Previous research has suggested there’s a link between an acute episode of anger and an increased risk of heart attack. Researchers from Columbia University Irving Medical Center, Yale School of Medicine, St. John’s University in New York and other institutions wanted to tease out why.

To answer that question, they’d need to make some people angry.

The investigators recruited 280 healthy young adults and randomized them into four groups: a control group that counted out loud for eight minutes and maintained a neutral emotional state, and groups who recalled events that made them angry, sad or anxious. Before they began, and at intervals for 100 minutes afterward, the researchers took blood samples and measurements of blood flow and pressure.

The findings, published Wednesday in the Journal of the American Heart Association, show that anger may indeed affect the heart because of how it impairs blood vessel function.

The researchers found blood vessels’ ability to dilate was significantly reduced among people in the angry group compared with those in the control group. Blood vessel dilation wasn’t affected in the sadness and anxiety groups.

Dilation can be regulated by endothelial cells, which line the insides of blood vessels. By dilating and contracting, blood vessels slow down or increase the flow of blood to the parts of the body that need it.

Further tests revealed that there was no damage to the endothelial cells or to the body’s ability to repair any endothelial cell damage.

The only issue was the dilation, the study found. Impairment of how blood vessels dilate is an early marker for atherosclerosis, which is the buildup of fats and cholesterol, called plaque, on artery walls that make the arteries stiff. Atherosclerosis can lead to coronary heart disease, heart attack, stroke and kidney disorders.

“That is why endothelium-dependent vasodilation is an important mechanism to study,” said co-author Andrea Duran, an assistant professor of medical sciences at Columbia University Irving Medical Center, using the medical terminology for the impairment seen in the study.

The results of the study could help physicians persuade their patients who have heart disease and anger problems to manage their anger, through yoga, exercise, cognitive behavioral therapy or other established techniques, said Dr. Holly Middlekauff, a cardiologist and a professor of medicine and physiology at UCLA’s David Geffen School of Medicine.