Tymoshenko K. Features of structural and functional rearrangements of microhemodynamics during adaptation to physical activity

A parallel study of microcirculation (MCC) features in humans and experimental animals and ultrastructure of muscle tissue in response to dosed physical training (DPT) was conducted. It is shown that organisms regardless of the degree of fitness should be distributed by the level of microcirculation index (IM), since the initial level of IM determines the type of response of the MCC to the DPT. At low baseline IM growth of blood supply to muscle tissue is provided by an increase in the number of functioning capillaries (FC) – approximately the same in trained and untrained animals. In the case of high initial IM values, the development of an adaptable reaction to the DPT occurs due to an increase in the blood flow rate in the MCC system. For the first time it was revealed that the initial reaction to the load in the muscle tissue of an untrained organism concerns the opening of reserve capillaries and is not provided by rearrangements in its mitochondrial apparatus. Long-term training contributes to the activation of angiogenesis and morphogenesis of mitochondria (MС). Consequently, the increase in the number of FC (namely – the adaptable of reserve capillaries) is an urgent compensatory reaction at low IM values, and changes in energy metabolism to rapid compensation for unformed adaptation to the DPT. It was also revealed that in untrained and trained animals, DPT causes in the muscle signs of hypertrophy and local edema of subsarcolemal areas of fibers, which is considered to be a sign of violation of intercellular metabolism. Increased pinocytosis and an increase in the number of free ribosomes are recorded, which can be considered as indicators of intensification of metabolic processes in the cell, namely protein synthesis and metabolite transport, which, together with the opening of reserve capillaries, are indicators of the first immediate adaptive response to DPT. Such changes, depending on the fitness of the body, have a different degree of severity and are inherent in both the tissue of the calf muscle and myocardium.