Sleep is a periodically occurring physiological state in humans and animals, characterized by an almost complete lack of response to external stimuli, and a weakening of the activity of a number of physiological processes. Sleep is rest. The duration of a teenager’s sleep should be 8.5–9 hours, that of an adult – about 8 hours. Sleep returns the tired body vigor and strength for new actions that make up life. Constant lack of sleep and sleep disturbance contribute to the accumulation of fatigue and provoke various negative deviations in the state of health.
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.