Most parents know the drill. Bedtime slips later, mornings get harder, and the next day the whole family pays for it. For some kids, that pattern plays out night after night.
A study of more than 8,300 American children has linked short nighttime sleep to measurable differences in brain structure.
Kids sleeping fewer than 9 hours a night had less grey matter in brain regions tied to attention, memory and self-control.
The work, published in The Lancet Child & Adolescent Health in July 2022, drew on the Adolescent Brain Cognitive Development project. Two years later, the brain differences were still there.
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The children were 9 to 10 years old when they joined. Researchers compared the kids with insufficient sleep against closely matched peers who slept more, then followed up at ages 11 to 12.
What the brain scans showed
The children sleeping less than 9 hours had smaller grey matter volume in brain areas tied to decision making, impulse control and memory.
Grey matter is the tissue packed with nerve cell bodies, and in school-age children it is still being shaped by sleep and daily experience.
The sleep-short group also had higher rates of depression, anxiety and impulsive behavior. They had more trouble with memory, problem solving and everyday decision making too.
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Lead author Ze Wang, a professor of diagnostic radiology and nuclear medicine at the University of Maryland School of Medicine, spoke to that persistence.
"These differences persisted after two years, a concerning finding that suggests long-term harm for those who do not get enough sleep," Wang said in the university's announcement.
The study is observational, so it cannot prove that short sleep caused the brain differences.
But the matching method compared children who looked alike on dozens of other factors, which strengthens the link.
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How many hours school-age kids actually need
The American Academy of Sleep Medicine recommends that children 6 to 12 years old sleep 9 to 12 hours per 24 hours on a regular basis. Teenagers 13 to 18 should get 8 to 10 hours.
The academy says children who regularly hit those targets do better on attention, learning, memory and emotional balance.
Those who fall short face higher risks of attention and behavior problems, injury, obesity and depression.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.