Meeting WHO physical activity standards may promote greater gut microbiota diversity and preservation of Ruminococcus in community-dwelling older women.

Abstract

Background: Gut microbiota plays a crucial role not only in digestion but also in systemic physiological functions, including immune and neural regulation. High microbial diversity contributes to intestinal homeostasis, whereas reduced diversity has been associated with various diseases. Physical activity is reported to influence both the composition and function of gut microbiota; however, the impact of daily physical activity on gut microbiota in older adults remains poorly understood. This study exploratorily investigated the association between objectively measured daily physical activity and gut microbial diversity and composition in older women who are at increased risk of reduced physical activity and gut microbial dysbiosis.

Methods: A cross-sectional study assessed daily physical activity using an accelerometer-based activity monitor in 73 community-dwelling older women. We classified participants as meeting (n = 56) or not meeting (n = 17) the World Health Organization (WHO) physical activity guidelines. Fecal samples were collected and analyzed using 16S rRNA sequencing to evaluate gut microbial diversity and composition.

Results: Participants not meeting the WHO activity guidelines exhibited lower gut microbial diversity (Observed Features: 134 ± 23 vs. 161 ± 45, Chao1 index: 137 ± 24 vs. 167 ± 49, all p < 0.05) and distinct microbial community structures (weighted UniFrac distances, PERMANOVA, p < 0.05) as compared with those meeting the guidelines. In particular, the relative abundance of short-chain fatty acid-producing Ruminococcus was reduced in the less active group.

Conclusion: Habitual daily physical activity was associated with gut microbiota diversity and composition in older women in this exploratory study. In particular, the relative abundance of Ruminococcus may reflect differences in gut microbial function. Future longitudinal and interventional studies are needed to further clarify causal relationships and support the development of personalized strategies to promote gut health and healthy aging.