The average American child spends 3.6 hours staring at a computer, television, tablet, or smartphone daily -- an amount of screen time associated with inferior cognitive development and academic performance, according to a new study of over 4,500 children between the ages of eight and 11 published in The Lancet Child & Adolescent Health.
Dr. Nicky Mehtani with the ABC News Medical Unit, reports that the study, conducted by Canadian researchers, analyzed American kids using the Canadian 24-Hour Movement Guidelines for Children and Youth. Those guidelines recommend that children get nine to 11 hours of uninterrupted sleep, less than two hours of screen time and at least one hour of physical activity every day.
The children who scored best on tests for assessing language abilities, memory, executive function, attention, and processing speed met those sleep, screen time and activity benchmarks.
Nineteen out of 20 children in the U.S. failed to meet the lifestyle benchmarks. While about half met the sleep recommendation, only 37 percent met the guideline for limited screen time and 18 percent met that for physical activity.
“Evidence suggests that good sleep and physical activity are associated with improved academic performance, while physical activity is also linked to better reaction time, attention, memory, and inhibition,” Dr. Jeremy Walsh, the study’s lead author and a postdoctoral fellow at the University of British Columbia, said in the study’s press release.
Dr. Eduardo Esteban Bustamante with the University of Illinois at Chicago, suggested that the study’s findings about screen time may reflect interruption of important childhood growth cycles.
“Each minute spent on screens necessarily displaces a minute from sleep or cognitively challenging activities,” Dr. Bustamante wrote in a commentary that accompanied the study. “In the case of evening screen use, this displacement may also be compounded by impairment of sleep quality.”