Exercise intensity as a modulator of gut microbiota and host metabolic health in obesity

(F). Mechanistically, intensity-dependent alterations in microbial communities may influence obesity-related pathways through modulation of short-chain fatty acid (SCFA) and bile acid metabolism, gut barrier integrity, endotoxemia, and inflammatory signaling. HIIT and MIT are linked to improved expression of tight junction proteins (ZO-1, Claudin, Occludin), reducing circulating lipopolysaccharide (LPS), and increasing SCFA-producing taxa; thus, supporting a role for the gut microbiome in mediating exercise-induced metabolic benefits. However, inconsistent findings between species, interindividual variability, and considerable heterogeneity in exercise intervention duration across both animal (4-16 weeks) and human (3-12 weeks) studies, as well as limited longitudinal human studies, underscore the need for deeper mechanistic investigations. Future research should employ metagenomic and metatranscriptomic profiling, integrate sex- and diet-stratified longitudinal designs, and clarify causal links between exercise-responsive taxa, microbial metabolites, and host physiology. Collectively, these data highlight exercise intensity as a key determinant of gut microbiome dynamics and reinforce the need for integrative, translational approaches to define its therapeutic potential for obesity and metabolic disorders.