Major depressive disorder (MDD) is a prevalent mental illness characterised by persistent sadness, loss of interest in activities and cognitive impairment. While pharmacological and psychotherapeutic treatments remain the standard for MDD management, non-pharmacological interventions, such as aerobic exercise, have gained attention for their potential benefits in reducing depressive symptoms and improving quality of life. Although several studies have explored the effectiveness of aerobic exercise in managing MDD, there is still no comprehensive synthesis of the existing evidence. This study aims to synthesise existing evidence on the effects of aerobic exercise interventions in the management of individuals diagnosed with MDD.

The systematic review will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) guidelines. A comprehensive search will be conducted across Cochrane, Medline, PEDro, CINAHL, Scopus, Web of Science and BioMed Central databases. Search terms will be developed using the Population, Intervention, Comparison, Outcome and Study design (PICOS) framework, incorporating keywords and Medical Subject Headings related to ‘Major Depressive Disorder’, ‘Aerobic Exercise’, ‘Depression’, and ‘Quality of Life’. Only intervention studies, including randomised controlled trials, quasi-experimental and pre–post intervention studies, will be included involving adults aged 18 years or older diagnosed with MDD according to standardised criteria (eg, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and International Statistical Classification of Diseases and Related Health Problems -10 (ICD-10)). For included intervention studies, the comparator will be standard care, placebo or no-exercise control groups. The primary outcome is change in depressive symptoms, and secondary outcomes include quality of life, anxiety and stress-related biomarkers. Three independent reviewers will screen studies, extract data using Covidence software (Veritas Health Innovation in partnership with Cochrane) and assess study quality using the updated Cochrane Risk of Bias 2.0 (Rob-2) tool alongside the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. If feasible, a meta-analysis will be conducted using RevMan V.5.4 (Cochrane's Review Manager), with effect sizes determined by mean differences, standardised mean differences or ORs, depending on the outcome type. This study is currently at the proposal stage, with article searches expected to begin in November 2025 and data extraction anticipated to be completed by January 2026.

No ethical approval is required as this review uses existing published data. Findings will be disseminated through a peer-reviewed journal and presented at academic conferences.

CRD420251151897.