A new study, published in The Lancet Child & Adolescent Health, examines the relationship between physical activity, screen time, and adolescent mental wellbeing internationally. The researchers found that more screen time and less physical activity were associated with lower life satisfaction and more somatic complaints in adolescents from high-income countries.
The researchers, led by Dr. Asaduzzaman Khan, of the School of Health and Rehabilitation Science at the University of Queensland, write:
“Given that both excessive screen time and insufficient physical activity are prevalent during adolescence and can persist into adulthood, understanding how levels of screen time and physical activity are jointly linked with mental wellbeing is important for reducing their impact on mental health.”
They call for further research and suggest that public health strategies that encourage physical activity and decrease screen time be implemented to promote adolescents’ mental wellbeing.
Since the beginning of the 21st century, declines in the mental well-being of adolescents from high-income countries have been well-documented. Poorer mental wellbeing can lead to developmental issues, difficulty attaining educational goals, and negatively affect overall health.
High levels of screen time have been shown to negatively impact mental wellbeing, including the experience of depressive symptoms, which is concerning considering adolescents typically spend a lot of time on their screens. Alternatively, regularly engaging in physical activity has been shown to positively affect mental well-being and even protect against depression.
While available research on the relationship between physical activity, screen time, and mental wellbeing has indicated that a lot of time on screens and minimal physical activity is detrimental to the psychological health of adolescents, research conducted so far has only focused on single countries or communities as opposed to a larger sample of adolescents.
In the current study, Dr. Khan and colleagues utilized data from the Health Behaviour in School-aged Children (HBSC), which captured the health and wellbeing of 577,475 adolescents from 42 countries across Europe and North America.
Less time on screens and more physical activity were positively associated with adolescents’ mental wellbeing and overall life satisfaction.
The researchers write, “Collectively, our findings provide support for the current recreational screen time recommendation of 2 h or less per day and the physical activity recommendation of 60 min or more per day for health and wellbeing.”
Dr. Khan and colleagues observed that the negative effects of screen time on adolescents seemed to be related to how much time they spent on screens, with girls experiencing lower mental wellbeing past 2 hours of screen time per day and boys past 4 hours per day.
They encourage future research to investigate how certain types of screen time may or may not differently impact adolescents’ mental wellbeing, citing the growing research that demonstrates how passive, sedentary behavior like watching T.V. can increase the risk of depression. In contrast, mentally active sedentary behavior like reading may protect against depression.
The benefits of physical activity, such as better satisfaction with life and decreased psychosomatic concerns, were supported in this study.
Based on their findings, the researchers advocate for a holistic approach to public health initiatives targeted at lifestyle changes, encouraging the promotion of physical activity and reducing screen time to achieve better outcomes.
Further, they found that physical activity was beneficial to the adolescents’ mental wellbeing regardless of how much screen time they had. On the other hand, screen time negatively affected psychosomatic concerns even among adolescents who engaged in regular physical activity.
Moreover, the researchers’ work highlights gender disparities in mental wellbeing, with boys reporting better mental wellbeing than girls. Yet, their research suggests that the effects of screen time and physical activity are likely similar across genders.
Major strengths of this study were its large sample size and its use of innovative techniques to examine the differences in experiences based on gender. However, a limitation of the study is that its design does not allow the researchers to determine causality in the relationships between screen use, physical activity, and mental wellbeing.
Additionally, as the data analyzed was collected between 2006 and 2014, there is a chance that it does not represent the experiences of current adolescents. Therefore, further research is needed to examine how different types of screen use and physical activity affect adolescents’ mental wellbeing.
Overall, this study found important relationships between screen time, physical activity, and wellbeing using a large sample of adolescents across 42 high-income, Western countries. The findings of this study have implications for public health interventions and research.
The authors conclude:
“Specifically, future public health strategies to promote adolescents’ mental wellbeing should target reducing screen time and increasing physical activity simultaneously. Given the importance of health behaviors for population health and wellbeing, future prospective research should investigate the causality of the joint associations of screen time and physical activity and examine interrelationships between screen time types, dose and types of physical activity, and mental wellbeing of adolescents.”
Khan, A., Lee, E. Y., Rosenbaum, S., Khan, S. R., Tremblay, M. S. (2021). Dose-dependent and joint associations between screen time, physical activity, and mental wellbeing in adolescents: an international observational study. The Lancet Child & Adolescent Health, 5, 729-738. https://doi.org/10.1016/ S2352-4642(21)00200-5 (Link)