Participants ranged from eight to eleven years old. Illustration: Rame Abdulkader
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U of O study measures impact of physical activity, sleep, screen time in children

According to a new study, out of physical activity, sleep, and screen time, screen time is the greatest factor in cognitive development.

Researchers at the University of Ottawa conducted a year-long analysis of cognitive functioning in over 4,500 children across the U.S in a study titled, the “Adolescent Brain Cognitive Development.”

The results of the study found that screen time, sleep, and physical activity had major impacts, positive or negative, on the cognitive function of children aged eight to eleven.

What we found in that study was that screen time is the main culprit associated with bad cognitive function,” said U of O medicine professor Jean-Philippe Chaput, co-author of the report and research scientist with the Healthy Active Living and Obesity Research Group.

The observations coincide with the Canadian 24-Hour Movement Guidelines, set out in the 2016 ParticipACTION report card on youth activity. The report recommends children aged five to 13 get from nine to 10 hours of sleep, an hour of structured physical activity, and less than two hours of screen time per day.

We wanted to see if the results backed up the Canadian guidelines that look at the whole day in terms of all-day behavioursnot just physical activity,” said Chaput.Before it was just physical activity alone, now they’re all integrated in one set of guidelines.”

Five per cent of the children met all three guidelines and 37 per cent met the screen time guidelines. Participants who followed all three guidelines performed best overall in the study.

The Adolescent Brain Cognitive Development study analyzed children’s use of iPads and cellphones, whereas previous studies relied on data that was limited to older forms of technology, like television and video gaming.

However, there are limitations to the new findings. The study is cross-sectional, which means the results don’t guarantee a cause. And, because the results were gathered by a questionnaire, the results could be misreported.

Associations can be on both sides,” said Chaput. It could be that kids with bad cognitive function are more likely to sit and move less, so we don’t know what is the chicken or the egg.”

The study looked at MRI data, which Chaput and his team are currently analyzing. The upcoming results will ideally lead to more objective findings and measurements.

When it comes to encouraging positive lifestyle habits and behaviours in children, Chaput says role models count. He encourages parents to be active with their children and remember that behaviours affect cognition and academic performance.

“Sometimes we think it’s one thing or two things, but the whole day matters,” said Chaput. “So if we want our kids to have good grades and to succeed in the future we need to think in terms of the whole day, not just in terms of one or two behaviours that will do the trick.”