THE PROBLEM OF AGE PHYSIOLOGICAL NORM WHILE ASSESSING INDEXES OF HRV IN INFANTS
The urgency of heart rate variability study in infants is shown to assess the adaptive capacities of the child's body. The age features of autonomic regulation of heart rate are presented. Increased activity of humoral channel regulation of heart rate occurs in 3–4 months of infant's life, and increased tone of parasympathetic division of autonomic nervous system has been detected in 5–6 months. There is identified gender-specific maturation of regulatory systems during the second half of infants' life. Boys of 7–12 months have shown a higher level of compensatory-adaptive capabilities resulting in higher activity of humoral regulation of cardiac rhythm channel while reducing the influence of the central if compared with girls. Based on the analysis of motion activity and heart rate variability indexes one can ground three types of autonomic regulation of heart rate variability in infants: sympathetic, hypersympathetic and relatively vagotonic. The main indexes reflecting the state of regulatory systems are indexes of the total power spectrum (ТР) and the stress index (SI).