Wakefulness and sleep are two physiological states of human activity that are caused by the activity of certain centers of the brain, in particular, the hypothalamus and subthalamus , as well as the areas of the blue spot and the suture nucleus located in the upper part of the brain stem. Both of these periods are cyclical in structure and are subject to the daily rhythms of the human body.
The rhythm of the inner clock
The mechanisms of wakefulness and sleep are still being studied, and there are at least several theories of how our internal clocks work. Being in a state of wakefulness, we consciously react to any stimuli, fully aware of our connection with the outside world, our brain activity is in an active phase and almost all life processes occurring in our body are aimed at absorbing and rational spending energy resources received from the outside in the form of food and water. In general, the psychophysiology of sleep and wakefulness is due to the regulation of various systemic structures of the brain, which, in particular, contributes to the accumulation of information received when we are in a state of activity and its more detailed assimilation and distribution to memory departments during sleep.
Five stages of sleep
The state of sleep is characterized by a lack of activity directed to the outside world and is conditionally divided into five stages, each of which lasts about 90 minutes.
- The first two of them are stages of light or shallow sleep, during which breathing and pulse rate slow down, however, during this period we can wake up even from the slightest touch.
- Then the third and fourth phases of deep sleep come, during which there is an even greater slowdown in the heartbeat and a complete lack of response to external stimuli. It is already much more difficult to wake up a person who is in the deep sleep stage.
- The fifth and final phase of sleep in medicine is called REM ( Rapid Eye Movement ). At this stage of sleep, breathing and heartbeat become more frequent, the eyeballs move under the closed eyelids, and all this happens under the influence of dreams that a person sees. Experts in the field of somnology and neurology argue that absolutely everyone dreams of dreams, just not all people remember them.
At the moment of falling asleep, as well as at the end of the deep phase of sleep, we enter the so-called borderline state between sleep and wakefulness. During this period, the connection of consciousness with the surrounding
reality, in principle, is present, but we do not fully associate ourselves with it.
Sleep and wakefulness disorders can be caused by various psychophysiological factors, such as uneven shift work, stress , change of time zones during air travel, etc. But the reasons for the disordered rhythm of activity – rest can also lie in certain diseases, in particular, narcolepsy or hypersomnia . In any case, for any more or less pronounced violations of the cyclicity of the states of wakefulness and sleep, it is advisable to consult a specialist.