Young women with heart disease may take a harder hit from mental stress compared with their male counterparts, a new study suggests.

The researchers said the effects of psychological stress, which don't show up on heart patients' regular medical tests, may partly explain why women with heart disease are more likely to die from heart attacks than are men with heart disease.

"There's a very interesting paradox concerning young women and chronic heart disease," said study researcher Dr. Viola Vaccarino, chairwoman of cardiovascular research and epidemiology at Emory University's School of Public Health in Atlanta, Georgia. "They have higher mortality and complication rates after heart attacks compared with men of the same age," despite having fewer risk factors for heart disease, she said. [11 Tips to Lower Stress]

In the study, 534 patients with coronary heart disease ages 38 to 79 underwent a mental stress test, as well as a conventional physical stress test, while their hearts were being monitored.

For the mental stress test, the researchers asked the patients to give a speech in front of a small group of people about a real-life event that they found stressful. On another day, the patients ran on a treadmill, which is a standard test for assessing the heart's health during physical stress.

The researchers looked at patients' hearts to measure any reduction in blood flow to the heart muscle itself, which is a common problem in people with heart disease, and which can lead to heart attacks.

The Heart scans showed "dramatic differences" between men and women during the mental stress test, particularly in younger people, Vaccarino said.

When under mental stress, women ages 55 and younger showed a reduction in blood flow to the heart that was three times that of men of the same age, according to the study.

The difference between men and women was smaller among people ages 56 to 64, but still women in that group showed a greater reduction in blood flow to the heart during mental stress compared with men of the same age.

There were no gender differences in patients 65 and older, the researchers found.

During the physical stress tests, however, men and women didn't show much difference in blood flow changes to the heart, according to the study, which was presented on Monday (Nov. 17) here at the meeting of the American Heart Association.

"Women who develop heart disease at a younger age make up a special, high-risk group because they are disproportionally vulnerable to emotional stress," Vaccarino said.

People in their late 30s, 40s and early 50s generally face considerable levels of stress in daily life as they manage working, raising children and sometimes caring for their parents, Vaccarino said. They are also vulnerable to the effects of depression on the heart's health, she said.

Physicians should be aware of the importance of psychological stress in young and middle-age women with heart disease, and "ask the questions about psychological stress that often don't get asked," Vaccarino said.

Women with high levels of stress could benefit from counseling, stress reduction techniques and getting more exercise, she said.

"Probably the most useful measure is to encourage patients to exercise regularly, because that's a measure that has been shown clearly to improve mental health and at the same time also physical health," Vaccarino said.

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