Fig. 1.

Detailed hyperbaric exposure timeline. Hyperbaric exposure is shown in atmospheres absolute pressure (ATA) units. Trial 1 (normoxia) was performed at 1 ATA while breathing normoxic gas (air; 21% O₂). Trials 2 and 3 took place at 2.82 ATA while breathing 7.4% and 100% O₂, respectively. Breathing 7.4% O₂ at a depth of 2.8 ATA is the equivalent to breathing room air at sea level and served as a “pressure control” trial. Breathing 100% O₂ at a depth of 2.82 ATA served as the hyperoxic trial. Each trial consisted of a Po₂ normalization period (5 min), rest (2 min), and exercise (4 min). fsw, feet of sea water.