Hormonal, metabolic, and angiogenic responses to all-out sprint interval exercise under systemic hyperoxia

Objective: Hyperoxic gas inhalation during exercise may negatively affect all-out sprint interval exercise (SIE)-induced hormonal, metabolic, and angiogenic responses. We investigated the effects of acute all-out SIE under systemic hyperoxia on hormonal, metabolic, and angiogenic responses. Design: This was a randomised-crossover trial. Ten healthy males (mean +/- standard error of age = 23.1 +/- 0.9 years; height = 171.0 +/- 1.6 cm; body mass = 66.2 +/- 2.0 kg; body mass index = 22.6 +/- 0.5 kg/m(2)) completed the following two experimental regimens: 1) SIE under normoxia and 2) SIE under systemic hyperoxia (FiO(2) = 60%). The subjects performed four bouts of 30-s maximal cycling efforts with 4 min recovery between efforts. The circulating levels of hormonal (growth hormone, epinephrine, and norepinephrine), metabolic (glucose, free fatty acid, and lactate), and angiogenic (vascular endothelial growth factor, matrix metalloproteinase-2 and -9, and endostatin) markers were measured before and at 0 (immediately after the regimen), 30, and 120 min after both regimens. Results: In response to both SIE regimens, the peak and mean power outputs gradually decreased over the intermittent exercise session compared with those in the first bout (p < 0.01) with no significant differences between the regimens. Both regimens significantly increased the circulating concentrations of all hormonal, metabolic, and angiogenic markers (p < 0.01). However, there were no significant differences in the levels of these markers in response to the two regimens at any time point (p > 0.05). Conclusion: These findings suggest that acute systemic hypemxia does not influence the hormonal, metabolic, and angiogenic responses to all-out SIE.