ADAPTATION TO INTERVAL HYPOXIAHYPEROXIA IMPROVES EXERCISE TOLERANCE IN PROFESSIONAL ATHLETES: EXPERIMENTAL SUBSTANTIATION AND APPLIED APPROBATION

Abstract

A theoretical substantiation and experimental testing of combined adaptation to changing oxygen levels in the enhancement of tolerance to physical loads and pilot study on the protective effects of a novel strategy for adaptation to interval hypoxia-hyperoxia aimed at eliminating the overtraining syndrome in professional athletes, have been carried out. Methods On the experimental step, adaptation of male Wistar rats was performed in 2 modes: 1) hypoxia-normoxia (H/N): 2) a new model - hypoxia-hyperoxia (H/H), 1h daily for 15 days. Acute physical load (APL) consisted in swimming (21oC) to exhaustion. Intensity of free radical oxidation was estimated by the rate of accumulation of lipid peroxidation products in the course of induction in the Fe2++ ascorbate system in vitro. Activities of antioxidant enzymes were measured by spectrophotometria, levels of inducible HSP72, HSP32 and constituitive HSC73 were measured by Western blot analysis with monoclonal antibodies. On the pilot study 15 male and female middle-distance runners with overtraining syndrome wereexposed to interval hypoxia-hyperoxia training (IHHT) sessions. Working capacity (PWC170), hypoxic tolerance, haematological parameters and heart rate variability (HRV) analysis were determined before and 3 days after IHHT sessions. Results In experiments combination of adaptation to physical exercise with adaptation to hypoxia-hyperoxia improves tolerance under conditions of APL: short-term adaptation to physical exercise compensates for stress, but not for the hypoxic component of APL, while physical training combined with adaptation to hypoxia-hyperoxia fully compensates for both components. In 15 young professional athletes with overtraining syndrome combination of IHHT with low-intensity exercise restores the autonomic balance and physical capacity (significant elevation of PWC170 index, maximal oxygen consumption VO2max, and VO2max/kg). Conclusion Adaptation to interval hypoxia-hyperoxia provides optimization of the hypoxic and stress componentsinexercise tolerance systemic response which is revealed in experimental studies and supported by the data of young athletes with overtraining syndrome rehabilitation.