Metabolic responses of the body to breathing with hypoxic argon–oxygen and nitrogen–oxygen mixtures

Abstract

We have studied metabolic responses of six male volunteers who were exposed to hypoxic nitrogen–oxygen and argon–oxygen respiratory mixtures under hermetic chamber conditions for a long time. We measured the values of 44 biochemical parameters of venous blood, which reflected the state of different parts of metabolism, as well as the state of organs and tissues. Under the conditions of argon–oxygen respiratory mixture with the level of oxygen of 12.8% within the first five days and 12.0% from six to ten days of the experiment, the activation of processes of anaerobic glycolysis and lipolysis with the development of metabolic acidosis was observed. Against this background, biochemical signs of unfavorable changes in the myocardium were recorded. When we used the nitrogen–oxygen respiratory mixture with the level of oxygen of 13.0% during the first five days of the experiment and 12.1% from the sixth to the tenth day, these changes were expressed much more significantly: the activation of lipolysis and a decrease in the level of serum iron were observed and the signs of damage of mitochondria, depression of the kidney function, and development of hypodynamia were recorded. Complete stabilization of metabolic processes was reached only after seven to eight days of the recovery period for both mixtures. These findings lead to the conclusion that it is physiologically more preferable to use oxygen–argon respiratory mixtures at small immersion depths.