By AMERICAN HEART ASSOCIATION NEWS
How well does your body react to a fight with a loved one? A face-off with the boss? A major loss by your favorite sports team?
It could depend on what kind of brain you have.
Stressful events trigger a temporary increase in blood pressure for many people, but now a new study examines just what role the human brain plays in shaping cardiovascular changes during those times of tension.
While these short-term changes may help the body respond to stress at the time of the event, they may increase a person’s risk for high blood pressure and even premature death from cardiovascular disease over the long run.
A new study published Wednesday by the Journal of the American Heart Association describes how researchers found a pattern of brain activity that predicted blood pressure spikes from stress among some people.
This brain pattern may help reveal the influence psychological stress can have on physical health – and how some risk factors for heart disease and stroke may depend on what’s inside a person’s head, perhaps as much as how well an individual treats the body.
“We’re sort of looking under the hood, so to speak, to try to understand what brain activity for a given person can tell us about why that person’s cardiovascular system is responding to stress in a certain way,” said neuroscientist Peter Gianaros, Ph.D., the study’s lead researcher. “The idea is to basically say, okay, can you look at someone’s pattern of brain activity during stress and then predict how much the blood pressure is going to go up?”
The study focused specifically on blood pressure because previous research has indicated that the more blood pressure increases during stress, the more likely the risk for cardiovascular disease in the future.
In the study, researchers used functional MRI to capture images of brain activity in 310 adults as they performed stressful mental activities. The images revealed a pattern of brain activity that researchers used to predict which stressed-out subjects would get a bump in their blood pressure.
Researchers said the findings reflect the largest brain imaging study to date of cardiovascular stress physiology.
“What we found is that you have to step back and see the whole brain. It’s not like there’s only one part of the brain that you can say, ‘Ah ha! This is the spot that predicts cardiovascular stress reactions,’” said Gianaros, a psychology and psychiatry professor at the University of Pittsburgh.
But some parts of the brain – including portions of the frontal lobe and the amygdala, which governs fear, stress and emotion – contributed more than others within the pattern. Those areas were consistent with similar past research that has been conducted on animals, Gianaros said.
The brain pattern, however, was only able to predict about 9 percent of the differences between people in terms of how their blood pressure increased with stress. “This means that there is a lot left to be learned about what accounts for the effects of stress on blood pressure in the moment,” Gianaros said.
“It’s statistically significant, but how this might be helpful from a patient’s standpoint is far from clear,” said Larry B. Goldstein, M.D., professor and chairman of the University of Kentucky’s neurology department.
Still, the study provides additional insight into the brain’s response to stress and its relationship to risk factors for stroke, heart attacks and other vascular illnesses, he said.
“It is another step in trying to understand what may be an underlying mechanism of this exaggerated blood pressure response.”
Goldstein, who also co-directs the Kentucky Neuroscience Institute, said the study’s findings don’t entirely establish causality. He said people who experience short-term blood pressure increases from stress “may have had this exaggerated response their entire lives, and we know that changes in the body can cause functional alterations in the brain, so it’s a ‘which came first – the chicken or the egg?’”
As an example, he noted that the amputation of a person’s arm or leg will change the way that individual’s brain responds to where the limb used to be.
“It’s the brain responding to peripheral stimuli as opposed to the brain causing a peripheral, secondary response,” he said.
Goldstein noted scientists are “just beginning” to probe the link between brain activity and heart disease and stroke.
Gianaros agreed. He said his study “opens the door” for additional brain imaging research that can help understand the mind’s link to cardiovascular disease risk. It also complements another study released earlier this year that found people with heightened activity in the amygdala may be at higher risk for heart disease and stroke.
“That work and our work point to the possible future integration of brain imaging methods into cardiovascular disease research,” Gianaros said.
“You can envision a future, if this work plays out, where when you go and get your blood work done, and you can image your vessels. Then, you might have brain scans that could add to determining your risk profile, which may help you manage your health.”