Exercise-driven microbiome changes regulate host immunity.

Exercise reshapes host physiology and immunity, yet the mechanisms linking physical activity to disease protection remain incompletely defined. Emerging evidence indicates that exercise remodels the gut microbiome, producing compositional and metabolic adaptations that can regulate immune function. In this Review, we discuss how exercise-responsive microbiota and microbial metabolites, including short-chain fatty acids, secondary bile acids, and the one-carbon metabolite formate, influence systemic inflammation, antitumor CD8 T-cell immunity, autoimmunity, and metabolic disease. Defining causal taxa, microbial metabolic pathways, and host-sensing mechanisms may enable microbiome-informed exercise prescriptions and targeted metabolite-, probiotic-, or postbiotic-based therapies.