Sleep is a physiological state in which a person relaxes and sees dreams. It is characterized by decreased reaction and muscle relaxation.
The phenomenon of sleep haunts people for many millennia. What is sleep? Why during sleep do we see images, experience various situations, mentally perform some actions?
Aristotle believed that a sleeping person is halfway to death. Ancient thinkers explored dreams as a parallel reality into which our soul temporarily moves. It was only after Darwin voiced his revolutionary theory that it became clear that dreams, which are a subjective reflection of reality, are generated by the human brain.
As a basic theory, it was suggested that during sleep, the brain rests and recovers in order not to wear out prematurely. Indeed, sleep is more important to humans than food and water. In ancient China, one of the most cruel types of executions was depriving a person of the opportunity to sleep. Without sleep, such people lived no more than 10 days, although a person can do without food for up to two months.
In the 20th century, scientists began to study the phenomenon of sleep closely. And it turned out that the theory of rest is not entirely true. An interesting fact is that during sleep, the activity of the brain decreases by only 15-20 percent compared to the state of wakefulness. As for physical rest for the muscles of the body, then for this it is enough just to lie down, it is not necessary to sleep. So why do we need to spend a third of the day in a state remotely similar to death? Indeed, in a state of sleep it is impossible to react to danger, which in the process of evolution was one of the main conditions for survival.
During the slow phase of sleep, metabolism slows down, muscles relax, and body temperature drops. REM sleep occurs 1.5-2 hours after falling asleep. We see dreams at this very time when processes occur in the body that contribute to the restoration of the nervous system.
There are cases in history that confirm that the thought process is not interrupted even during sleep. Often a sleeping person finds a solution to a problem that has haunted him all day. Chemists dream of formulas, over which they struggle unsuccessfully in the daylight, musicians compose melodies, writers see the plots of books.
In order to unravel the phenomenon of sleep, numerous scientific studies are carried out. It has already been established that during sleep a person's motor skills (for example, the skill of playing the piano) are fixed.
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As for dreams, everything is more complicated here. Calm, positive dreams cheer you up. Wise dreams push you to make the right decisions. But what about the nightmares? Why are they needed? Researchers believe that sleep is a kind of exercise. Dreams help the nervous system develop, which explains the fact that newborns also have dreams. After analyzing the information that was received during the day, the brain during sleep simulates the situation that may arise in reality. Dreams are designed to help solve problems that have to be solved every day. Thus, certain skills and reactions to external stimuli are formed. For example, having escaped from a monster in a nightmare, it will be easier for us to escape from a mad dog in reality. The brain will remember what needs to be done in this situation, since it will not be new to it.