FUNCTIONAL ADAPTATION OF THE CARDIOVASCULAR SYSTEM OF ATHLETES EXERCISING IN CYCLIC SPORTS

Peculiarities of functional adaptation of the cardiovascular system in athletes exercising in cyclic sports are described. The study involved 40 men aged 18 to 20. 20 people regularly practicing cyclic sports and having a degree of candidate or master of sports made up the main group. The control group comprised 20 boys not involved in professional sports and having no sports categories. All subjects belonged to the mainstream medical group and had no chronic diseases. The study of the physical performance and evaluation of the adaptive capacity of the cardiovascular system was conducted on hardware-software complex "Valenta". This technique allows conducting a complex test PWC170 with automatic control, real-time determination of elements of the QRS-complex and the calculation of its parameters for automatic control of the load device. Determination of lactate in venous blood was performed using the portable biochemical express analyzer "Accutrend Plus" before and after the PWC170 test. The results were processed by methods of variation statistics using Student's t-test. Organs and systems of the athlete undergo various morphological and functional reorganizations with increasing loads and degree of adaptation. In the process of sports training functional adaptive changes develop in the cardiovascular system which are supported by morphological restructuring ("structural trace") of the circulatory apparatus and some internal organs. This restructuring provides the cardiovascular system with high availability, which allows the athlete to endure intense and prolonged exercise. According to veloergometry athletes showed an increase in the index of inotropic reserve, while the index of chronotropic reserve decreases. Athletes showed a reduction in the total work and the ratio of spending of myocard reserves. At the same time, the index of double product did not differ for athletes and untrained persons. The study of blood lactate in both groups showed a significant increase after loads. However, in the control group it increases by 3.8 times, while in the main one - by only 1.8 times. No significant differences in blood lactate levels in both groups before the load is revealed. Thus, sportsmen training in cyclic sports have acardiovascular system which is much more efficient in providing for oxygen need, which is proved by the lower concentration of lactic acid and, consequently, they have a smaller degree of oxygen debt. However, this efficiency is not related to the magnitude of coronary blood flow, which is proved by the amount of the double product. The heart of trained individuals works more economically, which is proved by the amount of the chronotropic reserve, and the coefficient of the total spending of myocard reserves. At the same time athletes have more pronounced mobilization of the sympathetic component, which is proved by the increase in inotropic reserve.