Young people who spend more than two hours a day in front of screens have lower cognitive abilities than those whose exposure is more limited, say Canadian researchers from Ottawa and Carleton universities.
Dr. Jeremy Walsh and his colleagues analyzed data from the 10-year Adolescent Brain Cognitive Development observational study that examined the brain development of 4520 9- and 10-year-old Americans in 20 regions of the country.
On average, these children spent 3.6 hours per day in front of a screen (mobile phone, tablet, computer, television), which is well beyond the Canadian 24-hour Movement Guidelines which are:
- less than 2 hours of screen;
- 9 to 11 hours of sleep;
- at least one hour of physical activity per day
Researchers therefore observed children’s cognition in relation to their levels of physical activity, leisure time spent in front of a screen, and sleep time. Cognition was measured by taking into account language skills, episodic memory, executive function, attention, working memory, and processing speed.
Did you know?
American pediatricians recommend not to put a child in front of the television before the age of 18 months.
Children aged 9 and 10 whose lifestyle matched the physical activity, screen time and sleep recommendations of the Canadian 24-Hour Movement Guidelines had superior overall cognition.
We have clearly seen the importance of each hour of a day for the cognitive health of children.
“The greatest benefits for cognition were observed in children who met screen time and sleep recommendations or recommendations for screen time alone,” says the physician.
However, the researchers say that children who met a high number of recommendations had superior overall cognition.
Lifestyles to change
The study found that only half of the children met sleep recommendations, 36% recommended screen time and only 17% recommended physical activity.
Changes in children’s lifestyle toward low levels of physical activity, falling sleep hours, and the omnipresence of screens can pose a threat to cognitive development.
The details of this study are published in The Lancet Child & Adolescent Health .