Strength training has a moderate antidepressant effect

A recent study published in Psychiatry Research provides evidence in favor of strength training as a potential complementary strategy to combat depression. This research, a meta-analysis of 38 previous studies, demonstrates that strength training can moderately reduce symptoms of depression. The analysis also highlights how the duration of the intervention, weekly frequency, and specifics such as the number of sets and repetitions can influence this antidepressant effect.

Depression, a condition that affected roughly 280 million people globally in 2019, is a leading cause of disability worldwide. Despite the widespread use of medications like selective serotonin reuptake inhibitors (SSRIs) and psychotherapy, a significant portion of those affected don’t fully recover, highlighting a critical need for complementary treatment strategies.

Among these, exercise, including strength training, has shown promise in reducing depressive symptoms. However, previous research had not fully explored how different aspects of strength training contribute to its antidepressant effects. This gap in knowledge led researchers to conduct a detailed analysis, aiming to refine exercise prescriptions for individuals with depression.

Senior author Lucas Melo Neves explained that his PhD research had focused on the intersection of exercise and brain health. In 2020, he embarked on a postdoctoral journey at the University of São Paulo’s Psychiatry Institute, where he sought to delve deeper into the nuances of how exercise influences mental health.

For their meta-analysis, the researcher conducted a comprehensive search across multiple online databases, aiming to capture experimental studies that investigated the relationship between strength training and depression outcomes. The selection criteria for studies were carefully defined to focus on an adult population diagnosed with major depression or experiencing subthreshold depressive symptoms, explicitly excluding those with other severe illnesses. This approach aimed to isolate the effects of strength training on depressive symptoms.

Initially, over two thousand articles were identified, but through a process of elimination based on titles, abstracts, and full-text assessments, the final analysis included 38 studies. These studies comprised a diverse sample of 2439 participants.

The meta-analysis showed moderate, significant improvement in depressive symptoms among participants who engaged in strength training compared to those in the non-active control groups. The researchers also discovered that the duration of the intervention, the weekly frequency of the training sessions, and the specific parameters of the training sessions (such as the number of sets and repetitions) played significant roles in the magnitude of the antidepressant effects.

Specifically, longer intervention durations, higher weekly frequencies, and greater numbers of sets and repetitions were associated with stronger antidepressant outcomes. This detail is crucial for practitioners and individuals alike, suggesting that not just any strength training regimen will do; the specific design of the program significantly impacts its effectiveness in alleviating depressive symptoms.

“The form of conducting the strength exercise is important,” Neves told PsyPost. “In other words, some characteristics of a program of strength exercises can potentialize have an antidepressant effect. Thus, doing strength exercises three times or more per week produces more antidepressive effects than doing exercises one or two times, and doing strength exercises with three or more sets of exercises produces more antidepressant effects compared to one or two sets.”

Interestingly, the researchers also explored differences in the antidepressant effects of isolated strength training versus strength training combined with other forms of exercise, such as aerobic training. While strength training alone showed a moderate and significant effect, the combination of strength training with other exercises did not significantly alter the outcome.

While the study provides compelling evidence supporting the antidepressant benefits of strength training, the authors acknowledge certain limitations. For instance, the analysis did not account for potential variables that could also influence outcomes.

“In our study, there was no comparison according to medication use, diet, and adherence, and some studies did not provide details about their training protocol,” Neves explained. “Furthermore, only two studies examined the effect of strength training plus aerobic training, which could impair the potential differences from the control.”

The study, “Strength training has antidepressant effects in people with depression or depressive symptoms but no other severe diseases: A systematic review with meta-analysis,” was authored by Fabricio Eduardo Rossi, Gustavo Gusmão dos Santos, Priscila Almeida Queiroz Rossi, Brendon Stubbs, Felipe Barreto Schuch, and Lucas Melo Neves.