THE VALUE OF BLOOD OXYGEN CAPACITY FOR THE DEVELOPMENT OF EXERCISE HYPOXIA

The article discusses the factors that can limit oxygen consumption and performance during moderate power work. This study aimed to identify how changes in the oxygen-binding properties of blood affect its oxygen transport function and modes of oxygen mass transfer during exercise hypoxia. We examined 12 adolescent girls aged 14-16 who suffered secondary anaemia due to juvenile bleeding (Hb concentration - 10.9±0.76 g%). For control, 14 healthy girls of the same age were examined (Hb - 12.2±0.14 g%). The girls performed stair climbing for 5 minutes (power of such work ≈ 50 W, intensity ≈ 35-45% of maximum oxygen consumption). As a result of the present study, we analysed various variants of changes in certain indicators of oxygen mass transfer modes. We were able to investigate the role of one of the regulators of the oxygen transport function of the blood, which significantly affects the supply of oxygen to working tissues. It was the oxygen-carrying capacity of the blood, which is determined by the haemoglobin content in the blood. It was found that a decrease in the oxygen capacity of the blood contributes to an increase in the oxygen cost of work and oxygen debt. At the same time, the functions of external respiration and haemodynamics are intensified to a greater extent than in healthy individuals, but their efficiency in supplying tissues and organs with oxygen is sharply reduced, and the degree of exercise hypoxia increases, which is confirmed by the development of venous hypoxaemia.