Maximal Oxygen Uptake Is Achieved in Hypoxia but Not Normoxia during an Exhaustive Severe Intensity Run (original) (raw)

Highly aerobically trained individuals are unable to achieve maximal oxygen uptake (VO 2max) during exhaustive running lasting ∼2 min, insteadVO 2 plateaus belowVO 2max after ∼1 min. Hypoxia offers the opportunity to study the (VO 2) response to an exhaustive run relative to a hypoxia induced reduction inVO 2max. The aim of this study was to explore whether there is a difference in the percentage ofVO 2max achieved (during a 2 min exhaustive run) in normoxia and hypoxia. Fourteen competitive middle distance runners (normoxicVO 2max 67.0 ± 5.2 ml.kg −1 .min −1) completed exhaustive treadmill ramp tests and constant work rate (CWR) tests in normoxia and hypoxia (F i O 2 0.13). TheVO 2 data from the CWR tests were modeled using a single exponential function. End exercise normoxic CWRVO 2 was less than normoxicVO 2max (86 ± 6% ramp, P < 0.001). During the hypoxic CWR test, hypoxicVO 2max was achieved (102 ± 8% ramp, P = 0.490). The phase II time constant was greater in hypoxia (12.7 ± 2.8 s) relative to normoxia (10.4 ± 2.6 s) (P = 0.029). The results demonstrate that highly aerobically trained individuals cannot achieveVO 2max during exhaustive severe intensity treadmill running in normoxia, but can achieve the lowerVO 2max in hypoxia despite a slightly slowerVO 2 response.