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Research · Muscles & movement

Some muscle aging happens even in fit people

LongevityWatch editors · July 8, 2026 · 2 min

Exercise slows many aspects of muscle aging. But a new study shows that some molecular changes in muscle tissue occur regardless of fitness level. Not everything can be prevented.

It is well established that regular physical activity benefits muscle health in older age. The deeper question is: which age-related changes in muscle are actually modifiable through training, and which are not? A new study published in Nature Aging addresses this using a multiomics approach, a method that simultaneously measures multiple biological layers such as gene activity, proteins and metabolites, in human muscle tissue.

The researchers categorised age-related molecular changes into two groups. The first are ‘preventable’ alterations: patterns that in well-trained older adults still resemble those of younger people. The second are ‘unavoidable’ alterations: patterns that shift with age regardless of fitness level.

What exercise can and cannot do

Trained older adults retained more youthful molecular profiles across several dimensions. That is encouraging. But the study also shows that a portion of age-related transcriptomic changes, shifts in which genes are active, occurred even in physically fit individuals. In addition, trained older adults showed stronger biological stress responses to exercise, and this was associated with better health outcomes.

That last point is notable. The recovery response to exercise appears to become more robust with consistent training, suggesting that regular physical activity not only amplifies direct training benefits but also strengthens the body’s adaptive capacity at the cellular level.

What this means for muscle aging research

The findings are based on an observational design: participants were assessed at a single time point. Whether ‘preventable’ changes are truly caused by exercise, or simply more common in people who have been active throughout their lives, remains an open question.

For longevity science, the distinction between modifiable and non-modifiable aging is useful. It can help prioritise which biological processes are worth targeting in muscle preservation research, and which may require a different approach.

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