How a lack of sleep damages a child’s brain A lack of sleep leads to ongoing losses in brain capacity and cognitive performance

Lasting Consequences: A study showed that when elementary school children consistently lack sleep, it has a lasting effect on their brains and mental development. According to the study, children who sleep less than nine hours a night have less gray matter in areas of the brain associated with attention, impulse control and memory. In addition, they were more likely to have behavioral problems and cognitive deficits. These differences were still detectable two years later.

Sleep is vital to our brain. During this rest period, waste is eliminated, memory is sorted out and synapses are recalibrated. If we don’t sleep, we become more irritable, more sensitive to pain, have difficulty concentrating and tend to distort memories. Studies also show that prolonged sleep deprivation also increases the risk of cardiovascular disease and can damage brain cells.

Lack of sleep is particularly harmful to children. Because their developing brain needs a night’s rest more urgently than adults. That’s why sleep physicians recommend that elementary school-aged children get at least nine hours of sleep.

Primary school children in a comparative test

But what happens when kids consistently get too little sleep? Now Van Nils Yang at the University of Maryland in Baltimore and colleagues examined this in more detail. To do this, they evaluated data on 8,323 girls and boys between the ages of 9 and 10 when the study began. By surveying parents, the researchers determined the average amount of time the children slept each night.

All children were psychologically and medically examined at baseline and again two years later, and their cognitive functioning was tested. The team also examined the children’s brain anatomy and function using functional MRI at baseline and two years later. For evaluation, children who slept or did not sleep enough were compared in pairs so that their background and living conditions were as similar as possible.

“We tried to reconcile the two groups as best we could so that we could better understand how sleep deprivation affects the pre-adolescent brain in the long term,” says colleague Yang Zi Wan,

Less gray matter and cognitive deficits

The result: “We found that children who slept less than nine hours a night had less gray matter and smaller volume in certain brain regions than children who got enough sleep,” Wang reports. “The affected areas of the brain are responsible for attention, memory, and impulse control.” These include parts of the cerebral cortex in the temporal lobe, among others. At the same time, there were also differences in the functional connections between different brain regions.

However, the consequences of poor sleep were also reflected in children’s behavior and cognitive abilities: on tests of memory, problem-solving skills and decision-making skills, children who slept less than nine hours performed worse than their best-of-peer rest. Also, impulsive, depressed or anxious behavior was more common in these children than in those who regularly slept more than nine hours.

“These differences also remained detectable after two years – a worrying finding because it indicates long-term harm to children who don’t get enough sleep,” says Wang.

It must be at least nine hours

Sleep physicians recommend a night’s sleep of at least nine hours for children between the ages of nine and twelve. “But in the hectic daily life between schoolwork and extracurricular activities, this can quickly get lost,” says co-author Albert Reis of the University of Maryland. The use of computers, tablets, and mobile phones in the evening also contributes to shortening children’s sleep times.

“But now we’re seeing how much damage that can do to a child’s development,” Reese said. According to the scientists, their findings confirm that adequate sleep is important for children’s brain development – and how harmful a constant lack of sleep can be. (The Lancet Child & Adolescent Health, 2022; doi: 10.1016/S2352-4642 (22) 00188-2)

Source: University of Maryland College of Medicine

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