Mechanisms by Which Exercise Alleviates Depressive Symptoms: The Potential Role of Short-Chain Fatty Acids

Short-chain fatty acids (SCFAs) are important metabolic products generated by the gut microbiota and they play a crucial role in maintaining intestinal barrier integrity, regulating immune responses, and participating in neural modulation. In recent years, accumulating evidence has indicated that dysregulated SCFA levels are closely associated with depressive states and the onset and progression of depression. SCFAs may be involved in the pathophysiology of depression through multiple pathways, including modulation of gut microbiota homeostasis, inflammatory responses, vagal nerve signaling, and 5-hydroxytryptamine (serotonin) metabolism. This review summarizes the roles of SCFAs in depressive states and depression, the regulatory effects of different exercise modalities on SCFA metabolism, and the potential mechanisms by which exercise-mediated SCFA modulation alleviates depressive symptoms, aiming to provide a theoretical basis for exercise-based interventions in depression.