[Composition of exhaled air, gas and energy metabolism and bio- chemical indicators of the blood and urine in humans after long- term exposure to hypercapnia and hypoxia].

Four volunteers were enclosed for 40 days in a hypercapnic environment. Their average age was 41-59 years, body weight, 66-90 kg, and height 173-182 cm. During the study the ambient temperature was 19-23 degrees C, relative humidity, 50 +/- 20%; pO2, 19-19.5%; and pCO2, 1.3%. On test days 21-22 and 38-39 pCO2 was increased to 4% and pO2 was decreased to 17%. The time, within which pCO2 was increased to 4% on test days 38-39 when compared to test days 21-22, grew 1.5-fold and amounted to 40 hours. The subjects had three meals a day, consuming canned foodstuffs, the caloric value of which was 2982 kcal/day. In the study the following parameters were measured: malonic dialdehyde in venous blood; catalase, lactate, pyruvate, urea, acid-base content, gases in capillary blood; total nitrogen, ammonia, urea, creatinine and uric acid in 24-hour urine samples. Nitrogen balance and protein nutrition index were calculated. Results were processed using Student's t-test. During exposure lipid peroxidation increased and catalase decreased; malonic dialdehyde in blood increased, being correlated with lower hydrocarbons in exhaled air; gas and energy turnover during hypercapnic intervals enhanced. The above changes in the exhaled air composition, gas and energy turnover, biochemical blood and urine parameters remained within adaptation norm. By the second week of the recovery period the above parameters, except for nitrogen metabolism which remained slightly inhibited, returned to the normal.