Remember those old-time carnival games that tested the strength of your hand grip?
It turns out that a very similar test can also predict someone’s risk for heart attack, stroke and a shorter life, according to a recently published study in the health journal The Lancet. The hand grip test is cheap, easy and out-performs some traditional methods for predicting one’s risk of death by cardiovascular disease, according to lead researcher Dr. Darryl Leong of McMaster University in Canada.
The study is noteworthy because it tracked the health outcomes of almost 140,000 people across 17 economically diverse countries, which is by far the largest and most comprehensive analysis of the hand grip test’s ability to predict future mortality, cardiovascular disease and stroke. Study participants first tested their grip strength with a device called a dynamometer, and then researchers followed up with them after an average of four years to see how they were doing in terms of health.
Leong found that every five-kilogram reduction in grip strength (about 11 pounds) from the average was linked to a 16 percent increased risk of death, a 17 percent increased risk of cardiovascular death, a 9 percent increase in stroke and a 7 percent increase in heart attack.
These findings held even as researchers accounted for factors that could potentially be skewing the results, including differences in age, sex, education level, diet, exercise, prior disease and body mass index, to name a few.
More crucially, the handgrip test was better able to predict a person’s risk certain outcomes than the more traditional means of doing so -- that is, measuring systolic blood pressure or inquiring about physical activity levels.
"Grip strength was better than blood pressure and activity levels at predicting death," explained Leong in an email to HuffPost. "It was as good as blood pressure and better than activity levels at predicting death from heart disease or stroke, and it was not as good as blood pressure, but better than activity levels at predicting heart disease and stroke (including non-fatal heart disease ad stroke)."
The research hints at the important role muscle tone and strength play in maintaining a healthy lifestyle, and not just because more muscle strength means less physical disability, wrote Professor Avan Aihie Sayer of the University of Southampton in a commentary that accompanied Leong’s study. However, Leong’s population-based study wasn’t able to provide any explanation for the link between the two because of the limitations of this kind of association research.
"Poor muscle strength has been proposed to directly affect mortality through its association with increased disability,” wrote Sayer. "However, the findings from [the study] suggest that associations with cardiovascular disease and its risk factors might be an additional pathway.”
In other words, Sayer explained, the link between muscle strength and heart health suggests some kind of “mechanistic explanation” for how one lifts the other, but no one has yet uncovered it.
Currently, the hand grip test is not standard in clinical exams, but Leong thinks that the cheap, simple hand grip test can be especially useful to assess risk of death in people with pneumonia, cancer or heart disease, as his study found that low grip strength in these patients was linked to a high risk of dying from their disease, but high grip strength indicated a better outcome.
"We also expect it may be a useful test in low-resource settings, where access to more sophisticated tests is limited," Leong concluded. "One of the challenges in knowing where to use it lies in not knowing what we can do to improve it, so we really need to undertake more research."
Muscle strength has been linked to early death and sickness in past studies, but it’s unclear whether strengthening one’s muscles can lead to a decrease in the risk for cardiovascular disease, or whether muscular strength indicates physical fitness and thus a healthy heart. Further research is needed to confirm this cause-and-effect relationship, concluded Leong.
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