Staying stress free in your twenties reduces high blood pressure risk later on

Avoiding stress in your 20's could reduce the risk of developing high blood pressure in middle age, according to a report in today's issue of Circulation: Journal of the American Heart Association.

Twenty somethings who react to psychological stress with spikes in blood pressure are more likely to have high blood pressure when they are in their 40s. Assessing blood pressure changes in response to stress may be a useful additional tool for determining a person's future risk of high blood pressure, said lead researcher Karen A. Matthews, Ph.D., a professor of psychiatry at the University of Pittsburgh.

High blood pressure makes the heart work harder than normal which in turn increases the risk of heart attacks, strokes and kidney failure.

"In general, the individuals who had larger blood pressure responses to stress, had a greater risk for developing high blood pressure," Matthews said. "This risk was independent of other known risk factors such as race, gender, education, age, and body-mass index (BMI)."

The findings are based on data collected in the CARDIA study, which is an ongoing prospective study tracking the natural history of cardiovascular disease. From 1985 to 1986, the study enrolled 5,115 men and women, ages 18 to 30. Patients were reexamined at 2, 5, 7, 10 and 15-year intervals.

At the 2-year examination, 4,202 participants completed stress testing. These participants had normal blood pressure at this examination, meaning a systolic pressure of less than 140 mmHg and diastolic pressure of less than 90 mmHg. Participants were considered to have high blood pressure if their pressure was 140/90 mmHg or higher at a follow-up visit or if they were taking medications to control blood pressure.

Participants took three different stress tests and researchers measured the change in their blood pressure. In the cold pressor test, participants plunged a hand in ice cold water and kept it submerged for 45 seconds. Another test, star tracing, required that participants trace a star with a stylus through a mirror image of the star.

And finally, the participants played a video game, but Matthews noted that since the tests were done in the late 1980s, video games were more novel than now.

"In general, participants who had the greatest blood pressure increases during all three tasks had the highest risk for later high blood pressure," said co-author Mary A. Whooley, M.D., assistant professor in the departments of Medicine and Epidemiology and Biostatistics at University of California, San Francisco.

The greater the blood pressure changes in all three tasks, the earlier the onset of hypertension.

"Take, for instance, two women similar with characteristics such as age, education, and BMI," she said. "One of the women is in the top quarter of change in blood pressure due to stress while the other is in the lowest quarter. The woman who was very reactive was also among those who developed hypertension the soonest."

Each unit increase in blood pressure change was associated with a 9 percent to 12 percent decrease in time to systolic hypertension and a 12 percent to 18 percent decrease in time to diastolic hypertension.

Some tasks were more sensitive as predictors for subgroups, researchers said. Changes in diastolic blood pressure during the video game were a better predictor for men. Changes in systolic pressure during the cold pressor test were more predictive for women and whites. The study didn't assess ways to reduce blood pressure spikes caused by stress, but Matthews said that one plausible--although unproven--way to reduce the stress risk is by exercise. "People who are active and physically fit may have smaller stress responses or their blood pressure may return to normal more quickly," she said.

After 13 years of follow-up, 353 participants developed high blood pressure.

"This study confirms previous work demonstrating an association between blood pressure response to various stressors and the future development of hypertension," said American Heart Association spokesperson Daniel W. Jones, M.D. "It is still unclear whether exposure to stress is a part of the cause of hypertension in some people or whether these tests measuring response to stress are simply good markers for the future development of hypertension. Further research in this area is needed to understand the role of stress in the development of hypertension and possible management tools for reducing that risk."