Assessment of the oxidative-antioxidant status and aerobic performance of elite skiers-racers in the dynamics of training cycle at moderate altitude

Adaptation to hypoxia is an integral part of elite athletes training at various stages of the training and competition season. One of the key issues in the use of additional hypoxic stimulation methods is the potential risk of oxidative stress development and dangerous shifts in oxidative-antioxidant status (OAS). Objective: to identify the impact of altitude training and the subsequent period of reacclimatization on exercise performance, aerobic efficiency and oxidative-antioxidant balance of elite skiers-racers. Materials and Methods: The study involved 10 highly qualified athletes who underwent a comprehensive examination three times at different stages of training camps: initially, after 3-week camps in the natural midlands and after a 2-week camp on the plain. Each comprehensive examination included exercise treadmill testing under normoxia and in moderate hypoxia with determination of spiroergometric indicators, measurement of hemoglobin, hematocrit, total hemoglobin mass, as well as OAS parameters. Results: Endurance training at moderate altitude led to significant increase in the total hemoglobin mass and with the delay of 16-18 days of reacclimatization – in performance indicators (VO 2 max and VO 2 /AT), tested both in normoxia and hypoxia. No significant average group changes in the oxidativeantioxidant status in the dynamics of professional skiers' 3 weeks acclimatization period were revealed. In the analysis of individual indices dynamics it was noted that in the majority of athletes the values of oxidative stress indicator (d-ROM) did not exceed the limits of normative data, and the index of total antioxidant blood potential were in the zone of slightly increased values at all stages of testing. As a result, the values of the OAS integral index of athletes were in the border zone, with several elevated values. At the same time, the level of overall activation of the pro-antioxidant system correlated with the increase in aerobic capacity of athletes. Conclusions: The OSA parameters tested using the FRAS-4 method make it possible to evaluate the dynamics of OSA in athletes training for endurance at moderate altitude.