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Back to SearchA study published today in The Lancet Child and Adolescent Health, involving data for more than 577,000 adolescents (ages 13 to 15) from 42 North American and European countries, finds that increased physical activity is clearly associated with better mental wellbeing and increased recreational screen time, beyond 2 hours per day, is detrimentally related to mental wellbeing. It is the first study to show such clear relationships in a large multi-country sample.
The paper is an international collaboration between Canadian and Australian researchers, led by Dr. Asad Khan of the University of Queensland with Dr. Mark Tremblay, a senior scientist at the CHEO Research Institute and professor of Medicine at uOttawa, its senior author.
“We provide compelling evidence that after about 2 hours of daily recreational screen time, adolescent mental wellbeing declines in a dose-dependent fashion – the greater the screen time, the greater the symptoms,” says Dr. Tremblay, who is also President of the Active Healthy Kids Global Alliance. “Being physically active for 60 minutes or more per day was progressively beneficial for mental wellbeing beginning at one day per week – more is better.”
Only 19% reported they were physically active every day and the average recreational screen time approached 6 hours per day. Data were collected long before the COVID-19 pandemic, where dramatic reductions in physical activity and increases in screen time have been observed globally, sounding alarm bells about the mental and physical wellbeing of our youth.
The researchers found that mental wellbeing can be promoted, even in the presence of high recreational screen time (e.g., greater than 8 hours per day), by increasing physical activity levels. For example, among adolescents reporting more than 8 hours of screen time per day, dramatic increases in life satisfaction and dramatic reductions in psychosomatic complaints are seen in those who are physically active each additional day per week.
These findings are particularly relevant in the presence of the pandemic, which has resulted in increased isolation and extended time indoors, provoking increased screen time and decreased physical activity. Public health strategies to promote adolescents’ mental wellbeing should aim to decrease screen time and increase physical activity simultaneously, suggests Tremblay.
“Adolescents’ movement behaviours are suboptimal at the best of times, and consistent with premature mental and physical health conditions. The COVID-19 pandemic has exacerbated this worrisome trend. We must support, encourage and facilitate a recalibration of behaviours towards healthier lifestyles of our youth as a matter of priority,” Tremblay implores.
The study, “Dose-dependent and joint associations between screen time, physical activity, and mental wellbeing in adolescents: an international observational study,” is published in The Lancet Child and Adolescent Health (DOI: https://doi.org/10.1016/S2352-4642(21)00200-5).
The authors have no declared conflicts of interest and this research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
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Professor Mark Tremblay, mtremblay@cheo.on.ca, 613-254-8482
Associate Professor Asad Khan, a.khan2@uq.edu.au, +61 434 532 151, @Asad_K88
About the CHEO Research Institute
The CHEO Research Institute coordinates the research activities of CHEO and is affiliated with the University of Ottawa. The seven programs of research at CHEO RI focus on a full spectrum of pediatric topics. CHEO Researchers are known internationally for their research in the areas of brain injury, genetics/rare disease, cancer, and healthy active living to name a few. At the CHEO Research Institute, discoveries inspire the best life for every child and youth. For more information, visit www.cheori.org.