Sleeping less than nine hours affects children’s brain and behavior

Children aged 9 and 10 who sleep less than nine hours a day have impaired brain development and are more likely to have behavioral problems in the future, according to research published this Friday in the scientific journal The Lancet Child & Adolescent Health. .

The American Academy of Sleep Medicine recommends that children and adolescents between the ages of 6 and 12 get at least nine hours of sleep a day, but many do not follow the recommendation and the researchers wanted to better understand the impact of fewer hours of rest on these young people’s development.

Scientists analyzed data from 8,323 children aged 9 and 10 years. They divided this set into two groups — children who slept less than nine hours (4,181 participants) and those who slept at least nine hours (4,142 participants) — and assessed their neural and behavioral data at baseline and after two years.

Fan Nils Yang, Weizhen Xie and Ze Wang of the University of Maryland School of Medicine and the National Institute of Neurological Disorders and Stroke in the United States considered parameters of mental health, cognition, brain function and structure. For this, they used tests, questionnaires and magnetic resonance images.

First, they looked at sleep patterns over a two-year period and found that as they got older, those who got enough sleep tended to reduce their hours of rest.

Next, the scientists focused attention on behavioral measures. Here, they noticed significant differences for depression, problems with thinking, vocabulary and crystallized intelligence – referring to knowledge derived from past learning and experiences – between those who slept more and those who slept less.

The next step was to assess how sleep duration affected brain networks both at baseline and after two years. They found that there were differences between groups in about 30% of the connections, mainly those in regions of the basal ganglia, which play an important role in regulating the sleep-wake cycle.

The scientists also noticed a significant difference in gray matter volume in 12 of the 184 regions evaluated, a pattern that repeated after two years, suggesting that some structural measures are susceptible to insufficient sleep.

“Our findings suggest that corticobasal ganglia connections play an important role in mediating the effect of insufficient sleep on cognitive and affective functions, and that structural properties of the anterior temporal lobe may contribute to the effect of insufficient sleep on crystallized intelligence. These effects can last for at least two years, highlighting the importance of early sleep intervention in young people to improve long-term neurocognitive development outcomes.”

According to the researchers, more studies are still needed on the lasting consequences of lack of sleep on development. “If confirmed, our findings could provide empirical and theoretical foundations for early intervention programs to improve adolescent developmental outcomes,” they add.

They also emphasize that while the findings show the importance of nine hours of sleep, there is no evidence that overdoing the rest period is positive. “It has not yet been tested how prolonged sleep duration, for example longer than 12 hours, would affect neurocognitive development in adolescents.”