Narrative review: proposed exercise–gut–muscle axis and physical frailty
This narrative review links age-related gut microbiota changes, microbial metabolites and skeletal muscle physiology, and proposes an 'exercise–gut–muscle axis' as a framework connecting physical activity, the gut microbiome, skeletal muscle and frailty trajectories. Exercise effects on the microbiome were described as inconsistent. [1]
Automatic summary · not editorially reviewed
The key findings
The review states that physical frailty has become more prevalent as populations age and describes it as a geriatric syndrome with declining physiological reserve and physical function. [1]
According to the review, exercise may modify gut microbiota composition and metabolic function in some studies, but findings remain inconsistent. [1]
The authors propose the 'exercise–gut–muscle axis' as a framework linking physical activity, the gut microbiome, skeletal muscle and physical frailty trajectories. [1]
The source at a glance
- Study type / format
- Narrative review (abstract only)
- Population / context
- Older adults with or at risk of physical frailty, as discussed in the review
- Summary based on
- Study abstract
- Original publication
- September 23, 2026
Frailty, muscle decline and exercise in older adults
The review states that physical frailty has become more common as populations age. It describes frailty as a geriatric syndrome marked by declining physiological reserve and physical function, with a high risk of adverse health outcomes. Skeletal muscle dysfunction — reduced muscle mass, strength and metabolic capacity — strongly influences frailty development, according to the review. Exercise is presented as the most effective approach for maintaining muscle function and preventing functional decline in older adults, but the biological mechanisms behind its role in aging remain unclear.
Supporting source [1]
Gut metabolites and inconsistent exercise effects
The review notes that the gut microbiota produces various bioactive metabolites affecting metabolic regulation, immune responses and inflammatory pathways. In some studies, exercise may modify the composition and metabolic function of the gut microbiota, but the findings remain inconsistent. These exercise-associated alterations may influence production of microbial metabolites that may affect skeletal muscle metabolism. The review frames these interactions as the proposed 'exercise–gut–muscle axis', linking physical activity, the gut microbiome, skeletal muscle and physical frailty trajectories.
Supporting source [1]
Narrative synthesis aims to set research priorities
The authors describe their work as a narrative synthesis integrating emerging evidence on exercise–microbiome–muscle interactions. They suggest it may help identify priorities for future research on lifestyle-based strategies that support healthy aging and may help delay physical frailty in older adults. Because this is a narrative review, the proposed axis is a framework for future research rather than a validated mechanism or a tested intervention.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. This is a narrative review, so the proposed axis is a framework, not a validated mechanism or tested intervention. Exercise–microbiome findings are described as inconsistent, and the abstract reports no sample, follow-up or outcome data.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Morishita S, Iida N, Sato T, Endo Y, Tanno D, Yabuki S. · europepmc.org · September 23, 2026