Stress Linked to Heart Disease, Stroke

Stress may increase brain activity and lead to inflammation of the heart.

Smoking, high blood pressure, diabetes, and a lack of a healthy lifestyle all increase the risk of developing heart disease. Findings from a new study, however, suggest that increased activity in the amygdala associated with stress is also linked to a higher risk of heart disease and stroke.

These results may lead to novel targeted treatments for cardiovascular disease caused by stress, according to a study published by The Lancet.

Prior animal studies have found that stress leads to increased activity in bone marrow and the arteries, but these findings have yet to be proven in humans. Other studies suggest that the amygdala is increasingly active in patients with PTSD, anxiety, and depression.

In the current study, 293 patients underwent a PET/CT combination scan to image their brain, bone marrow, spleen activity, and arterial inflammation. Patients were followed-up with for an average of 3.7 years to determine if they went on to develop cardiovascular disease, or experience a cardiovascular-related event, according to the study.

The researchers found that during the follow-up time, 22 patients experienced heart attack, angina, heart failure, stroke, and peripheral arterial disease. Patients who had higher amygdala activity were more likely to develop cardiovascular disease, and experience related events compared with patients who had lower activity, according to the study.

Additionally, higher amygdala activity was associated with higher bone marrow activity and arterial inflammation. These findings suggest that these factors may influence cardiovascular risk, the authors noted.

The investigators hypothesized that there may be a biological mechanism in which the amygdala signals the bone marrow to create extra white blood cells, which then causes arteries to develop plaque and become inflamed. These events would result in heart attack and stroke, according to the study.

A small study that included 13 patients with PTSD was conducted. These patients had their stress levels assessed by a psychologist, underwent a PET scan, and had their C-reactive protein levels measured, according to the study. These proteins are known to be linked to inflammation.

The researchers found that patients who had the highest stress levels were also more likely to have high levels of amygdala activity, and signs of inflammation in their blood and arteries.

"Our results provide a unique insight into how stress may lead to cardiovascular disease. This raises the possibility that reducing stress could produce benefits that extend beyond an improved sense of psychological wellbeing," said lead author Ahmed Tawakol, MD. "Eventually, chronic stress could be treated as an important risk factor for cardiovascular disease, which is routinely screened for and effectively managed like other major cardiovascular disease risk factors."