Regular physical activity improves physical and mental health. Conversely, is screen time unfavorable to cognition? Studies are mixed on the subject, but all agree on the importance of limits in children. "Limiting children's screen time is linked to better cognition", reaffirms this very large Canadian study presented in the Lancet Child and Adolescent Health.
Researchers from the Children's Hospital of Eastern Ontario Research Institute, the University of Ottawa, Carleton University (Canada) followed 4,524 children from the United States, selected from 21 different sites. Their analysis concludes that less than 2 hours of screen time per day is associated with better cognitive test scores.
Less than 2 hours of screen per day? In fact, it was a good idea for this team to assess whether the Canadian recommendations on screen time, sleep and physical activity in children aged 8 to 11 are indeed favorable to mental function, as assessed by a series of tests. These recommendations limit all-screen time to less than 2 hours per day, recommend getting 9 to 11 hours of sleep per night and practicing at least 1 hour of moderate to vigorous physical activity per day. The analysis shows that:
- the children who have the best test results are also those who observe the 3 recommendations;
- however…only 5% of children follow these 3 recommendations; the association identified is therefore not statistically significant or borderline;
- children engage in approximately one hour of physical activity on average 3.7 days per week, use screens on average 3.6 hours per day and sleep on average 9.1 hours per night;
- just over half of the children met the sleep recommendations, while 37% met the time recommendation and only 18% met the physical activity recommendations.
- screen time and sleep accounted for about 22% of the variation between test scores, while physical activity alone did not appear to be related to mental functioning. This suggests that physical exercise would not be an independently favorable factor for cognition (?).
- finally, logically, other confounding factors such as the school level of the children and the socio-professional level of the household also turn out to be linked to the results of the tests.
The researchers point out, despite the statistical limit of the results, that parents should consider limiting the time spent by children in front of the screen and monitor their children's sleep and physical activity times. For better cognitive performance.
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