Summary:
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterised by insulin resistance and impaired pancreatic β-cell function, driven by genetic, environmental, and inflammatory factors. Increasing evidence indicates that the gut microbiota plays a significant role in T2DM pathogenesis, with affected individuals showing reduced levels of beneficial bacteria and increased levels of those linked to metabolic dysfunction. Regular exercise has also emerged as an important modulator of gut microbiota composition and function and may improve insulin sensitivity partly through microbiota-mediated mechanisms. This study is a narrative review that synthesised evidence from 58 peer-reviewed publications examining the relationships between exercise, gut microbiota, and metabolic outcomes in T2DM. The review included both human and animal studies and focused on the physiological mechanisms through which exercise-induced changes in gut microbiota may improve glycaemic control. Mechanisms examined included alterations in microbial diversity, reductions in toxin load, modulation of bile acid metabolism, changes in short-chain fatty acid production, and improvements in amino acid metabolism. The review also assessed whether these effects varied according to exercise type, intensity, and duration. The findings indicate that exercise is associated with favourable shifts in gut microbiota composition and metabolic activity, which are linked to improvements in insulin sensitivity and overall metabolic regulation in T2DM. Although the specific microbial responses differ across exercise modalities, the collective evidence supports exercise as a key strategy for improving T2DM outcomes partly via gut microbiota-mediated pathways.
Abstract:
Background: The gut microbiota is increasingly recognized as a key factor in the pathogenesis of type 2 diabetes mellitus (T2DM). Concurrently, exercise intervention has emerged as a promising non-pharmacological strategy for T2DM management, potentially mediated through gut microbiome modulation.
Methods: This narrative review searched Web of Science, PubMed, and Embase for literature published from 1992 to the present, ultimately including 58 relevant publications. The focus was on elucidating the physiological mechanisms by which exercise modulates gut microbiota to ameliorate T2DM.
Results: Our synthesis indicates that exercise training beneficially alters gut microbiota composition and function, which in turn enhances systemic insulin sensitivity and improves metabolic disturbances in T2DM. These improvements are mediated through multiple pathways, including bile acid metabolism, short-chain fatty acid production, lipopolysaccharide reduction, and branched chain amino acid catabolism. The effects of exercise on the gut microbiome are influenced by factors such as exercise intensity, duration, and type, suggesting the need for individualized regimens.
Conclusion: Exercise intervention improves T2DM by modulating gut microbiota via several mechanistic pathways. Future research should prioritize personalized exercise prescriptions, larger sample sizes, integrated multi-omics approaches, and exploration of combined interventions with diet or medication to optimize T2DM prevention and treatment.
Article Publication Date: 24/12/2025
DOI: 10.3389/fnut.2025.1682549
