BOSTON (CBS Connecticut) – According to a new study, chronic stress may lead to heart attacks and strokes.
A surplus of white blood cells can be harmful in excess. A clump of cells together on the inner walls of the arteries can restrict blood flow and encourage the formation of clots that block circulation to parts of the body.
“White blood cells are important to fight infection and healing, but if you have too many of them, or they are in the wrong place, they can be harmful,” Matthias Nahrendorf of the Harvard Medical School, and co-author of the study told AFP.
Earlier studies showed chronic stress lead to heart disease but doctors could not link why. Nahrendorf and his team studied 29 medical residents to find it.
The team worked in an intensive care unit, which is considered a model for chronic stress exposure due to its fast pace and heavy responsibility.
The participants gave blood samples during work hours and while off duty. They were also asked to answer a stress perception questionnaire. The researchers found a link between stress and the immune system.
The researchers noticed stress activate bone marrow stem cells. These cells can trigger overproduction of white blood cells.
Researchers also studied mice. They exposed mice to stress by overcrowding them and tilting their cage.
The researchers found that excess white blood cells produced as a result of stress on the inside of arteries led to plaque growth.
“Here, they release enzymes that soften the connective tissue and lead to disruption of the plaque,” Nahrendorf said. “This is the typical cause of myocardial infarction and stroke.”
Other factors such as high cholesterol, smoking, high blood pressure, and genes can contribute to risks of having a heart attack or stroke.
“Stress might push these over the brink,” Nahrendorf added.