Increased activity in a deep-lying region of the brain called the amygdala is associated with a higher risk of heart attack and stroke, according to a study published in The Lancet.
The amygdala is known to process emotions such as fear and anger and the finding sheds light on the possible mechanism by which stress can lead to cardiovascular disease (CVD), say the study authors. It could also lead to new approaches to treating stress-related cardiovascular risk.
Previous studies have shown that stress is linked to an increased risk of CVD, but the mechanism behind this link has not yet been fully explained.
Lead author Ahmed Tawakol (Harvard Medical School) and colleagues performed two studies. The first involved 293 patients who had their brain, bone marrow, spleen and arteries scanned by PET/CT and were then tracked for 3.7 years to see whether they developed CVD. During this time, 22 participants experienced a CVD event including heart attack, angina, stroke, heart failure and peripheral artery disease.
The researchers found that patients who had higher activity in the amygdala were more likely to develop CVD and to do so sooner, than people with less amygdala activity.
The second study looked at the link between stress and inflammation among 13 people with a history of post traumatic stress disorder. Among those individuals, people who reported the highest stress levels had the highest levels of amygdala activity, as well as more evidence of inflammation in their blood and arteries.
The authors suggest a possible mechanism is the amygdala sending signals to the bone marrow, causing it to produce extra white blood cells. This could cause plaques and inflammation to develop in the arteries, which increases the risk of heart attack, angina and stroke.
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.”
Tawakol suggests that eventually stress could be treated as an important CVD risk factor and screened for and managed in the same way as other major risk factors.
Cardiac nurse Emily Reeve from the British Heart Foundation also thinks that finding out how the brain’s management of stress is linked to CVD risk could enable the development of new approaches to managing chronic psychological stress.
"This could lead to ensuring that patients who are at risk are routinely screened and that their stress is managed effectively," she says.