Mental stress is bad for everyone, but it might be worse for women. A new study suggests it could lead to increased heart problems.
The finding surprised the researchers, partly because men are more likely to succumb to cardiovascular disease at a younger age than women.
"It did catch us off guard," said the senior author, Chester Ray of Penn State College of Medicine in Hershey, Pa.
For the study, the researchers recruited nine men and eight women. The volunteers had their blood pressure and heart rate tested at rest. As well, an ultrasound device measured the amount of blood flowing through the coronary arteries that supply the heart tissue.
Then came time for them to be placed in the pressure cooker; they had to answer a series of rapid-fire questions involving mental arithmetic. "We kept badgering them to go faster," said Dr. Ray. To put the subjects off guard, they were repeatedly told they had given wrong answers when they were actually correct.
As expected, the math challenge provoked a typical stress response. All the volunteers experienced a spike in both heart rate and blood pressure.
"When the heart works harder, it requires more blood flow through the coronary arteries to supply the muscles of the heart," noted Dr. Ray.
Ultrasound scans revealed the responses weren't the same for men and women: Coronary blood flow increased in men during mental stress, but showed no change in women.
That means a woman's heart may not be getting enough oxygen-rich blood when she's experiencing emotional pressure.
The study participants were all young and healthy and felt no ill effects from the stress of the gruelling quiz. But the study indicates that older women may become more susceptible to heart problems when they are stressed.
Although younger women tend to have fewer heart attacks than men their own age, cardiovascular disease eventually takes its toll. "This [blood-flow issue]might be one of the means by which women have more cardiac events [heart attacks and strokes]over time," said Dr. Ray. He presented the study this week at the Experimental Biology conference in San Diego.
Dr. Ray and colleagues plan to do more research to determine why blood flow to the heart isn't the same for both sexes. That work could lead to new ways to protect women from heart disease.