Doctors hesitate to give women stress tests to diagnose heart disease because the results can be misleading, but according to recent research, a woman's stamina on the treadmill can help gauge her risk. Stress tests detect abnormalities in some women that scientists believe are caused by hormonal differences between women and men, and are not necessarily a sign of heart disease.
Focusing on a woman's fitness during the treadmill test - how long she can exercise as her heart beats faster and the time it takes her heartbeat to return to normal after she stops - does predict her risk of dying from heart disease.
Researchers from the Johns Hopkins University in Baltimore, USA, did a 20-year follow up study of nearly 3,000 women who took treadmill tests in the 1970s. The women who performed below average were 3.5 times more likely to die of heart disease compared to those who performed better than average. Unreliable stress test results sometimes require women to undergo expensive follow up tests to see if their heart abnormalities are a sign of heart problems. Half of the women with perceived abnormalities on the stress test turn out not to have heart disease.
The researchers concluded that regular exercise was more important than losing weight, lowering blood pressure or reducing cholesterol levels in reducing a woman's risk of heart attack or stroke. Another study has found that exercise capacity is more accurate at predicting heart disease in women than in men.
JAMA, September 2003