A healthy, restful sleep is very important for our body. When you are lacking sleep, symptoms like lack of concentration, tiredness and fatigue might arise. Sleep consists of five different phases of sleep that alternate during the night. Besides the phase of falling asleep there are the phases of REM-sleep and deep sleep. During the last mentioned phases, our body cells are working at full blast. Cell repair takes places, growth hormones are released, impressions and learning contents are processed and saved.
Different phases of sleep
During night, the five sleeping stages repeat up to six times. The phases of falling asleep resp. of light sleep are phase one and two. There are two phases of deep sleep that form stage three and four. REM-sleep is the fifth phase. The longest phase of deep sleep is the first one; it takes about one hour. In the course of the night the duration of phases of deep sleep decrease and the duration of REM-sleep-phases increase.
Function and task of deep sleep
Deep sleep is the most relaxing one for our body. Here, the cortisol level is the lowest.
During deep sleep, muscle tension, body temperature and blood pressure decrease. The circulatory slows down. Also, growth hormones are released. These hormones stimulate cell repair and strengthen the immune system. The regulation of metabolism takes place. Furthermore, learning contents and impressions are solidified during sleep. A transfer from short-term memory into long-term memory takes place.
Consequences of missing deep sleep resp. of lack of sleep
Due to a natural rhythm of rest and activity vital body functions like breathing, heart frequency, muscle tension and body temperature remain constant. Missing or too short deep sleep unbalances these important body functions. Lack of sleep leads to an increased release of cortisol; permanent stress might arise. This in turn might negatively influence metabolism. Furthermore, people with a shortened or missing deep sleep have a decreased learning capacity and retentiveness.