For the first time, researchers have identified a biological connection between stress and heart disease.
Researchers at Harvard University in Massachusetts have discovered a brain structure, called the amygdala, is more active in people who suffer from chronic stress.
That in turn, the evidence shows, promotes an immune response that can lead to heart disease.
Dr. Ahmed Tawakol is a cardiologist and researcher at Massachusetts General Hospital and Harvard Medical School, and lead author of the study.
Tawakol said the amygdala is the region of the brain that is most responsive to external threats, and has shown to be more active in those with stress disorders, even at rest.
The study involved the brain imaging of almost 300 individuals who researchers then followed for up to five years to see how many suffered a cardiac event.
During the follow-up period, Tawakol said 22 of the study participants suffered a heart attack or stroke.
“And what we found is that the degree to which the amygdala was metabolically active, the degree to which it lit up on imaging – and we can quantify that – nicely predicted the risk of subsequent cardiovascular disease events,” said Tawakol.
Not only that, researchers saw the highest amygdala activity in those who experienced the cardiovascular events sooner than those with lower amygdala activity.
“Those with high activity had very near term events. Those with intermediate activity had later events, and those who had never had an event had the lowest activity of all. So there was a nice connection from several levels linking the amygdala metabolic activity with these subsequent events,” said Tawakol
The findings were published in the journal The Lancet.
Researchers also found that people with the highest amygdala activity, in other words those who were the most stressed out, had the highest levels of inflammatory markers in their blood.
Inflammation in the walls of arteries can lead to heart disease.
Doctors have long known, and largely accepted as fact, that people who are more stressed tend to have more heart attacks and strokes. In fact, observational studies have shown that stress could be as potent a risk factor for heart disease as high blood pressure and smoking.
Until now, the reason for a link between stress and heart disease has been unclear. But the findings of the first-of-its-kind study identify a biological connection between the two.
Tawakol says it’s possible that reducing stress levels, through drugs or conditioning, might lower the risk of heart disease, something he’s interested in finding out.