Effects of 100% oxygen on performance of professional soccer players.

Supplemental oxygen is currently widely utilized in conjunction with athletic competition. To assess the utility of this practice, 12 professional soccer players performed two bouts of exhaustive exercise separated by 5 minutes of rest ("recovery period"). During the recovery period, the subjects breathed either room air or 100% oxygen, assigned by randomized, double-blind design. The entire procedure was repeated on each subject using the opposite gas. The administration of enriched oxygen during the recovery period had no effect on plasma lactate levels or on performance during the second period of exercise. The subjects were unable to identify which gas they received. In conclusion, data from this study indicate that using 100% oxygen applied for short periods offers no advantage on recovery from exhaustive exercise or on subsequent exercise performance.