ADAPTIVE CAPABILITIES OF MIDDLE SCHOOL-AGED GIRLS DEPENDING ON THE RATIO OF ADIPOSE AND MUSCLE TISSUE

Abstract

The aim: This study aimed to determine the dependence of adaptive capacities of middle school-aged girls with excessive body weight and increased volume of adipose tissue on the ratio of adipose and muscle tissue volume. Materials and methods: 52 female subjects aged 10-12 years were examined and divided into 3 groups according to their BMI. Cardiorhythmogram was recorded in all subjects using the “CardioLab” hardware-software complex. The indices of heart rhythm variability (HRV) were determined at rest and after an active orthostatic test based on the recorded cardiothythmogram. Body weight and total fat tissue amount were determined using the Tanita BC-601 device. Results: The analysis of HRV indices revealed features of autonomic rhythm regulation depending on morphological body features of the middle school-aged girls, namely, on the amount of fat and muscle tissue. Obese subjects had higher values of VLF %, LF % and LF/HF indices, which indicate a higher sympathetic influence on cardiovascular system activity and less significant parasympathetic division of the autonomic nervous system (ANS), as well as the PARS index. This trend of HRV indices points to an unsatisfactory level of adaptation, tension of the regulatory systems and the possibility of their failure. In contrast, subjects with normal and excessive body weight had higher values of HF ms2, HF % and TR ms2, and lower values of VLF %, LF/HF and PARS, which points to the dominance of the parasympathetic part of the ANS, lower level of tension in their regulatory systems, a satisfactory level of adaptation, satisfactory functional reserves of the cardiovascular system and high capabilities of the body. Conclusions: Obese girls exhibited disturbances in the ANS functional state towards sympathicotony and increased functional activity of suprasegmental ANS divisions, which can be interpreted as an autonomic dysfunction.