Impact of physical activity level on adult gut microbiome composition and metabolic function

Background Physical activity has been linked to improvements in metabolic health and gut microbiota composition. However, evidence connecting physical activity level (PAL) with the microbial metabolic potential in adults remains limited, particularly in South American populations. Methods We employed Gut Metabolic Modules (GMM) functional inference on 16S V4 rRNA data to elucidate how PAL shapes the gut microbiota’s metabolic potential in 233 Chilean adults. PAL was assessed via the self-reported IPAQ-SF questionnaire and categorized into low, medium, and high levels. Stratification by body mass index (BMI) and evaluation of physical activity volume (PAV) were also performed. Results No significant differences in overall microbial diversity were observed by PAL alone; however, when stratified by BMI, PAL was associated with shifts in the relative abundance of bacterial genera including Dorea , Holdemanella and Parabacteroides . Functionally, we identified 39 GMMs (37.8% of those evaluated) across the cohort, of which 18 modules differed by PAL, particularly protein and carbohydrate degradation pathways. PAV was positively associated with GMMs linked to energy metabolism, notably butyrate and propionate production. Conclusions PAL, especially when considered alongside BMI and activity volume, modulates the gut microbiome’s metabolic potential. As the largest Chilean cohort to apply 16S based functional profiling, this study provides foundational evidence from Latin America, highlighting physical activity as a modifiable factor for shaping microbiota functionality and host metabolic health.