New evidence may show the physiological link between stress and heart disease, as it manifests in the mind, and then, in the body. The study, reported in The Lancet (2017; doi: 10.1016/S0140-6736(16)31714-7), shows that heightened amygdala activity in the brain resulting from mental stress is related to more arterial inflammation and bone-marrow activity and is significantly associated with a greater risk of heart disease and stroke. Study authors noted that these findings “provide unique insights into mechanisms translating stress to cardiovascular disease events.”
Earlier animal studies have confirmed a link between stress, the amygdala, and more bone marrow and arterial activity. The amygdala, part of the ‘primitive’ limbic system in humans and other animals, is linked with memory and process emotional reactions like fear and pleasure and regulate ‘survival instincts’ [Margolies, L. (2016). Are Your Decisions from Your Evolved or Primitive Brain?. Psych Central. Retrieved on March 5, 2017, from https://psychcentral.com/lib/how- to-tell-if-your-decisions-are-from-your-evolved-or- primitive-brain-2/]. This investigation, conducted by Harvard University Medical School researchers at Massachusetts General Hospital in Boston, Massachusetts, is the first human study that shows the connection between heightened amygdalae activity to more bone marrow and arterial activity and a significantly higher heart attack and stroke risk. The amygdala may signal to the bone marrow to produce extra white blood cells which then cause arteries to develop plaque and become more inflamed, which, over time, contributes to heart attack and stroke.
Scientists identified this connection by giving 293 male and female patients with a median age of 55 years a PET/CT scan to record their brain, bone marrow and spleen activity and inflammation of their arteries. The patients were then tracked for an average of 3.7 years to see if they developed cardiovascular disease. During this follow-up, 22 patients had cardiovascular events including heart attack, angina, heart failure, stroke and peripheral arterial disease. Those with higher amygdala activity had a greater risk of subsequent cardiovascular disease and developed problems sooner than those with lower activity.
More research is recommended; however, these findings suggest that chronic stress could be treated as an independent risk factor for heart disease that can be screened for and managed, similar to other risk factors like high blood pressure or cholesterol levels. In other words, stress reduction not only makes you feel better, but also reduces your risks of heart disease.