Meta-analysis on the chronic effects of exercise on depression in older adults

Introduction This review aimed to investigate the effects of chronic exercise on depression severity and various depressive symptoms in Randomized Controlled Trials (RCTs) including older adults with an average age of at least 60 years and a minimum level of mild depression. Thereby, the moderating effects of various intervention and individual characteristics were considered. Methods We searched Web of Science, Academic Search Complete, MEDLINE, CINAHL, APA Psycinfo, SPORTDiscuss, and Cochrane from inception until July 2023. Primary outcomes targeted changes in overall depression severity assessed with validated depression scales; secondary outcomes included changes in specific symptoms that are related to depression such as sleep quality, fatigue, anxiety, mood, apathy, weight changes, processing speed, and executive functions. These were measured from baseline until the end of the intervention. Meta-analysis was undertaken to synthesize the effects of chronic exercise on primary and secondary outcomes. The moderating effects of intervention and individual characteristics were investigated by subgroup-analyses and meta-regression. Publication bias was addressed through sensitivity analyses. The quality and certainty of the evidence were assessed using GRADE and RoB 2. Results The comprehensive search yielded 20,700 records, of which 145 peer-reviewed articles including 187 effect sizes met the inclusion criteria. We found that chronic exercise significantly improved overall depression severity (g = -0.68, p < .001, k = 187) as well as depressive symptoms related to anxiety (g = -0.56, p < .001, k = 24), BMI (g = -0.26, p = .005, k = 13), executive functions (g = -0.33, p = .004, k = 18), sleep (g = -0.47, p < .001, k = 14), and processing speed (g = -0.35, p = .015, k = 11). Regarding exercise characteristics, effects were particularly strong for interventions that included exergames, had a long duration, and involved high cognitive demand. Additionally, effects increased with advancing age and higher baseline depression severity. Egger’s test and an asymmetrical funnel plot suggest the presence of publication bias. Discussion/Conclusion This study is up to date the most extensive review on chronic exercise effects on depression in older adults. The results highlight the importance of individualizing exercise regimens to achieve optimal outcomes. The conclusions drawn may provide a foundation for developing evidence-based recommendations for exercise programs aimed at alleviating depression in older adults.