Over the last years, sleep habits evolution from childhood into adolescence has been identified as a preferential target for investigators. The present study examines the objective sleep patterns as recorded by Actiwatch in elementary–10.8 years children and junior high school–14.2 years adolescents. During schooldays and weekends elementary school children have constant sleep patterns. Significant differences were found in junior high school adolescents, first in comparison with elementary school subjects and second, between schooldays and weekends. During schooldays, adolescents get insufficient sleep, which they try to recompense during weekends. The majority of sleep parameters showed significant variation in weekends in contrast to schooldays. Present objective data revealed, that major changes in sleep patterns occur in adolescents. Adolescents, parents and health practitioners should realize the effects of chronic sleep insufficiency and develop new strategies in order to promote coherent sleep hygiene