A new study by a researcher at Tel Aviv University has found that when children begin to change their sleep patterns, adolescence may not be far behind.
The findings of the study by Professor Avi Sadeh of the Department of Psychology were reported in a recent issue of the journal Sleep. The study was supported by a grant from the Israel Science Foundation.
Over a two-year period, sleep onset was significantly delayed by an average of 50 minutes in 72 children age 10 and 11 at the start of the study. Sleep time was significantly reduced by an average of 37 minutes. Girls had higher sleep efficiency and reported fewer night awakenings than boys, but for both, initial levels of sleep predicted an increase in pubertal development over time.
The children who participated in the study (94 at the start and 72 by the time the study ended) kept sleep diaries and wore an actigraph on the wrist to measure biological functions. An initial assessment was taken at the beginning of the study, with a second and final assessment taken at one-year intervals.
According to Sadeh, the findings suggest that the neurobehavioral changes associated with puberty may be seen earlier in sleep organization than in bodily changes. However, he adds, “psychosocial issues such as school demands, social activities and technological distractions can also lead to the development of bad sleep habits.”
“It is very important for parents to be aware of the importance of sleep for their developing children and to maintain supervision throughout the adolescent years,” he says. “School health education should also provide children with compelling information on how insufficient sleep compromises their well-being, psychological functioning and school achievements.”
Sadeh also notes that as children become adolescents, they tend to go to bed later and get up later as well. They also sleep less, which is associated with daytime sleepiness, sleep less during the week and more during the weekend to compensate.
Significant differences were seen between sleep on Friday nights and school nights given that Israel has a six-day school week, with Friday the only day not followed by school.
On Fridays, sleep onset was delayed, sleep time extended and sleep quality poorer than on other nights. There was no difference between puberty status or gender, suggesting that the tendency to “catch up” on sleep over the weekend is steady throughout early adolescence.
Sadeh says the findings may have other implications as well. “A deeper understanding of the interrelationships between sleep and pubertal maturation may provide new insights into the emergence of vulnerabilities for behavioral and emotional health problems in early adolescence. This could improve prevention and early intervention efforts.”