Normal (physiological) sleep consists of two qualitatively different phases – slow and fast sleep. Slow sleep is characterized by a decrease in all the functions of the human body, the absence of dreams and rapid eye movements. However, in a state of slow deep sleep, a person can quickly wake up when exposed to stimuli important to him. Periodically, every 80-90 minutes, slow sleep is replaced by fast sleep, which is approximately 20% of the total sleep time.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.