Gut microbiota composition and long-term physical activity in healthy older adults at high and low performance levels

Aging is associated with significant alterations in the composition of the gut microbiota, including decreased microbial diversity. These changes are accelerated by lifestyle factors, such as sedentary behavior, which tends to increase with age. Although the role of physical activity in preventing age-related functional decline has been widely recognized in recent years, its long-term influence at different intensity levels on gut microbial composition in older adults remains unclear. In this study, we performed a cross-sectional analysis at 48 months, comparing gut microbiota profiles of older adults (71-84 years), stratified into high-performance (HP) and low-performance (LP) physical activity groups, with age-matched physically inactive controls. Following stool sample collection and microbiota profiling, physically active older adults showed significantly higher gut microbial diversity and distinct community structure compared with the controls. HP and LP groups shared similar gut microbial profiles, characterized by an enrichment of short-chain fatty acid (SCFA)-producing species, including Phocaeicola vulgatus, Dorea longicatena, Bacteroides uniformis, Alistipes putredinis, Blautia luti, and Oscillibacter ruminantium. However, specific taxa such as Turicibacter sanguinis and Eubacterium oxidoreducens, linked to serotonin signaling and acetate/butyrate production, were enriched in HP participants. Nevertheless, our findings suggest that long-term engagement in physical activity at both high and low performance levels may enhance gut microbiota composition in older adults.