Meta-analysis of 15 studies on depression suggests significant mental health benefits from being physically active

Is exercise really that important to individual’s mental health? A new study published in JAMA Psychiatry suggests that exercise is related to lower levels of depression, even for people who are doing less physical activity than is recommended by public health professionals.

Depression is a common and often debilitating mental illness that can lead to a myriad of negative outcomes, including isolation and even suicide. There are many factors that can influence an individual developing depression. Additionally, there are many different interventions that have been found to be effective in treating or preventing depression. There has been past research that suggests that physical activity can be a preventative measure for depressive symptoms.

Matthew Pearce and colleagues conducted a meta-analysis to study the association between physical exercise and depression. The samples used were adults who reported an element of physical activity and risk factors for depression. Studies were pulled from multiple online sources. Data was extracted from the studies, including volume of physical activity, depression cases, participant number, and follow-up.

This study utilized 348 full-text articles and their data. Countries included the United States, Australia, Japan, India, Ghana, Mexico, and Russia. Results showed that the biggest benefits in participants depression were when moving from no physical activity to some physical activity, rather than from low exercise to high levels of exercise. Just 2.5 hours a week of brisk walking was related to 25% lower risk for depression.

This relationship is thought to be due to a few different mechanisms, including inflammatory responses to activity and long-term changes to the brain. Additionally, it has been suggested that it may be related to self-esteem and body image, which can help social interactions and coping skills.

Despite the benefits of this study, it also has its limitations. While meta-analysis is a great way of collecting a large amount of data from diverse sources, the measures were somewhat different for many of the studies, including type or level of physical activity and time for follow up. This makes the study lack some consistency. Additionally, this research could not rule out the possibility that depression affects physical activity, rather than vice versa.

Nevertheless, the findings indicate there is an important link between physical activity and reduced depression.

“This meta-analysis found an association between physical activity and incident depression,” the authors concluded. “This suggests substantial mental health benefits can be achieved at physical activity levels even below the public health recommendations, with additional benefit for meeting the minimum recommended target but limited extra benefit beyond that. Assuming causality, 1 in 9 cases of depression might have been prevented if everybody in the population was active at the level of current health recommendations.”

The study, “Association between Physical Activity and Risk of Depression“, was authored by Matthew Pearce, Leandro Garcia, Ali Abbas, Tessa Strain, Felipe Barreto Schuch, Rajna Golubic, Paul Kelly, Saad Khan, Mrudula Utukuri,Yvonne Laird, Alexander Mok, Andrea Smith, Marko Tainio, Søren Brage, and James Woodcock.

By Percy