Polygraphic records of EEG, ocular movements, respiration, and heart rate were made
continuously in 10 full term babies between 2 and 7 days old. Power spectral analysis
was then computed for heart and respiratory rate. The period durations obtained by
this method ranged from 20 to 70 minutes. Most of the power spectra showed two maxima.
In many cases cycles of respiration and heart rate were not identical. The experiments
show that newborns have two separate cycles with different period durations. Most
probably the shorter cycle originates from the fetal life, the longer one represents
the development of the periodicity of the adult.
Sleep - development of periodicity - newborn infants - heart rate - respiratory rate