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Simple squeeze test offers window into long-term health
A growing body of research suggests that the strength of a person's grip can predict risks ranging from early death to chronic disease, yet assessing it requires little more than a tennis ball.
Why grip strength matters
Joshua Davidson, a strength and conditioning researcher at the University of Derby, calls hand grip strength one of the most reliable markers of human health. Clinical trials typically measure it with a hand dynamometer, a device that records the force of a maximal squeeze. Several companies are now marketing at-home versions paired with mobile apps, but Davidson says a basic squeeze test using a tennis or stress ball can provide a useful estimate.
"Any object you can grasp and deform without pain works," he explains. "Squeeze it as hard as possible until your grip fatigues. Maintaining that squeeze for 15 to 30 seconds is a solid benchmark." Tracking the duration over time can reveal trends in muscle health.
Beyond jars and cans: grip as a health proxy
Mark Peterson, a professor of physical medicine and rehabilitation at the University of Michigan, notes that while weak grip strength may only make daily tasks like opening jars slightly harder, researchers increasingly view it as a stand-in for overall musculoskeletal strength. It can signal whether someone is active enough or at risk of frailty-a state of heightened vulnerability due to declining physiological health.
A landmark study of nearly 140,000 adults across high-, middle-, and low-income countries found that grip strength predicted premature death more accurately than blood pressure. Other research linked stronger grip in midlife to a higher likelihood of living past 100. In a 44-year follow-up study, centenarians were 2.5 times more likely to have had grip strength in the top third of their age group when tested between ages 56 and 68.
Muscle as a metabolic reservoir
Darryl Leong, an associate professor of medicine at McMaster University, explains that grip strength reflects a combination of nutrition, physical activity, and underlying illness. "That's why it correlates with so many health outcomes," he says. Studies show that scores below 25.5 kilograms for men and 18 kilograms for women indicate a heightened risk of sarcopenia-the progressive loss of muscle mass and function tied to reduced mobility, falls, and fractures in later life.
Guillaume Paré, a physician and professor at McMaster, adds that even a handshake can reveal potential sarcopenia. "Weak grips where fingers don't fully close or hand muscles appear wasted are red flags," he notes.
The connections extend beyond physical ability. Muscle acts as a metabolic buffer, absorbing excess blood glucose and helping prevent insulin resistance. Weaker grip strength has been linked to type 2 diabetes, lower bone density, malnutrition, cognitive decline, and depression.
Grip strength and biological age
A 2022 study led by Peterson analyzed the grip strength and DNA of 1,275 men and women. Those with lower scores showed signs of accelerated aging, including differences in DNA methylation-chemical tags that influence gene expression in response to factors like obesity, pollution, or social stress.
Paré views grip strength as a marker of disease resilience and recovery potential. Research in cancer patients shows that weaker grip correlates with cachexia-severe muscle and fat loss-and poorer survival outcomes. Peterson adds that lower grip strength increases the risk of dying from pneumonia, as strong respiratory muscles are crucial for clearing infections.
From teens to Olympians: grip strength across the lifespan
The implications aren't limited to older adults. Studies suggest that a population's average grip strength can predict its Olympic medal count. Meanwhile, teenagers with weaker grips-often linked to excessive screen time-may face earlier health challenges. "Low grip strength is associated with poor metabolic health even in young adults," Paré says.
How to improve grip strength
Davidson emphasizes that grip strength is trainable at any age. A simple starting point is the tennis ball test: progressively work toward squeezing at maximal effort for longer durations. General resistance exercises, such as wrist curls or bicep curls with household items like cans or kettlebells, also help. Leong recommends broader physical activity to boost overall muscle strength, which in turn improves grip.
For older adults, Leong suggests the timed get-up-and-go test: record how long it takes to rise from a chair, walk three meters, turn around, and sit back down. "This assesses lower limb strength and mobility, contributing to total muscle health," he says.
"We all need regular physical activity as we age. You can work out at home with minimal equipment-two to three sets of wrist curls with 10 to 20 reps is a great start."
Joshua Davidson, University of Derby
