Sleep is very important for the human body as it is needed for rest and recovery. There is no factor that has a greater influence on our well-being and our health than sleep. What exactly is sleep though?
Sleep is a very complex biological process in the body, which is controlled by the nervous system. Sleep is divided into two basic stages, where the central nervous system and various bodily functions are correspondingly active or less active, in order to enable rest and recovery in sleep.
1. Orthodox sleep or non-REM sleep - this essentially serves bodily recovery.
2. Paradoxical sleep (REM sleep) - in this phase, mental processing and dreams occur.
The first phase of sleep after falling asleep is orthodox sleep. The first phase of deep sleep takes approximately one hour, and after that the orthodox and the paradoxical sleep alternate. The need for sleep varies individually and is dependent on age. A baby sleeps about 16 hours per day, with almost 50% being REM sleep. In adults, the sleep duration is approximately 6-8 hours, with the proportion of REM sleep about 20%. As age goes on, the average sleep duration decreases further, with the proportion of REM sleep going down to 13%.
Each phase is important for sleep’s powers of recovery. Essential body processes such as the blood pressure, digestive activity and muscle tension change at night, depending on what stage the sleeper is in. You are temporarily shut down in some ways, as the blood pressure drops in deep sleep, and in other ways are stimulated, such as with certain metabolic processes. If your sleep gets interrupted a few times and you have to get up, the blood pressure rises again, for example.
Sleep and the immune system
During sleep, the immune system of people works at full blast. It is a time when especially large amounts of immune-active substances are secreted by the human body that have the task of boosting the immune system. Infections or similar things can therefore be repelled by the body without having to lead to illness. When it comes to illness though, the body stimulates sleep in most cases. Ill people are often tired. This increased need for sleep is made to give the body more time to regenerate. Studies have found that after six days of continuous sleep deprivation, the defensive power of the immune system is reduced.
Sleep and learning
Sleep is important not only to become physically fit, but plays a particularly important role for mental ‘fitness’. Sleep is important for improving our brain - in the truest sense of the word. In deep sleep, lots of information is transferred from people’s short-term memory to their long-term memory. This is necessary as people are constantly confronted in their waking hours by stimuli and information that needs to be processed. To ensure this processing works, space must be made in the short-term memory of the brain by transferring the information to the long-term memory. Sleep can therefore be seen as an information processor.