GRIP STRENGTH HANDY AS MEASURE OF AGING
Want to know how well you’re aging? Check your grip strength.
A recent study of 1,275 men and women found that those with relatively feeble handgrip strength, a reliable marker of overall muscle quality and strength, showed signs of accelerated aging of their DNA. Their genes appeared to be growing old faster than those of people with greater strength.
The study, although preliminary, raises the possibility that visiting the gym or doing a few pushups at home might help turn back the clock and make our cells and selves more biologically youthful.
People who lift weights are substantially less likely to develop heart disease, high blood pressure and many other chronic illnesses than those who skip resistance exercise.
Strength also can be an indicator of how long we’ll live. In a 2015 study of almost 140,000 adults in high-, middleand low-income nations, reduced handgrip strength was closely linked to mortality in people of all incomes, predicting risks for early death better than blood pressure, which is often considered one of the best indicators of life span.
How, though, might a sturdy grip today influence our well-being tomorrow?
“Grip strength is often called a biomarker of aging,” said Mark Peterson, an associate professor of physical medicine and rehabilitation at the University of Michigan in Ann Arbor, who led the new study. “But the biological context for why it’s so predictive of positive and negative outcomes during aging hasn’t really been clear.”
Maybe, Peterson and his colleagues speculated, epigenetics might be key. Epigenetics involves changes to the numbers and actions of certain tiny molecules that attach to the outer surface of a gene and affect how and when that gene turns on. Epigenetic changes occur in response to our diets, exercise habits and many other aspects of our lives, and affect our DNA and health. Epigenetics also may signal how rapidly we are aging, recent science shows.
About a decade ago, researchers began analyzing huge data sets of people’s epigenomes — the epigenetic changes unique to each of us — and developing “epigenetic clocks” that estimate our biological age. Chronological age is how old we are, according to our birth certificates. Biological age indicates the functional age and health of our cells and bodies. The two numbers can differ substantially.
Epigenetic clocks use algorithms to assess biological age, based on the various patterns of molecules on genes. If the clock suggests your biological age exceeds your chronological one, you’re aging faster than normal.
“Grip strength is often called a biomarker of aging.” Mark Peterson • associate professor of physical medicine and rehabilitation
Peterson and his colleagues wondered whether strength might be linked to epigenetic age. They began gathering records for 1,275 participants of an ongoing study of aging. The researchers then determined everyone’s approximate epigenetic age from their blood cells and checked death records for up to 10 years after people joined the study.
They found that, in general, the weaker someone’s grip strength was, the higher his or her epigenetic age, leaving them potentially more vulnerable to earlier illness or death.
Although the study shows that people with punier muscles have an elevated epigenetic age, it can’t prove that weakness directly caused the accelerated aging. Other lifestyle factors might be at play, such as income, diet or medical history.