In the largest brain-imaging study of cardiovascular stress physiology to date, researchers have introduced a brain-based explanation of why stress might impact a person’s heart health.
The findings, published in the Journal of the American Heart Association/American Stroke Association, show that as we experience stressful events, our brains produce a distinct pattern of activity that appears to be directly tied to bodily reactions — such as rises in blood pressure — that increase the risk for cardiovascular disease.
“Psychological stress can influence physical health and risk for heart disease, and there may be biological and brain-based explanations for this influence,” said Peter Gianaros, Ph.D., the study’s senior author and psychology professor at the University of Pittsburgh in Pennsylvania.
For the study, the researchers conducted mental stress tests and monitored the blood pressure and heart rates of 310 participants (157 men and 153 women) undergoing an MRI procedure. The mental tests were designed to create a stressful experience by having the participants receive negative feedback as they came up with time-pressured responses to computer challenges.
The participants (aged 30 to 51 years) were enrolled in the Pittsburgh Imaging Project, an ongoing study of how the brain influences cardiovascular disease risk. As expected, the mental stress tests increased blood pressure and heart rate in most of the volunteers compared to a non-stress baseline period.
Using machine-learning, the researchers discovered that a specific brain activity pattern could reliably predict the size of the participants’ blood pressure and heart rate reactions to the mental stress tests.
The brain regions that were especially predictive of stress-related cardiovascular reactions included those that determine whether information from the environment is threatening and that control the heart and blood vessels through the autonomic nervous system.
The research involved middle-aged healthy adults at low levels of risk for heart disease, so the findings may not be applicable to people with existing heart disease. In addition, brain imaging does not allow researchers to draw conclusions about causality.
“This kind of work is proof-of-concept, but it does suggest that, in the future, brain imaging might be a useful tool to identify people who are at risk for heart disease or who might be more or less suited for different kinds of interventions, specifically those that might be aimed at reducing levels of stress,” Gianaros said.
“It’s the people who show the largest stress-related cardiovascular responses who are at the greatest risk for poor cardiovascular health and understanding the brain mechanisms for this may help to reduce their risk.”