During deep sleep, important processes occur: the accumulation of necessary substances for the full functioning of the body, the synthesis of amino acids, regeneration processes, and the synthesis of somatotropic hormone (growth hormone).
What is deep sleep
Deep sleep is the slowest phase of human sleep. It is during deep sleep that the body is fully restored, the psyche is put in order, the brain is “cleansed” of unnecessary information received during wakefulness and “puts into place” everything important and necessary.
All stages of sleep are important, but deep sleep is responsible for making you feel restored when you wake up.
When a person falls into deep sleep
During the night, each sleep cycle is different, with the deepest sleep occurring in the first half of the night and the deepest REM sleep occurring in the second half.
Therefore, by the time you get to early morning, you'll mostly be alternating between NREM sleep and REM sleep.
How long should deep sleep last
In childhood and young adulthood, deep sleep accounts for 15–25% of total sleep time.
In older people, it can be reduced to a few percent or even drop to zero.
Sometimes the indicator, on the contrary, can increase.
For example, if a person did not get enough sleep the previous night.
How to tell if you are in deep sleep
During REM sleep, a person's eyeballs move, breathing and heart rate increase.
Nevertheless, in the slow state, he looks more like a sleeper: he lies calmly on the bed, breathes regularly and deeply, and his heart beats slower.
