How fast can you run a mile?

Your answer may predict your risk of a heart attack or stroke in the next decade or so, according to two new studies.

UT Southwestern Medical Center researchers say that how fast a middle-age person can run a mile can help predict the risk of dying of heart attack or stroke decades later for men and could be an early indicator of cardiovascular disease for women.

The researchers analyzed the heart disease risk of 45 to 65 year-old men based on fitness levels and other traditional risk factors such as age, blood pressure, cholesterol and smoking habits.

They found that fitness levels among middleaged men show marked differences in risk for cardiovascular disease.

For instance, a 55-year-old man runs a mile in 15 minutes has a 30 percent lifetime risk of developing heart disease. In contrast, a 55-year-old who runs a mile in eight minutes has a lifetime risk of less than 10 percent.

“Heart disease tends to cluster at older ages, but if you want to prevent it, our research suggests that the prescription for prevention needs to occur earlier – when a person is in his 40s and 50s,” said Dr. Jarett Berry, assistant professor of internal medicine and a corresponding author on both studies.

According to the results, a high fitness level can lower the risk of heart disease even when other risk factors are present.

Heart disease is the number one cause of death in industrialized nations.  It is especially lethal for women, whose risk for heart disease is hard to assess and rises dramatically as they age.

The fitness test, researchers said, were particularly helpful in identifying women at risk for heart disease over the long term.

The studies mark the first time fitness levels have been used to attempt to predict risk for heart disease.

They were published in the Journal of the American College of Cardiology and Circulation.