When she was a practicing occupational therapist, Elizabeth Fain started noticing something odd in her clinic: Her patients were weak. More specifically, their grip strengths, recorded via a hand-held dynamometer, were “not anywhere close to the norms” that had been established back in the 1980s.
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In a study published in 2015 in The Lancet, the health outcomes of nearly 140,000 people across 17 countries were tracked over four years, via a variety of measures—including grip strength. Grip strength was not only “inversely associated with all-cause mortality”—every 5 kilogram (kg) decrement in grip strength was associated with a 17 percent risk increase—but as the team, led by McMaster University professor of medicine Darryl Leong, noted: “Grip strength was a stronger predictor of all-cause and cardiovascular mortality than systolic blood pressure.”
Grip strength has even been found to be correlated more robustly with “ageing markers” than chronological aging itself. It has become a key method of diagnosing sarcopenia, the loss of muscle mass associated with aging. Low grip strength has been linked to longer hospital stays, and in a study of hospitalized cancer patients, it was linked to a “an approximate 3-fold decrease in probability of discharge alive.” In older subjects, lower grip strength has even been linked with declines in cognitive performance.
“I’ve seen people refer to it as a ‘will-to-live’ meter,” says Richard Bohannon, a professor of health studies at North Carolina’s Campbell University. Grip strength, he suggests, is not necessarily an overall indicator of health, nor is it causative—if you start building your grip strength now it does not ensure you will live longer—“but it is related to important things.” What’s more, it’s non-invasive, and inexpensive to measure. Bohannon notes that in his home-care practice, a grip strength test is now de rigueur. “I use it in basically all of my patients,” he says. “It gives you an overall sense of their status, and high grip strength is better than low grip strength.”
Curious about what that all of that means for my own grip strength, I went out and bought a Jamar Hydraulic Hand Dynamometer, which is favored by clinicians. My strength rang in at nearly 62 kgs which, according to a chart of normative grip strengths in the Jamar’s manual, was above the mean for males 45-49, but not hugely outside the standard deviation. In that data, my age group did worse than the 20-24 age group, like you’d expect.
What was surprising was that my grip strength came in at 40 percent above a group of contemporary male college students that Fain measured last year. She found that a group of males aged 20-24—ages that had produced some of the peak mean grip strength scores in the 1980s tests—had a mean grip strength of just 44.7 kgs, well below my own and far below the same cohort in the 1980s, whose mean was in the low 50s. There were also significant declines in female grip strength.
Of course, if lots of people take to specifically training their grip strength, its correlation with overall health will decrease.
Modern society has less manual labor thus lower grip strength. Growing up most of us older people did manual work like push mowing, automotive repairs, construction as opposed to playing with keyboards and touch surfaces. The study if anything is a snapshot of the change in labor. As a health indicator the metrics will have to move the bell curve left to reflect the younger generation’s limp grip.
For grown men, this graph looks like a mortality graph, leading by 10 or 20 years. In women, it looks less so. That is, men start croaking at, what, 60 to 70? And this graph’s value takes a dive at 50. So grip strength predicts age, which predicts death.
Now, if you want to use grip strength to predict mortality, then you’d compare your subject to the grip strengths of his age-cohorts, not to age-cohorts of a few decades ago. Lifestyle changes, as Wang Wei Lin points out.
I wonder whether you could use some kind of small-motor-skill measure on women.
I wonder whether you could use some kind of get-out-of-chair measure on both sexes. Like how long it takes to get out of a chair, go around it, and sit down again. 3 times. Make the chair somewhat unstable. On rollers and leaning back, for instance. And the person in socks. On a slippery floor. … … … Um. 15 seconds.
I guess we’re in good shape now that three commenters have already, one way or another, highlighted the problem of correlation not equaling causation here.
It did make me want to go and get a dynamometer, though.
Less a marker of any individual’s mortality, and more just a marker of our slow transition into Eloi. Finally I’m a trend leader.
Climbers have intense grip strength and muscle density generally. Pass on the squeezey things; hang from a bar.
Early physical activity doesn’t just affect the muscles; it strongly influences bone characteristics as well. Unstructured childhood rough-and-tumble play being literally necessary for military-grade bone density is just the tip of the iceberg.
That the boys play Cowboys and Indians is a matter of national security.