Peculiarities of parametric descriptions of human reaction in response to stable hypoxic stimulus

Objective. The purpose of the paper is to examine individual sensibility and resistance to stable hypoxic stimulus in healthy males. Materials and Methods. A total of 159 apparently healthy adult males aged from 18 to 60 were examined. Hypoxia was formed on the basis of rebreathing method. The rate of hypoxic stimulus growth was 1.7 % per minute. The content of carbon dioxide in the respiratory gas mixture did not exceed 0.68 %. Each hypoxic test lasted for 14 minutes. Starting from the fifth minute of exposure the oxygen content in the inhaled air was within 12±1 %. The authors suggest an algorithm for registering the moment when the degree of saturation of blood oxyhemoglobin in a trial subject with oxygen began to decrease in relation to the initial value under the influence of the gradual reduction of this very gas in the inhaled air. Resistance to hypoxia was determined by the reduction value of oxyhemoglobin saturation degree with oxygen at the 10-14th minute of exposure under oxygen deficiency. Results. It was found out that in a sample of 97 trial subjects there were all possible combinations of individual sensibility and resistance levels to hypoxia. At the same time in a group of 62 professional athletes a combination of low sensitivity with high resistance to oxygen deficiency prevailed. This allowed us to consider the reduction value of oxyhemoglobin saturation degree with oxygen at the 10-14th minute of exposure under oxygen deficiency to be a form of sensitivity to hypoxia and to justify resistance to oxygen deficiency as an ability to save normoxic limits of oxygen supply to its final delivery points in the mitochondria.