FEATURES OF HEART RHYTHM VARIABILITY, BODY COMPOSITION AND PARAMETERS OF BIOIMPEDANESOMETRY IN GIRLS DEPENDING ON THE RATES OF BIOLOGICAL MATURATION
The aim is to study the features of heart rate variability, body composition and parameters of bioimpedancemetry in 10 year old girls depending on the rate of biological maturation. Methods: 72 girls were examined using electrocardiography, anthropometry, bio-impedansometry. Results. The average power values of very low-frequency waves (VLF) of the cardiac rhythm are higher in retarded girls (2 128.1 ± 507.29) ms<sup>2</sup> compared to accelerated (1,262.0 ± 179.54) ms<sup>2</sup>. Accelerated girls demonstrated an increase in the power of oscillations of high-frequency component HF (ms<sup>2</sup>) of the cardiac rhythm (2 257,8 ± 475,27), an increase in the percentage of high-frequency waves HF% (42,2 ± 5,33), a decrease in the LF/HF correlation (1,06 ± 0,288) in comparison with retarded ones (HF (ms<sup>2</sup>) - 1 796,0 ± 426,76, HF% - 27,3 ± 4,20, LF/HF - 2,35 ± 0,626). A statistically significant decrease in the normalized basal metabolism was shown: (46.9 ± 0.86) kcal / kg - retarded girls, (37.9 ± 1.45) - accelerated and increase in body fat mass: (15.5 ± 11.52) % - retarded, (25.0 ± 1.655) - accelerated. Conclusions: 1) differences in spectral parameters between groups with different biological ages were revealed in ten-year-old schoolgirls in terms of VLF and HF components, which indicates an increase in the activity of the segmental part of the autonomic nervous system during puberty; 2) the group of girls with a low level of anthropometric indicators and puberty is characterized by higher VLF values, lower HF values compared to the group with a level of physical and sexual development above average; 3) groups of girls with different levels of physical and sexual development differ not only in basic anthropometric indicators, parameters of the component composition of the body, but also in terms of the basic, specific, normalized metabolism; 4) a statistically significant decrease in the rate of normalized basal metabolism was found in the group of accelerated girls, compared to retarded ones.