Muscle strength tied to biological age, study shows: Researchers say the study finding is some of the first evidence linking muscle weakness and biological age acceleration

Everyone ages at a different pace. That’s why two 50-year-olds, despite living the same number of years, may have different biological ages — meaning that a host of intrinsic and extrinsic factors have caused them to age at varying paces with different levels of risk for disease and early death.

Lifestyle choices, such as diet and smoking, and illness all contribute to accelerating biological age beyond one’s chronological age. In other words, your body is aging faster than expected. And for the first time, researchers have found that muscle weakness marked by grip strength, a proxy for overall strength capacity, is associated with accelerated biological age. Specifically, the weaker your grip strength, the older your biological age, according to results published in The Journal of Cachexia, Sarcopenia and Muscle.

Researchers at Michigan Medicine modeled the relationship between biological age and grip strength of 1,274 middle aged and older adults using three “age acceleration clocks” based on DNA methylation, a process that provides a molecular biomarker and estimator of the pace of aging. The clocks were originally modeled from various studies examining diabetes, cardiovascular disease, cancer, physical disability, Alzheimer’s disease, inflammation and early mortality.

Results reveal that both older men and women showed an association between lower grip strength and biological age acceleration across the DNA methylation clocks.

“We’ve known that muscular strength is a predictor of longevity, and that weakness is a powerful indicator of disease and mortality, but, for the first time, we have found strong evidence of a biological link between muscle weakness and actual acceleration in biological age,” said Mark Peterson, Ph.D., M.S., lead author of the study and associate professor of physical medicine and rehabilitation at University of Michigan.

“This suggests that if you maintain your muscle strength across the lifespan, you may be able to protect against many common age-related diseases. We know that smoking, for example, can be a powerful predictor of disease and mortality, but now we know that muscle weakness could be the new smoking.”

The real strength of this study was in the eight to 10 years of observation, in which lower grip strength predicted faster biological aging measured up to a decade later, said Jessica Faul, Ph.D., M.P.H., a co-author of the study and research associate professor at the U-M Institute for Social Research.

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