The part of the brain linking stress to the risk of heart attack and stroke has been identified for the first time, researchers say.
The findings could indicate that reducing stress has an important physical as well as psychological benefit, scientists said.
Almost 300 patients were tracked for an average of 3.7 years - 22 of whom suffered heart-related illnesses during that period including angina and stroke.
Those with higher activity in the amygdala region of the brain, the part associated with stress, had a greater risk of cardiovascular disease and developed problems sooner than those with lower activity.
The US authors suggested the amygdala sends signals to the bone marrow to produce extra white blood cells, which act on the arteries, causing them to develop plaques and become inflamed, which can cause heart attack and stroke.
"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," said lead author Ahmed Tawakol, of Massachusetts General Hospital and Harvard Medical School.
"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."
Commenting on the study, published in the Lancet, Ilze Bot of Leiden University in the Netherlands, said more research is needed to confirm the mechanism identified by scientists, but added that it could be useful given increasing levels of stress in society.
"In the past decade, more and more individuals experience psychosocial stress on a daily basis," Dr Bot said.
"Heavy workloads, job insecurity, or living in poverty are circumstances that can result in chronically increased stress, which in turn can lead to chronic psychological disorders such as depression.
"These clinical data establish a connection between stress and cardiovascular disease, thus identifying chronic stress as a true risk factor for acute cardiovascular syndromes, which could, given the increasing number of individuals with chronic stress, be included in risk assessments of cardiovascular disease in daily clinical practice."
