Staying active as a teenager protects against depression, study finds

Staying active as a teenager does more than strengthen your body. It also protects your mental health. A new long-term study has revealed that when adolescents boost their physical activity, they are far less likely to develop symptoms of depression. The findings provide fresh insight into how movement shapes the mind during key years of development.

Researchers from the Norwegian University of Science and Technology followed children from early childhood until adulthood to uncover how physical activity and mental health are linked. The work drew from the Trondheim Early Secure Study, one of the most detailed investigations of child development ever conducted in Europe.

The study relied on a group of 873 participants, tracked from age six until age eighteen. Data were collected every two years. Instead of relying on self-reports, the team used accelerometers, devices that provide objective and reliable measurements of daily activity. These instruments were worn for seven days during each data collection period. At the same time, clinical interviews assessed mental health, producing a rich picture of changes across twelve years.

"Young people who are less physically active over time have an increased risk of developing symptoms of depression," explained Professor Silje Steinsbekk of the Norwegian University of Science and Technology. The work was recently published in the Journal of the American Academy of Child & Adolescent Psychiatry.

Activity was not simply measured by duration. The researchers paid close attention to the proportion of time participants spent in more vigorous forms of exercise. These bursts of effort, such as running or team sports, appeared especially important for mental health benefits.

"This finding was true for teens who were 14 to 16 years old and 16 to 18 years old," Steinsbekk noted. "Both the sum of daily physical activity, and the proportion of activity that is more intense and particularly important for our health, turned out to protect against symptoms of depression." The data pointed to a clear protective effect during mid-to-late adolescence. Teens who moved more during those years were more resilient against depression symptoms than those who stayed inactive.

Interestingly, the effect did not hold steady across all ages. The researchers found no clear link between movement and depression in children between ages 10 and 14. For some, the relationship even appeared reversed. "From 10-12 and 14-16 years, those who had more symptoms of depression were more likely to become less physically active," Steinsbekk said.

That finding suggests that in early adolescence, mental health difficulties may reduce motivation or energy for activity. By contrast, once teens reach their mid-teens, building up more physical activity appears to actively protect against future depressive symptoms.

To test whether other factors shaped the results, the team examined self-perceptions, body image, and involvement in organized sports. These influences might be expected to play a role in how activity affects mood, but they did not change the central connection. Physical activity itself seemed to matter most.

The researchers also studied whether long hours of sedentary time, such as sitting in front of screens, might play a role. They found no link between time spent sitting and depressive symptoms. Likewise, no difference appeared between boys and girls.

The conclusion was clear: for teenagers between 14 and 18, being active matters for mental health. Movement during those years does more than maintain physical fitness. It serves as a safeguard against developing symptoms of depression.

"Young people who increase their physical activity level from the age of 14 and a few years later have a lower risk of developing symptoms of depression than they would otherwise have. For this age group, it may appear that physical activity protects against symptoms of depression," said Steinsbekk. The research offers an important reminder for families, educators, and health professionals. Supporting teens in finding enjoyable ways to stay active may help them build resilience during one of life’s most challenging stages.

The Trondheim study highlights how carefully designed long-term research can reveal insights that shorter projects miss. By following the same children across twelve years, scientists were able to track the changing role of activity at each age.

The results align with a growing body of evidence showing that the benefits of movement extend beyond muscles and bones. Exercise influences brain chemistry, reduces stress hormones, and strengthens emotional regulation. These effects become particularly important during adolescence, a time when mental health challenges often emerge.

The study also points toward the value of interventions that encourage teens to increase activity during the high school years. Organized sports, community programs, or even unstructured active play may all help. The critical factor is movement, not perfection. As researchers continue to explore how lifestyle influences mental health, the message is simple and hopeful. Encouraging teens to move more can make a lasting difference in their lives.

Note: The article above provided above by The Brighter Side of News.

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