The Effects of Oxygen-Argon Gaseous Mixtures on Humans Under Long-Term Hyperbaric Condition

The goal of the present investigation was to estimate the human performance and adaptation of physiological systems during long-term exposure in argon-nitrogen-oxygen atmosphere. Four male volunteers participated in simulated diving to 10 m performed in the diving complex –GVK-250—. The subjects were exposed during 7 d to the following gas mixture (in partial pressures): oxygen - 0.2±0.005 kg/cm2, nitrogen - 0.8±0.01 kg/cm2 and argon - 1.0±0.01 kg/cm2. The volunteers performed physical and mental work in order to study mechanisms of cardiovascular, respiratory and nervous systems regulation under physical activity. We found no modifications of normal physiological characteristics of central nervous, cardiovascular, respiratory systems’ tests and in results of urine biochemical tests. Blood biochemical measurements did not show significant differences from control levels except shifts in lipid metabolism which are often observed during long-term simulated deep diving. Positive effects in adaptation to hypoxic condition were revealed under argon gas mixture exposure. Under hyperbaric pressure a workload of 100 Wt, the volunteers performed this work 62% higher in 15% argon-oxygen mixture than in 15% nitrox. We conclude that argon could be assumed as a physiologically active gas actively participating in redox-reactions and causing increased resistance of the organisms to hypoxic hypoxia.