Simple Fitness Tests Help Predict Heart Attack, Stroke

(A. Kotok)

Researchers at University of Texas Southwestern Medical Center in Dallas have found in separate studies that the time it takes for a middle-age person 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 Southwestern researchers, plus colleagues from Stanford and Northwestern universities, and the Cooper Institute in Dallas, recently published their findings in the Journal of the American College of Cardiology and the journal Circulation (paid subscription required for both journals).

In the first study, the team analyzed the heart disease risk of men aged 45, 55, and 65 years old, based on their fitness level and traditional risk factors, such as age, systolic blood pressure, diabetes, total cholesterol and smoking habits. The scientists found that low levels of midlife fitness are associated with marked differences in the lifetime risk for heart disease.

A 55-year-old man who can run a mile in eight minutes, for example,  has a lifetime risk of less than 10 percent of developing heart disease. That risk expands to 30 percent if he needs 15 minutes to run a mile. Even for people with other risk factors, a higher fitness level lowered the lifetime risk of heart disease.

The second study that appeared in the journal Circulation showed that treadmill tests more accurately predict the likelihood of a person dying of heart disease or stroke than risk assessments based only on blood pressure and cholesterol levels.

Jarett Berry, who led the studies for Southwestern, says, “we found that low levels of fitness were particularly helpful in identifying women at risk for heart disease over the long term.” Women younger than 50 are particularly difficult to assess for long-term cardiovascular risk, he adds.

Researchers collected information for both studies from thousands of participants who underwent a comprehensive clinical exam and a treadmill exercise test at the Cooper Clinic in Dallas between 1970 and 2006. In the first study, researchers evaluated more than 11,000 men tested before 1990, focusing on fitness levels and traditional risk factors for heart disease. Of the 11,000 cases, 1,106 died of heart attack or stroke during the study period. In each age group — 45, 55, and 65 — higher levels of fitness were associated with lower levels of traditional risk factors.

In the second (Circulation) study, the team examined the records of 66,000 participants without cardiovascular disease, age 20 to 90, also at the Cooper Clinic in Dallas between 1970 and 2006. The researchers then monitored these individuals until death — 1,621 cardiovascular deaths — or the end of the study period, as long as 36 years. The team found that adding fitness to the traditional risk factors, significantly improves the ability to classify participants’ 10-year and 25-years risk of  death from cardiovascular disease.

Read more: Heart Disease Treatment Cost Expected to Triple by 2030

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