Depression is a growing public health concern, and exercise is an adjunctive treatment modality to improve depression, but the optimal form of exercise and the optimal dose are still unclear. This systematic review examined the efficacy of four major types of exercise (aerobic, resistance, mixed, and mind-body) on depression, as well as the dose-response relationship between total and specific exercise and depressive symptoms. We included randomized controlled trials that included participants aged 18 years or older with a diagnosis of major depressive disorder or a depressive symptom score above a threshold as determined by a validated screening measure, implemented one or more exercise therapy groups, and assessed depressive symptoms at baseline and follow-up. Forty-six studies (3164 patients) were included in the meta-analysis. Aerobic (standardised mean difference (SMD) = -0.93; 95% CI: -1.25 to -0.62) and mind-body exercise (SMD) = -0.81; 95% CI: -1.19 to -0.42) improved depressive symptoms better compared to controls, followed by mixed (SMD = -0.77; 95% CI: -1.20 to -0.34) and resistance exercise (SMD = -0.76; 95% CI: -1.24 to -0.28). This dose-response meta-analysis showed a U-shaped curve between exercise dose and depressive symptoms. The minimum effective dose was estimated to be 320 metabolic equivalent (METs) -min per week and the optimal response was 860 METs-min per week. These findings lead us to advocate that clinicians carefully select the appropriate dose of exercise based on the patient\'s individual characteristics and needs, in conjunction with psychological care interventions.

OBJECTIVE: To quantify the dose-response relationship between overall and specific exercise modalities and pain, in patients with nonspecific chronic low back pain (LBP). DESIGN: Systematic review with Bayesian network meta-analysis. LITERATURE SEARCH: We searched the Medline, Embase, Web of Science, Cochrane Library, Scopus, and SPORTDiscus databases from inception to June 2023. STUDY SELECTION CRITERIA: We included randomized controlled trials of exercise interventions in adults with nonspecific chronic LBP and at least 1 pain outcome reported at the main trial end point. DATA SYNTHESIS: A random-effects network meta-analysis was conducted. We assessed risk of bias using the Cochrane Risk of Bias Tool 2.0, and used the GRADE approach to judge the certainty of evidence for each outcome. RESULTS: Eighty-two trials were included (n = 5033 participants). We found a nonlinear dose-response relationship between total exercise and pain in patients with nonspecific chronic LBP. The maximum significant response was observed at 920 MET minutes (standardized mean difference = -1.74; 95% credible intervals: -2.43, -1.04). The minimal clinically important difference for achieving meaningful pain improvement was 520 MET minutes per week. The dose to achieve minimal clinically important difference varied by type of exercise; Pilates was the most effective. The certainty of the evidence was very low to moderate for all outcomes. CONCLUSION: The dose-response relationship of different exercise modalities to improve pain in patients with nonspecific chronic LBP had a U-shaped trajectory and low- to moderate-certainty evidence. The clinical effect was most pronounced with Pilates exercise. J Orthop Sports Phys Ther 2024;54(5):1-13. Epub 8 March 2024. doi:10.2519/jospt.2024.12153.