SAN ANTONIO People whose blood pressure shoots up during stressful mental challenges are more likely to get hardening of the arteries, which can lead to heart attacks and strokes, a study found.
While stress is often portrayed as uniformly bad, the new work suggests its effects vary dramatically from person to person. Some handle frustrations with little change in blood pressure, yet it soars in other people.
Experts have long known that people with consistently high blood pressure risk getting atherosclerosis, the cholesterol-clogging of blood vessels commonly called hardening of the arteries. Just how stress plays into this is unclear.
However, animal experiments have shown stress is a potent contributor to blocked arteries in monkeys. So researchers from the University of Western Ontario set out to see if the same is true in people.
They used a diabolical computer game, called the color-word interference task, to check 348 diverse volunteers' reaction to stress. They were required to quickly identify the color in which the words for colors were written. For instance the word "red" might be spelled out in yellow. So "yellow" is the correct answer.
To make matters worse, the game was programmed to speed up until everyone made errors 17 percent of the time, no matter how hard they tried. All the while, they were hooked up to blood pressure monitors.
"When I did this, I got very angry. I only did it once and hated it," said Dr. J. David Spence, who presented the research Saturday at the American Heart Association's annual stroke conference.
Overall, the volunteers' blood pressures did not go up much during the 20-minute game. The average increase was 10 points of systolic pressure the first of the two blood pressure numbers and six points of diastolic pressure.
Some people's blood pressures actually fell during the exercise. But for others, blood pressure soared. Some went from a normal 120 over 80 to a seriously elevated 174 over 124.
The researchers then used ultrasound over the next two years to measure the amount of obstruction in the volunteers' carotid arteries, the blood vessels in the neck that feed the brain.
They found that those who had reacted most powerfully to mental stress developed the most new deposits in their carotid arteries. Even when they looked at all the other known contributors to this disease, such as smoking and diabetes, the reaction to stress was the most potent contributor to atherosclerosis.
"There is a big variation, and those who really react to stress are the ones who really get into trouble," said Spence.
He said he believes the test is a good stand-in for the way people respond to the hassles of ordinary life.
"If your blood pressure goes up during this, it probably also goes up when you are mad at your boss, mad at your wife, cut off in traffic or experience any one of a number of everyday stressful events," Spence said.
Spence said it may be possible to help people control this reaction with stress reduction techniques. Medicine may also help. In monkeys, it appears that widely used blood pressure pills called beta blockers can help soften the effects of stress-induced blood pressure surges on the arteries. Whether the same is true for people is still not known.
"It's provocative," Dr. Philip A. Wolf of Boston University said of the research. "The blood pressure goes way up, and that's the key."
However, Dr. Wesley S. Moore of the University of California, Los Angeles, was skeptical. It may be widely fluctuating blood pressure that's harmful, he said, and "it's a little leap of faith" to conclude that stress is an especially important trigger.