Recovery-Targeted Supplemental Oxygen Enhances Performance and Attenuates Perceived Fatigue During Subsequent High-Intensity Swimming

High-intensity aquatic sports require athletes to repeatedly produce near-maximal efforts under conditions of constrained ventilation and limited recovery between bouts, placing substantial importance on recovery efficiency. While supplemental oxygen has been proposed as a recovery-targeted strategy to support repeated high-intensity performance, its acute effects in aquatic athletes remain poorly characterized. The purpose of this study was to examine whether brief inhalation of supplemental oxygen during recovery following a maximal swim effort influences subsequent swimming performance and perceived exertion in trained aquatic athletes. Eighteen collegiate-aged male aquatic athletes completed a randomized, placebo-controlled, within-subject crossover protocol. Each condition consisted of a maximal 100-yard (91.44 m) swim followed by a standardized recovery period that included a five second inhalation of either 98% supplemental oxygen or ambient air delivered via an identical portable device, prior to a maximal 50-yard (45.72 m) freestyle sprint. Sprint performance was significantly faster following oxygen-assisted recovery compared with placebo, and perceived exertion was significantly reduced at the post-exercise time point, with no differences observed prior to exercise or mid-protocol. These findings suggest that brief, recovery-targeted hyperoxia may enhance repeated high-intensity swimming performance while attenuating post-exercise perceived exertion in trained aquatic athletes.