Oxidative stress (OS) is common for intensive physical trainings of sportsman. It is also a well-known pathophysiological factor of fatigue formation and overstrains in athletes, which can create prerequisites for deterioration of athletes’ health and quality of life. Sometimes it can even cause their exclusion from the training process. Currently, an assessment of the intensity of lipid peroxidation (LPO) processes and the activity of the body antioxidant system (AOS), as the opposite aspects of OS, is widely used in the practice of the laboratory control for work capacity stimulation and the development of fatigue and overstrain in athletes. Intensive physical trainings tend to enhance LPO processes and contribute to accumulation of intermediate and end products of these processes in blood that limit physical work capacity. Laboratory diagnostics of LPO/AOS system condition represents a complex multifaceted procedure. Therefore unified criteria for disorder of the content and activity of the system components are practically unavailable in this case. They depend on the laboratory equipment and the methodology. While the determination of LPO products is quite frequently used in the practice of the laboratory control, the condition of AOS is evaluated less often due to methodological difficulties, which further complicates the validated assessment of OS expressiveness and prescription of antioxidant preparations. However, until now antioxidants have been used schematically in sport in general and in elite sport in particular, depending on the stage/period of annual preparation macrocycle and sports’ peculiarities. First of all, it refers to cyclic sports events, in which the activity of free radical oxidation processes is maximal. In this case it is recommended to use natural and synthetic antioxidants at every stage of preparation, which is far from being always sound from the athletes’ individual responses towards their trainings and specifics of the energy supply mechanisms in different sports events. Nowadays one of the standardized criteria for correlation of the LPO and antioxidant defense processes in athletes is the definition of the so-called, prooxidant-antioxidant coefficient (Cpa), suggested by the authors. It is calculated by ratio of malondialdehyde (MDA), one of the end products of LPO, and reduced glutathione (GSH), one of the major natural antioxidant, contents in erythrocyte cellular membranes. Cpa value above 2.0-2.5 c.u. indicates the activation of LPO processes during the development of fatigue and overstrain due to damage of biological membrane lipid layer, and justifies the necessity of using antioxidant preparations as one of the constituents of the scheme of training activity pharmacological support. In the course of studies 89 top level male athletes (Masters of sport of Ukraine, International class masters) have been examined at the stage of direct preparation for the competitions. In particular 65 representatives of cyclic sports events including 38 middle distance runners and 27 kayakers and canoeists, and 24 athletes of strength sports events (weightlifters). Changes of antioxidant enzyme activity were differently-directed in the examined groups of athletes: as compared to the index of the control group of healthy non-athletes, the activity of superoxide dismutase in the group of kayakers and canoeists, that of middle distance runners and that of weightlifters was significantly reduced by 20.3 %, 29.5 % and 16,3 %, respectively. At the same time, the activity of erythrocyte cataloes in the group of rowers was increased by 34.1 %, 21.3 % and 8.7 % as compared to data of the control group, the group of runners and the group of weightlifters, respectively. The above results, however, do not prevent a moderate decrease of the importance of “AOS factor” as an integral index of the body antioxidant defense state. In accordance to these results, both groups of athletes of cyclic sports events needed to use antioxidant medications, unlike the representatives of strength sports events with preferentially anaerobic glycolytic mechanism of energy supply (weightlifters). Therefore, the authors assume that schematic, based on the results of individual usage of antioxidants as a part of sports training pharmacological support, may have an expected positive impact on work capacity and also exert a negative influence upon several processes (erythropoiesis, angiogenesis, respiratory chain activity) and functional systems of regulation (kallikrein-kinin, renin-angiotensin, energy formation) that depend on prooxidant-antioxidant balance in the body of athletes.
Keywords: elite sport, energy supply mechanism, oxidative stress, pharmacological support
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