in the body that contribute to a restful night and let you to start the day fit the next morning.
The falling asleep phase
When it gets dark in the evening, the pineal gland stimulates the production of the "sleep hormone" melatonin. The increasing concentration of melatonin in the blood signals the body to shut down and prepare for sleep. As a result, blood pressure and heart rate decrease, breathing becomes shallower, and body temperature drops. Incidentally, the time it takes to fall asleep varies from person to person - while some people are in the realm of dreams after just five minutes, others need up to half an hour.
The light sleep phase
With the transition to light sleep studies (called non-REM phases I and II in sleep medicine) the human body prepares for recovery. The muscles continue to relax as the brain begins to sort and store the information of the day. This means we are receptive the next morning when the brain is exposed to new stimuli. Good to know: We spend almost half of our total sleep time in light sleep. 
The deep sleep phase
In the deep sleep phase it is hardest to wake up the sleeper, because the body and brain work at full speed on cell repair and memory formation. Since the most important regeneration processes take place on the deep sleep phase, this sleep phase is particularly important for a restful night's sleep. With each new sleep cycle, the length of deep sleep is reduced a little.
The dream sleep phase (REM phase)
Rapid eye movements behind the lids, the so-called Rapid Eye Movements (REM), are characteristic of dream sleep. In this state we dream intensely - at the same time the muscles freeze, so that dreamed movements cannot be implemented and the information processing in the brain runs as undisturbed as possible. The proportion of REM sleep is around 20% of the total sleep duration and increases from the second half of the night.
The wake-up phase
In the last stage of sleep, the body slowly reboots all systems and prepares for daybreak: We wake up. Body temperature and heart rate rise, breathing accelerates and the stomach is supplied with more blood - this is also the reason why many people already have a great appetite immediately after sleep and look forward to a hearty breakfast.
Learning while you sleep - is there anything to it?
Learning while you sleep? What sounds like pure wishful thinking really works to a certain extent! Especially in the deep sleep phase, strong brain activity can be observed in the areas linked to long-term memory - you can take advantage of this fact! It is not enough to take a language course shortly before falling asleep and to absorb all the vocabulary while sleeping, but human memory is formed and consolidated, especially overnight. What has been learned and experienced is now transferred to the brain: Therefore, the actual learning process is only completed after a complete sleep cycle. Good, high-quality sleep thus helps to store new information or movement sequences in long-term memory and to be well prepared for the next examination phase.