A Longitudinal Study of the Sleep-Wake Cycle in Children Living on the Same School Schedules

The aim of this work is to study the human' SWC development in the first six years of life, in a longitudinal approach. Six boys, attending the same kindergarten at University of Sao Paulo, participated in the study. Data were collected on five different occasions, from the second to the sixth year of life. On each occasion, the sleep/wake behavior was followed for seven consecutive days (Sunday to Saturday) by an observer at the kindergarten and at home by the parents. Mean total sleep duration as well mean diurnal sleep duration (episodes from 7 AM to 7 PM) and night sleep duration (7 PM to 7 AM) were obtained for all subjects. Data were compared by ANOVA for repeated measures and processed using the Fast Fourier Transform to obtain the power spectrum of the sleep/wake oscillations. Results were submitted to a test of compound periodicities, to detect the significant components of the spectrum. This test generates, for each frequency, a value (Y), which represents the contribution of this frequency to o...