Ingestion of oxygenated water enhances lactate clearance kinetics in trained runners

Background: Drinks with higher dissolved oxygen concentrations have in recent times gained popularity as a potential ergogenic aid, despite a lack of evidence regarding their efficacy. The aim of this study was to assess effects of ingestion of an oxygen supplement (OS) on exercise performance and post-exercise recovery in a group of trained runners. 3 Methods: Trained male runners (n = 25, mean +/- SD; age 23 +/- 6 years, mass 70 +/- 9 kg, BMI 21.9 +/- 2.7 kg.m(-2) VO(2)max 64 +/- 6mL.kg(-1).min(-1)), completed a randomised double blinded, crossover study to assess the effect of ingestion of OS solution on exercise performance and recovery. Trials consisted of a 30min rest period, 5min warm-up, a 5000m treadmill time-trial, and a 30min passive recovery. Participants ingested 6x15mL of either OS or a taste matched placebo during the trials (3 during the rest phase, 1 during exercise and 2 during the recovery). Muscle tissue O-2 saturation was measured via near infrared spectroscopy. Blood lactate concentrations were measured prior to, mid-way and directly after the finish of the 5000m time trials and every 3-min during the post-exercise recovery. Results: Ingestion of OS did not improve exercise performance. No significant differences were observed for muscle tissue O-2 saturation at any time-points. However, lactate clearance was significantly improved during recovery in the OS trials. Both AUC (109 +/- 32 vs. 123 +/- 38 mmol. min, P < 0.05, d = 0.40) and lactate half-life (lambda) (1127 +/- 272 vs. 1223 +/- 334 s, P < 0.05, d = 0.32) were significantly reduced. Conclusions: Despite no evidence of improved exercise performance, ingestion of OS did enhance post-exercise recovery via increased lactate clearance.