Depression is not an uncommon mental health condition in children and teens, though too few receive the recommended therapies. Physical activity has been seen as a possible alternative or complementary treatment in younger people since it has been shown to reduce depressive symptoms in adults.

One stumbling block has been that previous studies looking at the relationship between physical activity and depressive symptoms in younger populations either excluded those who also had physical or psychiatric problems, known as co-morbidities, or had very small study populations. A recent study overcomes those issues.

Unsupervised physical activity three times a week was more effective for reducing depressive symptoms than supervised activity.

The meta-analysis included studies involving participants who had had psychiatric or physical co-morbidities and found that physical activity was a big help when it came to easing depressive symptoms in children and teens.

The large quantity of data from meta-analyses such as this one give researchers a way to make a more precise estimate of how various levels of physical activity affect mental health outcomes, Eduardo Bustamante, co-author of a related editorial, told TheDoctor.

The analysis included data from 21 studies and 2,441 participants with an average age of 14 years. Such large datasets also allow researchers to ask questions about how the type of physical activity and characteristics of children affect mental health outcomes, said Bustamante.

Those 13 years old or older who had a diagnosis of mental illness and/or depression benefitted more from physical activity than younger participants with no mental health diagnosis or physical illness.

“This is a very timely study because we have kids spending so much time on screens, which we know is related to depression,” he said. Parents and teachers need to find ways to get kids off screens, and moving around. They need to make the mental health benefits of physical activity one of the intended goals in encouraging kids to be active, Bustamante added.

Unsupervised physical activity lasting less than 12 weeks and occurring three times per week was more effective for reducing depressive symptoms than supervised activity lasting longer than 12 weeks and occurring more often. Participants who were 13 years old or older who had a diagnosis of mental illness and/or depression benefitted more from physical activity than younger participants with no mental health diagnosis or physical illness.

Solitary activities, such as hiking or walking, and team sports can help young people meet the physical activity guidelines recommended by the World Health Organization, the corresponding author of the study, Parco Siu, told TheDoctor. But team sports would have the added advantage of offering them more opportunities for peer interaction.

“We are ready to take that next step and through physical activity work on relationships, self-confidence, and body image,” said Bustamante, an assistant professor of kinesiology and nutrition at the University of Illinois in Chicago.

Going forward, Siu, an associate professor and head of the kinesiology division at the University of Hong Kong, and his colleagues, want to determine effective ways to implement physical activity interventions for children in real-life situations. For example, physical activity could become a larger part of the school curriculum.

The study and related editorial are published in JAMA Pediatrics.