Limiting Screen Time Actually Boosts Physical Activity, But Only In Kids: Study

Can reducing screen time really help increase physical activity? It's effective in children, but not so much in adults, a new study has found.

Both children and adults nowadays tend to spend a lot of their leisure time using digital screens and this can "affect their health and behavior," noted the authors of the new study, published Monday in JAMA Pediatrics.

People try to break away from this habit by putting limits on screen time. However, there has been debate on whether the use of screen time actually takes away from the time meant for physical activity, or if it's simply replacing some other sedentary activity, according to the University of Southern Denmark (SDU) Faculty of Health Sciences.

The researchers sought to answer this question through a trial that involved 89 families, consisting of a total of 181 children and 184 adults. They were randomly assigned to either the intervention group (45 families) – who had to limit screen time to less than three hours for two weeks, or the control group (44 families) – who could go on with their usual screen time. Their physical activities were assessed using accelerometers attached to the thigh and trunk.

"We found that children in the screen reduction intervention group had an average of 45 min more daily physical activity compared to children in the control group," Jesper Pedersen, of SDU, noted in the news release. "The difference between the groups were largest on weekend days where children in the screen reduction group had an average of 73 min more physical activity compared to children in the control group."

The difference was "statistically significant," the researchers said. The results also suggest that screen time after school or on weekends "displaces" other activities where they can actually move more, said Anders Grøntved, one of the study authors.

This shows how balancing kids' screen time "should be a public health priority" because it can "substantially" increase their physical activity. The benefits of physical activity include fostering healthy growth and development in young people, improving overall well-being and helping to enhance thinking, judgment and learning skills, according to the World Health Organization (WHO).

However, the researchers didn't find the same results among the parents, who were also a part of the study. Specifically, they didn't find a "significant difference" in their daily movements during leisure time, whether they were in the intervention or the control group. It's possible that this could be because adults tend to be "less spontaneous" in their physical activities compared to children.

"Although the results suggest that reducing screen media use is an ineffective way of increasing adults' daily movement, it may still be a good idea for adults to balance their screen use in the home because we know from previous research that parental screen use in the home is strongly associated with children's use of screen media," Grøntved said. "A reduction of recreational screen use among parents could be a key to balancing children's own use."