Spectral analysis of heart rate variability in children and young adults during sleep and awake states

Maturation of heart rate variability was studied by comparing the heart rate variation of 26 children and young adults between 5 and 24 years of age when awake and during quiet and active sleep. Spectral analysis was used to determine the intensity of the variation in each of two main frequency bands in which variation occurs: LF 0.03–0.15 Hz and HF, 0.15–0.6 Hz. The results of the study show that many children have reached a mature pattern by 5 years of age.