Most people hear “firm handshake” and automatically think “business world.” A cursory search reveals articles with titles like “Seven Super-Revealing Things Your Handshake Said About You” (Forbes) and “How a Handshake Can Tell You Everything You Need to Know About a Person” (Inc).
Those in the know, however, understand what a handshake really reveals: Current health and vitality. The amount of force that can be generated by the hand is a valid proxy for total-body strength. And total-body strength is one key to healthy aging.
Grip-strength testing is easy, fast, and noninvasive. It can be monitored over time. All it requires is a handgrip dynamometer, a tool that may cost less than a stethoscope, and a chair.
“Many studies have looked at strength as a predictor of positive health and weakness as a predictor of negative health outcomes,” said Mark Peterson, PhD, an associate professor at the University of Michigan, Ann Arbor, who’s worked on dozens of those studies.
Among the health risks associated with low grip strength: type 2 diabetes, heart disease, cancer, dementia and Alzheimer’s disease, depression, functional disability, osteoporosis, and premature death from any cause.
The prognostic merits of grip strength have been documented across continents and cultures. Although most of those studies have focused on older adults, they aren’t the only age group researchers have looked at.
“We have several papers on the value of grip strength for predicting diabetes and cardiovascular disease in children and adolescents,” Dr. Peterson said.
Survival of the strongest
The first thing to understand about grip-strength testing is that it’s only partially about grip. It’s mostly about strength. That’s what attracted Dr. Peterson to this line of research.
“I’m a former strength coach, so I wanted to make a case for why strength was important across populations, not just athletes,” he said. “I strongly believe in strength preservation and healthy living as a predictor for longevity.”
Consider a classic study of Swedish army recruits. Because of Sweden’s post–World War II conscription policy, virtually every young male in the country underwent a physical examination to see if they were fit for military service – an exam that included a grip-strength test.
That gave the researchers a database with more than a million participants. They followed up on them decades later through publicly available records.
What they found: The men with the weakest grip strength in their late teens were 20% more likely to have died by their mid-50s, compared with those with moderate to high grip strength. Even suicide rates were 20%-30% higher for the weakest recruits.
There’s a brutal Darwinian logic to the idea that a stronger person with a more powerful grip would enjoy a longer, healthier life. To our ancient ancestors, stronger hands meant they were probably better at everything that aided survival: hunting, fighting, building shelter, as well as bearing, transporting, and rearing children.
Fast forward to the 21st century where we must force ourselves to engage in physical activity. The old rules still apply: Strength aids survival.