Adaptive reactions of the cardiovascular system of girls of different stade of puberty on physical activityduring the academic year.

Controlled physical activity of moderate power working capacity (50% of PWC170) causes a marked change in the cardiovascular system (stroke volume and minute blood volume, heart rate) in 11-16-year-old girls at different stages of puberty (stages 1-5). The reaction of urgent adaptation of girls' cardiovascular system to physical activity during the pubertal period depends on the level of their sexual maturity. The pronounced chronotropic effect of cardiovascular system is revealed in girls at the 1st and the 2nd stages of puberty in response to a functional test, during the academic year. The inotropic effect is more pronounced in girls at the 3rd -5th stages. There are moderate changes in the studied parameters in response to a functional test and their relatively rapid recovery to the background level in girls at the 1st and the 2nd stages of puberty. A long period of wave-like recovery of the studied parameters to the baseline level, with the appearance of "negative phase" of the h