Trained muscles age differently at the molecular level

Researchers analysed skeletal muscle tissue from people of different ages and fitness levels, examining proteins, genes and other molecular features simultaneously (an approach called multi-omics). Older adults who trained regularly showed about 50% fewer age-related molecular differences compared to sedentary peers. The findings appear in the study published in Nature Aging.

Energy factories stay switched on

One of the most striking findings concerns energy metabolism. In well-trained older adults, genes involved in cellular respiration and energy production by mitochondria (the cell’s energy generators) remained active. In less active peers, those same genes had become quieter with age. This suggests that regular exercise may help muscle cells maintain their energy systems for longer.

Trained older adults also showed stronger molecular responses to a single bout of exercise. Their cells appeared more reactive in terms of repair and adaptation processes. This difference in responsiveness was smaller in sedentary individuals. The researchers suggest that training leaves a kind of molecular memory in muscle cells, keeping them more responsive to physical stimuli.

What this means for healthy ageing

This research gives molecular weight to something many people already suspect: that exercise shapes how you age. It remains an association study; whether training directly causes the molecular profiles observed requires further research. From a longevity perspective, it is noteworthy that the effects extend beyond muscle strength and are visible in the deep molecular structure of the cells themselves.

How much exercise is needed to achieve these effects, and whether they emerge in people who only start training later in life, remains unclear. The study does not recommend a specific exercise regimen.

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