At this month’s presidential debate, all eyes were on the candidates and how they interacted, right down to their handshake. It’s no surprise, because in the United States, people’s first impression is often the handshake. Firm, the thinking goes, relays confidence and strength.

Despite the cultural measurement of the handshake, your actual grip strength can mean much more than how confident you are. Grip strength, as it turns out, can serve as a reliable measurement of overall health – even as an indicator of the potential health of your heart and blood vessels. A strong grip matters more than just appearances. “Our grip strength is a big indicator of health,” said Milica McDowell, a Montana-based doctor of physical therapy and founder of Clearwater Physical Therapy in Bozeman. “It tells us about muscular endurance, power, and bone health in the upper extremities.”

It can also inform on all-cause mortality and cardiovascular mortality. As surprising as it may be, research shows a link between grip strength and how well and long you may live. “We found that muscle strength is a reflection of muscular frailty, and also vascular frailty,” said Darryl Leong, PhD, an associate professor and lead researcher at the Population Health Research Institute at McMaster University in Ontario, Canada. “Grip strength is a good indicator of muscle health.”

Grip strength is also easy to measure, whether in a formal setting like a doctor’s office or subjectively. If you struggle to open a jar of pickles, for instance, or if walking and steadily carrying your coffee cup from the kitchen to the table is a challenge, you may be more likely to have issues with your heart and blood vessels or other illnesses. But frailty – as indicated by a weak grip strength – isn’t unavoidable. There are several steps you can take to keep your handshake firm and confident, boosting your health along with it.

In his research into grip strength, Leong and his team considered that in about 25% of cases, doctors are uncertain of the cause of issues with the heart and blood vessels, or cardiovascular disease. Leong set out to identify new potential factors, grip strength chief among them. “Muscles and tissues deteriorate over time, and so does our cardiovascular system,” said Leong.