Effects of hyperbaric oxygen on aerobic performance in a normobaric environment.

The purpose was to examine the acute effects of a hyperbaric oxygen (HBO2) treatment on a) recovery following prolonged exercise and b) aerobic performance in a trained population. Subjects were six male and six female, trained runners with mean Vo2max values of 64.6 +/- 5.6 and 51.9 +/- 6.6 ml x kg(-1) x min(-1), respectively. Subjects performed four exercise-HBO2 conditions in random order: a) control, b) exercise-no HBO2, c) no exercise-HBO2; and d) exercise-HBO2. Exercise was a 90-min run at 75-80% of Vo2max x HBO2 treatments consisted of breathing 95% O2 at 2.5 atm abs for 90 min. At the end of each condition, aerobic performance was assessed with a VO2max test and by the oxygen cost of running on a treadmill at three submaximal velocities. Recovery was not enhanced following a single HBO2 treatment at 2.5 atm abs for 90 min, nor did it alter submaximal or maximal running performance.