Effects of normobaric hypoxia on upper body critical power and anaerobic working capacity

Purpose To evaluate the effects of moderate normobaric hypoxia on the parameters of the work-time relationship in the upper body. Methods Twenty-one recreationally active men completed a graded exercise test in both normobaric hypoxia (H) and normoxia (N) to exhaustion on an arm ergometer to determine V̇O₂peak and peak power output (PPO). Each participant completed four constant work-rate (CWR) arm-cranking tests at 90–120% PPO in both environmental conditions. Linear regression was used to estimate critical power (CP) and anaerobic working capacity (AWC) via work-time relationship during the CWR tests. Results H significantly reduced V̇O₂peak (N: 2.34 ± 0.34 L vs. H: 2.27 ± 0.34 L, p = 0.041), PPO (N: 125.29 ± 17.98 W vs. H: 121.11 ± 17.98 W, p = 0.001), and CP (N: 90.22 ± 12.88 W vs. H: 85.26 ± 9.64 W, p = 0.042), but had no effect on AWC (N: 9.16 ± 2.81 kJ vs. H: 8.75 ± 3.23 kJ, p = 0.600). Discussion Moderate normobaric hypoxia appears to reduce CP in the upper body but has a variable effect on AWC.