Optimising exercise intensity for gut health: Effect on microbiota composition, barrier integrity and inflammation in...

Exercise influences gut microbiota composition and intestinal permeability, but the optimal intensity for maintaining gut health remains unclear. This study investigates the effects of different exercise intensities on abundance of some gut microbiota, epithelial barrier integrity and inflammatory markers. Male Wistar rats were randomly assigned to control (n = 5), low-intensity (10 m/min, n = 5), moderate-intensity (20 m/min, n = 5) and high-intensity (30 m/min, n = 5) exercise groups, exercising five times per week for 8 weeks. The relative abundance of Akkermansia muciniphila, Faecalibacterium prausnitzii and Escherichia coli was quantified using qPCR, whilst mRNA levels of zonula occludens-1 (ZO-1) and interleukin-6 (IL-6) were assessed as markers of barrier function and inflammation. A. muciniphila and F. prausnitzii abundance increased at moderate exercise intensity (P < 0.005), but decreased at high intensity (P = 0.0019), whereas E. coli rose sharply at high intensity (P < 0.001). ZO-1 expression was higher at moderate (β = 0.30, 95% CI 0.195-0.405, P < 0.001) and high intensity (β = 0.60, 0.495-0.705, P < 0.001), but not at low intensity (β = 0.10, -0.005-0.205, P > 0.05). IL-6 increases similarly (moderate β = 0.50, 0.247-0.753, high β = 1.10, 0.847-1.353, both P < 0.001). In conclusion, moderate-intensity exercise enhanced beneficial microbiota and epithelial barrier integrity, whereas high-intensity exercise promoted E. coli proliferation and IL-6-mediated inflammation, underscoring a dose-dependent, bidirectional regulation of the gut epithelial interface.