Stress has long been known to influence heart health. Now, researchers found that the amygdala, the fear center in the brain, can help explain how stress can cause heart attack, stroke, and other cardiovascular events.

Amygdala: The Fear Center Of The Brain

The amygdala is an almond-shape set of neurons associated with fear and other forms of stress. Research has shown that it has important role in the processing of emotional reactions, decision-making, and memory.

More Active Amygdala And Heart Attack Risk

In the new study published in The Lancet medical journal on Jan. 11, researchers found that people whose amygdala was more active during brain scans tend to have increased risk of suffering from heart attack, stroke, and other serious heart events over the next few years.

The researchers likewise found that individuals with more active amygdala had more inflammation in their arteries, which is associated with heart disease, and increased bone marrow activity that may be associated with blood clots.

For the new study, Ahmed Tawakol of Massachusetts General Hospital and colleagues watched nearly 300 patients who were getting PET and CT scans, all of whom had their bone marrows, arteries, brains, and spleens scanned. Twenty-two of the participants had heart attack, strokes, or suffered from other heart diseases over the next three to four years.

The researchers found that those whose amygdalas appeared more active in brain scans were more likely to suffer from a heart event and the link remains significant even after the researchers took into account other cardiovascular risk factors such as diabetes, smoking, and hypertension.

"We were surprised at how robustly amygdalar activity predicted hard cardiovascular events, along with providing information on the timing of those events," Tawakol said.

In a second study involving 13 individuals, the researchers looked at the relationship between the levels of stress and inflammation in the body and found that participants who reported the highest levels of stress also had the highest level of activity in the amygdala. They also had more inflammation in the blood and arteries.

The findings of the study suggest a complex chain of event that can help explain the link between stress and heart attack risk.

Stress can activate the amygdala, which can lead to the production of extra immune cells by the bone marrow. This, in turn, may impact the arteries and cause inflammation, which can lead to cardiovascular events such as stroke and heart attack.

Chronic Stress As Important Risk Factor For Cardiovascular Disease

The researchers said that chronic stress may eventually be treated as another crucial risk factor for heart disease.

Experts said that job insecurity, heavy workloads, and living in poverty are just some of the instances that can lead to chronic stress, which can also result in chronic psychological disorders such as depression.

"Amygdalar activity is involved partly via a path that includes increased bone-marrow activity and arterial inflammation," the researchers wrote in their study. "These findings provide novel insights into the mechanism through which emotional stressors can lead to cardiovascular disease in human beings."