Curious about your risk of dying over the next decade? A simple treadmill performance test appears to be a good indicator of your odds. Researchers from Johns Hopkins Medicine have come up with a formula that predicts survival using stress test results.
“We’ve always known that fitness is connected to overall health and well being; what we didn’t know was exactly which exercise parameters are most predictive of long-term survival,” says lead investigator Haitham Ahmed, M.D. M.P.H., a cardiology fellow at the Johns Hopkins University School of Medicine.
Ahmed and his team sorted through data from 58,000 patients who’d undergone heart stress tests. From there, they developed a formula to predict the risk of dying over a 10-year period. The ability to exercise at an increasing speed and incline was particularly important in determining the formula. This ability was gauged with what’s known as METs, or metabolic equivalents. This essentially measures the amount of energy someone expends during the test.
“We saw that by far and large, the most important parameter was METS, which is an indicator of fitness,” says Ahmed. “After age, gender, METS, and then the percent of your maximum predicted heart rate – with just those four variables alone – we were able to predict survival better than anything else.”
According to Ahmed, these variables were used to construct an easy-to-interpret formula. In fact, anyone who gets a stress test can get the necessary information and plug it into the formula to arrive a number ranging from minus 200 to 200.
“We saw that if you had a score that was zero or above, you had a 97 percent chance or higher of survival at 10 years, which is outstanding,” says Ahmed. “If you were above 100, then you had a 98 percent survival. If you were above zero, then you had an 87 percent survival.”
People who landed in between zero and minus 100 were found to have an 89 percent survival rate. However, the numbers were much different for people who scored less than minus 100, which Ahmed says is hard to do. “Survival was in the 60s or so, maybe even lower,” he says. “But if you had a positive score, then your chances of survival over the next 10 years is very, very good.”