Arterial compliance in divers exposed to repeated hyperoxia using rebreather equipment

Acute hyperoxic exposure is known to modify cardiovascular parameters like a decrease in cardiac output, arterial vasoconstriction, and autonomic nervous system changes. We hypothesized that repeated hyperbaric hyperoxic exposures, as experienced by military oxygen divers, lead to long-term arterial alterations. Arterial blood pressure measurements and pulse wave velocity (PWV) recordings were performed during basal conditions in 15 elite military oxygen divers, and compared to 15 non-diver controls. The two groups were matched appropriately for physical characteristics (age: 35 +/- 5 yr, weight: 77 +/- 8 kg, height: 177 +/- 6 cm, body mass index: 24.6 +/- 2.0 kg x m(-2)), and aerobic capacity (VO2max : 52 +/- 7 ml x min(-1) x kg(-1)). No significant difference was found in systolic blood pressure (120 +/- 11 mmHg), diastolic blood pressure (70 +/- 8 mmHg), or pulse pressure (50 +/- 7 mmHg). Furthermore, there was no significant difference in the carotid-femoral PWV (6.7 +/- 0.9 m x s(-1)), the carotid-radial PWV (8.7 +/- 1.7 m x s(-1)), or the carotid-pedal PWV (8.1 +/- 1.1 m x s(-1)) between divers and controls. No difference in arterial compliance was observed in physically well-trained military oxygen divers in comparison with matched controls.