Over 3 hours of sedentary behaviour may up mental health risks in teenagers: Study

Teenagers and adolescents who spend more than three hours a day engaged in sedentary behaviours—which includes playing video games or increased screen exposure—have a higher risk of facing mental health issues such as anxiety and depression, according to a study.

The study, published in the Journal of Adolescent Health, showed that adolescents who spent more than 180 minutes a day on screens for leisure were associated with greater psychological distress at age 17.

Video games were particularly influential, with each additional hour associated with a 3 per cent increase in psychological distress. Those who spent more than three hours a day reading for leisure (especially boys) also reported more psychological distress.

At the same time, moderate screen exposure (between 60 and 119 minutes per day) invested in educational activities, such as doing homework or attending classes, was considered a “protective” factor associated with less psychological distress.

“Sedentary behaviour includes a variety of activities, such as using a computer, watching television, reading, listening to music, or attending class. Most research focuses on analysing total sitting time, but we can have positive sedentary activities, such as attending class and doing homework, for example. And there are activities that are not beneficial, such as spending too much time on the Internet or playing video games,” explained Andre de Oliveira Werneck, doctoral student, at the School of Public Health of the University of Sao Paulo (FSP-USP) in Brazil.

Sedentary behaviour among adolescents has become a growing problem worldwide. Besides increasing physical health risks such as obesity and cardiovascular disease, it can also affect mental health, increasing feelings of anxiety and depression.

To understand, the team from King’s College London in the UK, collected information from 3,675 adolescents—when they were 14 years old and then at the age of 17. At 14, the participants were asked to complete a diary in which they recorded their general physical activity, time spent sleeping, recreational screen time, non-screen recreational time, and educational sedentary behaviour.

At age 17, the same participants reported their psychological distress.

While previous research has shown that reading is associated with better mental health outcomes and other healthy behaviours, the new research suggests that excessive reading may be harmful in some cases.

Adolescents who spend many hours reading are “displacing” time that could be spent on activities with face-to-face or outdoor social interactions, which are protective, leading to greater isolation, the researchers said. In addition, it is possible that some of the reading is done on screen devices (cell phones, computers, or tablets), which is also harmful.

Based on the findings, the researchers suggested interventions such as setting clear limits on screen time; and encouraging more educational and structured screen activities rather than passive recreational screen time.