Effect of hyperbaric oxygen on oxygen uptake and measurements in the blood and tissues in a normobaric environment

Objective: To examine venous partial pressure of oxygen (PvO(2)), transcutaneous oxygen tension (tcPO(2)), and VO(2)MAX in a normobaric environment after a single hyperbaric oxygen (HBO2) treatment. Methods: This was a prospective study of conditions after the intervention compared with baseline. The participants were 10 moderately trained (VO(2)MAX = 57.6 ml/kg/min) men. Two HBO2 treatments consisting of breathing 95% oxygen at 2.5 atmospheres absolute (ATA) for 90 minutes were administered on non-consecutive days. Baseline testing included measures of VO(2)MAX, tcPO(2), and anthropometry. At 6.0 (1.0) minutes after the first HBO2 treatment, a VO(2)MAX test was performed. After the second HBO2 treatment, leg and chest tcPO(2) and PvO(2) were monitored for 60 minutes. Results: VO(2)MAX, running time, and peak blood lactate were not altered after the HBO2 treatment. Leg tcPO(2) was lower (p = 0.003) and chest tcPO(2) was unchanged after the HBO2 treatment compared with baseline values. PvO(2) was significantly (p < 0.001) lower in the first three minutes after treatment than subsequent values, but no other differences were found. Conclusions: A single HBO2 treatment at 2.5 ATA for 90 minutes does not raise PvO(2), tcPO(2),(,) or VO(2)MAX in a normobaric, normoxic environment.