Changes in Heart Rate Autonomic Regulation in Girls at The Age of 10–11 with Different Rates of Biological Maturation: A Two-year Study

Abstract

The authors conducted a two-year study of 60 girls aged 10-11. The analysis of the features of heart rhythm autonomic regulation in girls with different biological maturation rates revealed the following. The girls with slower sexual and physical development rates at the age of 10 are marked with higher values of very-low-frequency (VLF) waves, lower values of the high-frequency component of HF than a group of children having the above-average level of physical and sexual development. The groups of 10-year-old girls with different physical and sexual development levels differ in basic anthropometric measurements, body composition parameters, and basal, specific, and norm-based metabolic rates. By the age of 11, girls with the due acquisition of secondary sexual characters demonstrate an increase in sympathetic influence and a decrease in parasympathetic effect on HR’s variability. The obtained data indicate a relative lag in the functional development of the cardiovascular system autonomic regulation in girls with the delayed acquisition of secondary sexual characters at the age of 10 compared to the group of children with the above-average level of physical and sexual development.