The Norwegian study shows youth

The Norwegian study shows youth

New research that has followed Norwegian teens for over a decade shows that getting more active in your teens can significantly reduce your risk of depression and reveals the real power of exercise for mental health.

A research team from the Norwegian University of Science and Technology followed a large group of children and adolescents between the ages of 6 and 18 and found that young adolescents who increase their physical activity starting at age 14 have a lower risk of developing depression later in life. The study is published in theJournal of the American Academy of Child & Adolescent Psychiatry.

background

A significant increase in the prevalence of major depressive disorder among young people has been observed over the last decade. The transition period from childhood to adolescence is particularly sensitive to the development of mental disorders, including depression.

Physical activity is a promising preventive intervention for mental health and overall well-being. However, increasing physical activity as an intervention to prevent depression in children and adolescents has shown only a modest short-term effect. This highlights the need for more research with a longer follow-up period.

The majority of observational studies aim to understand whether a child with higher levels of physical activity has less depression than other children with lower levels of physical activity. However, this type of cross-sectional (“between-person”) analysis cannot accurately assess the risk of depression.

Longitudinal comparisons, which compare changes in an individual over time (within-person comparison), provide more accurate information for planning treatment or developing a preventative intervention.

Given the significant impact of physical activity on mental health, researchers designed this study to examine the relationships between physical activity, sedentary time, and depressive symptoms. They included sedentary time in the analysis because it is an essential parameter for predicting health, independent of physical activity. By using within-person analyzes in this study, researchers controlled for any stable, unmeasured confounding factors, providing more robust findings than traditional between-person comparisons.

Study design

The study analyzed data from 873 participants in the Trondheim Early Secure Study, a cohort study of children born in 2003 and 2004 in Trondheim, Norway. Participants were followed from ages 6 to 18.

Participants' physical activity was assessed every two years using an accelerometer, and clinical interviews were conducted to determine their mental health. The study analyzed seven rounds of data (6, 8, 10, 12, 14, 16, 18 years) collected by them.

"We also examined whether beliefs in one's physical abilities, body image and sports participation have an influence on the association between physical activity and depression," said Professor Silje Steinsbekk, Department of Psychology at the Norwegian University of Science and Technology.

Study results

The study found that adolescents ages 14 to 18 (middle to late adolescence) with lower levels of physical activity had a higher risk of developing depressive symptoms two years later. This association was similar for male and female participants.

However, the study failed to find a link between sedentary time and depressive symptoms. Regarding the opposite direction of influence, the study found that increased levels of depressive symptoms predicted decreased physical activity at ages 10 to 12 and 14 to 16.

Importantly, the study tested whether factors such as exercise self-esteem, body image, or sports participation explained the relationship between physical activity and depressive symptoms. However, the researchers found that none of these factors mediated the association.

Investigate significance

The study shows that young people who increase their physical activity levels starting at age 14 have a lower risk of developing depressive symptoms later in life. While protective status was only established from age 14 onwards, the difference in effect size compared to earlier ages was not statistically significant. However, a similar benefit from physical activity has not been observed in previous years.

“This finding applied to adolescents aged 14 to 16 and 16 to 18. Both the sum of daily physical activity and the proportion of activities that are more intense and particularly important for our health protect against symptoms of depression,” said Steinsbekk.

In younger age groups, the study finds that participants who have more depressive symptoms are more likely to have lower levels of physical activity.

"Although we found that physical activity in adolescence appeared to be protective against depression symptoms, this was not true for young adolescents aged 10 to 14. However, we found an opposite correlation from 10 to 12 and 14 to 16 years: those who had more symptoms of depression were more likely to engage in less physical activity."

The study failed to find a link between time spent in sedentary activity and the risk of depressive symptoms, highlighting that the measurement is not just the opposite of physical activity. Physical activity is associated with a sense of accomplishment, self-esteem, neurophysiological effects, social interactions, camaraderie, and belonging, which together contribute to an individual's physical and mental well-being.

As mentioned by researchers, these results cannot be generalized to clinical samples of adolescents with depression because the association between physical activity and depression is stronger in clinical samples. Similarly, these results may not be generalizable to other populations as the prevalence of mental health problems is lower in Norway and Norwegian children are reported to be more physically active than other European children.

It's also worth noting that the effects found in this study were moderate in size, and although they may accumulate over time, many factors influence whether young people develop depressive symptoms.

Overall, the study suggests that interventions aimed at increasing physical activity in young people may help prevent the development of depressive symptoms.

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