Pathophysiological markers of reduced resistance of healthy people to moderate hypoxic hypoxia

BACKGROUND: Despite the abundance of research in the field of high-altitude physiology and medicine, the problem of resistance to moderate hypoxia has not been practically studied. This is partly due to methodological difficulties: the studies were conducted on healthy people and climbers who tolerated the effects of moderate hypoxia well. Such studies have become necessary in connection with the development of hypoxic therapy.

AIM: To search for indicators of the functional state of a person that are highly sensitive to the effects of moderate hypobaric hypoxia.

MATERIAL AND METHODS: The examined group consisted of 65 practically healthy men aged 19–25 years who were selected for work in high mountains. The main indicators characterizing the state of the central nervous system, cardiovascular and respiratory systems were studied in a state of relative rest and when performing a dosed two-stage bicycle ergometric test, in normoxia conditions (altitude 0) and during a pressure chamber rise in the TABAY climate complex (Japan) to altitudes of 3500 and 4500 m Statistically analyzed were the characteristics of the dynamics of indicators during the transition from normoxia to states of moderate hypoxia, correlations between indicators, their sensitivity to hypoxic effects, the significance of reactivity to hypoxic effects and mobilization of the body’s functional reserves in resistance to hypoxia.

RESULTS: It has been shown that the key pathophysiological markers of reduced body resistance to moderate hypoxic exposure are a rapid decrease in the level of peripheral blood saturation, high reactivity of the cardiovascular and respiratory systems to hypoxic exposure, as well as excessive mobilization of the body’s functional reserves in response to additional physical activity.

CONCLUSION: The presented materials confirm that the functional state of a healthy person under conditions of moderate hypoxia at rest is determined by the level of saturation of his peripheral blood. Maintaining saturation at a higher level ensures the maintenance of an optimal level of functional state, physical and operator performance, a lower degree of stress on the respiratory and cardiovascular systems.