Less screen time improves Children’s brain power.

Children’s brain power is improved if they spend less than two hours a day looking at screens, according to a study.

Researchers said that parents should try to limit their offspring’s recreational screen time, including periods playing video games, using social media and watching television.

The study followed more than 4,500 US children aged between eight and 11, noting how much of their day involved recreational screen time, physical activity and sleep.

They compared them with Canadian guidelines that recommend sleeping between nine and 11 hours, being physically active for an hour, and limiting recreational screen time to less than two hours a day.

The more individual recommendations that the child met, the better their scores on cognition tests. The strongest link was between meeting the screen time guideline and better cognition. Complying with the screen time and sleep recommendations also appeared to improve cognitive development.

Jeremy Walsh of the Cheo Research Institute in Ottawa, said: “More than two hours of recreational screen time in children was associated with poorer cognitive development.

“More research into the links between screen time and cognition is needed, including studying the effect of different types of screen time, whether content is educational or entertainment, and whether it requires focus or involves multitasking.

“Paediatricians, parents, educators and policymakers should promote limiting recreational screen time and prioritising healthy sleep routines.”

Just over half of the children met the sleep recommendation, 37 per cent the screen guideline and 18 per cent the physical activity preference. Only one child in 20 in the study met all three guidelines, with the average child spending 3.6 hours a day on recreational screen time.

Meeting the physical activity recommendation alone showed no link to performance. The authors said that this was “surprising” because it ran counter to previous research and the measure used might not have been specific enough.

Data on how the children spent their time was compiled using questionnaires and the children had cognition tests on episodic memory, executive function, attention, working memory and processing speed.

The scientists took into account household income, parental and child education, ethnicity, pubertal development, body mass index and whether the child had had a traumatic brain injury.

The study, published in The Lancet Child & Adolescent Health journal, is observational, so cannot establish cause and effect. However, Dr Walsh said: “Behaviours and day-to-day activities contribute to brain and cognitive development in children, and physical activity, sedentary behaviour and sleep might independently and collectively affect cognition.”

Max Davie, officer for health promotion at the Royal College of Paediatrics and Child Health, said: “Too much screen time may be associated with a range of issues, however, there seems little evidence that this is causal, or that removing screen time without replacing it with cognitively enhancing activities is an effective intervention. Parents need more support to have conversations with their children about screen time and its impacts. That’s why [we] will be producing guidance on this issue for professionals, parents and young people in early 2019.”