Effects of different intensities of aerobic exercise on intestinal permeability and inflammatory response in older...

Age-related alterations in immune function and intestinal barrier regulation contribute to chronic low-grade inflammation and functional decline. Although aerobic exercise may influence both processes, evidence regarding the role of exercise intensity in older adults remains limited. This study investigated the effects of different aerobic exercise intensities on inflammatory markers and intestinal barrier integrity in older adults.

In this parallel randomized clinical trial, 29 adults aged ≥60 years were assigned to high-intensity (n = 16) or low-intensity (n = 13) aerobic exercise for 12 weeks. Serum zonulin was the primary outcome and cytokines were secondary outcomes. Data were analyzed using mixed models for repeated measures, with FDR adjustment for secondary outcomes.

A significant group × time interaction was observed for serum zonulin, with a greater increase in the high-intensity group than in the low-intensity group (ΔΔ = 21.98 ng/mL; p = 0.017). No significant group × time interactions were detected for inflammatory or anti-inflammatory cytokines after FDR correction (all q ≥ 0.066). Although IFN-γ showed a greater proportional reduction following high-intensity exercise (p = 0.011), this effect did not remain significant after adjustment for multiple comparisons (q = 0.066). Exercise intensity appeared to influence intestinal barrier-related responses more consistently than circulating inflammatory markers.

High-intensity aerobic exercise increased serum zonulin more than low-intensity exercise in older adults, suggesting differential effects on intestinal barrier-related responses. Although inflammatory markers tended to improve more with high-intensity exercise, these findings should be interpreted cautiously. Individualized exercise prescription may be needed when considering effects on intestinal barrier function in older adults.