Changes in Sleep Patterns Predict Puberty

(December 24, 2009) - Are your 11- and 12-year-olds staying up later, then dozing off at school the next day? Parents and educators who notice poor sleeping patterns (Read about "Sleep") in their children should take note of new research and prepare themselves for bigger changes to come.

The study suggests that changes in children's sleep patterns are evident just before the onset of physical changes associated with puberty.

"It is very important for parents to be aware of the importance of sleep for their developing children and to maintain their supervision throughout the adolescent years," says Avi Sadeh, who reported his research findings in a recent issue of the journal Sleep. "School health education should also provide children with compelling information on how insufficient sleep compromises their well-being, psychological functioning and school achievements."

Sleep-wake patterns were observed subjectively through the use of sleep diaries and objectively through the use of an actigraph, which the 94 children involved in the study (10 and 11 years old at its start) wore on their wrists. The assessment was repeated annually for two successive years. Eighty-two children completed the second assessment, and 72 completed the third assessment.

According to Sadeh, sleep-wake organization undergoes significant changes during the transition to adolescence. These changes include a delayed sleep phase, which involves a tendency towards later bedtimes and risetimes; shorter sleep, which is associated with increased levels of daytime sleepiness; and irregular sleep patterns, which involve sleeping very little on weekdays and sleeping longer during weekends to compensate. During maturation, adolescents also develop a greater tolerance for sleep deprivation or extended wakefulness.

Results of the study show that over a two-year period, sleep onset was significantly delayed by an average of 50 minutes in the study subjects, and sleep time was significantly reduced by an average of 37 minutes. Girls also had higher sleep efficiency and reported fewer night wakings than boys. For both, initial levels of sleep predicted an increase in pubertal development over time. This suggests that the neurobehavioral changes associated with puberty may be seen earlier in sleep organization than in bodily changes.