engleski

Is recovery in hyperoxia after high intensity training in hypoxia an added value

Methods to improve athletic performance include the hypoxic and recently also the hyperoxic training. This study hypothesized that a combination of high intensity interval hypoxic training (HIIT) followed by a recovery in hyperoxia improves the aerobic endurance and oxygen transport parameters better than recovery in normoxia. Forty-nine fit men, 18-20y, were randomly divided into: Hypo+Hyper group (N=16) performing HIIT in hypoxia with 15min recovery in hyperoxia at FiO2=0.40 ; Hypo group (N=16) HIIT in hypoxia/recovery in normoxia and Control group (N=17) performing everyday activities. The intervention lasted 4 weeks ; 3x/week. Each week, the intensity was increased by 5%. HIIT in hypoxia exercise protocol consisted of six bouts of 1min at 80-95% of HRmax, each week at higher rate, respectively, followed by 2min at 60% of HRmax. Pre- and postintervention the blood was analyzed related to oxygen transport parameters and an all- out-treadmill test carried out. At maximal exertion Hypo-Hyper group had a larger increase in maximal oxygen uptake-VO2max, (pre- 49.34 and post- 50, 79ml/kgmin-1) as opposed to controls (pre- 48.04 and post- 46, 71ml/kgmin-1 ; p<0.05) as expected, and somewhat larger than only Hypo group (pre- 46.89 post- 47, 56 ml/kg min-1, p=0.176). There was also larger difference in maximal speed reached in Hypo-Hyper group vs both groups (p<0.01). Significant changes at anaerobic threshold involved only increase in oxygen uptake values at threshold in Hypo-Hyper group. Changes in blood oxygen transport parameters occurred as hemoglobin mass increase the most in Hypo+Hyper group (+11.8 in Hyper+Hypo vs +0.8 in Hypo and -0.7 g/L in Controls ; p<0.05 and p<0.01 respectively). Slight hematocrit changes were also noted. The study innovation lays in design, as both methods, hyperoxia and hypoxia training were usually studied separately. It seems that the optimal training for short periods might be HIIT with hyperoxia recovery but further studies, involving better understanding of underlying mechanisms, should follow.

hypoxia ; hyperoxia ; HIIT

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