Mental stress affects women's hearts more than men's

Researchers have known for decades that stress contributes to heart disease. But a new analysis by researchers at Duke Medicine shows mental stress may tax women's hearts more than men's.

The research appears online Oct. 13, 2014, in the Journal of the American College of Cardiology.

"Normally when under stress, we fight back or run away. In order to do that, we need to pump more blood to the body," said Wei Jiang, M.D., the study's senior author and professor of medicine, psychiatry and behavioral sciences at the Duke University School of Medicine. "According to the data, women were not reacting that way as well as men were."

In their analysis, Duke researchers reviewed data on 254 men and 56 women who had a history of ischemic heart disease or decreased blood flow to the heart. The group was part of a Duke study published in 2012 called REMIT, which evaluated the impact of an anti-depressant medicine to reduce stress-induced heart trouble.

Participants performed stressful tasks, such as describing an event that made them angry, while researchers monitored their heart function and other vital signs.

During times of stress, 57 percent of female participants experienced reduced blood flow to the heart, or ischemia, as compared to 41 percent of men. Ischemia is a prevalent component of cardiovascular disease and often the factor that leads to death.

Differences between the sexes could provide clues on how to tailor heart disease education, prevention and treatment for women and men. Heart disease kills about 600,000 people each year and remains the leading cause of death in the U.S. for both men and women, according to the Centers for Disease Control.

But studies have shown disparities in the outcomes of ischemic heart disease, with women faring worse than men. CDC surveys have found disparities in women's awareness of heart disease risks, and how quickly women seek treatment for their symptoms.

In the Duke study, women under mental stress expressed a greater increase in negative emotions and a greater decrease in positive feelings. By contrast, men had greater rise in blood pressure in response to mental stress, the data showed.

"Men may have been expressing less changes in emotions, but they had an obvious negative physiologic response to stress," said Zainab Samad, M.D., M.H.S., the study's lead author and assistant professor of medicine at Duke.

The data also found sex distinctions in blood platelet behavior. The aggregation of platelets can lead to a blockage that could cause a heart attack. Despite the use of medications designed to keep blood platelets from clustering together, the platelets of female participants under mental stress were still clumping to a greater extent than those of male participants.

Samad said that with further research, this detail could help tailor blood-thinning medications for more effective use in women.

"The impact of negative physiologic responses to mental stress needs to be recognized in cardiovascular risk assessment in both sexes," Samad said. "These differences may be potential reasons for differences in outcomes, and may also serve as avenues for further research. This could be a signal that we have been looking for to treat heart disease better, especially in women."