Scientists explain stress and heart attack link

23rd June 2014 – Scientists say they may be able to explain how chronic stress increases the risk of having a heart attack.

They say stress triggers overproduction of disease-fighting white blood cells, which can increase inflammation in arteries in people with atherosclerosis, where the artery walls are thickened by a build-up of plaque.

Stress is a normal part of life, but if left unmanaged can contribute to health problems including coronary artery disease, high blood pressure, chest pains or irregular heartbeats.

Inconclusive

Medical research has so far been inconclusive about how stress increases the risk of heart disease. For instance, stress itself might be responsible, or it could be that high levels of stress contribute to other risk factors like high cholesterol or high blood pressure.

Studies have also linked stress to changes in the way blood clots, which increases the risk of heart attack.

Scientists from Massachusetts General Hospital and Harvard Medical School in the US looked at how exposure to chronic stress in 29 medical workers in a hospital’s intensive care unit affected their white blood counts after one week. This working environment was chosen because of its fast-paced nature where staff regularly have to make life-or-death decisions.

The authors of the study, published in Nature Medicine, report that when they compared blood samples taken from the volunteers during work to samples taken when off duty, the white blood cell count was higher from the work samples.

Mice studies

Next, the scientists exposed atherosclerosis-prone mice to stressful conditions by isolating them or tilting their cages until they produced excess white blood cells.

They found that this seemed to induce atherosclerotic plaque inflammation in the arteries of the mice. They say these plaques resembled the way in which excess white blood cells clump together on the inner wall of arteries in humans where they block circulation or are prone to break off and travel to other parts of the body, potentially triggering a heart attack.

Angina

The British Heart Foundation says there is no evidence to suggest that stress causes coronary heart disease or heart attacks.

However, it says that anxiety and stress may bring on symptoms like angina for people who already have coronary heart disease.

Additionally, it says the risk of a heart attack for people who are stressed may stem from how they deal with that stress – such as smoking, drinking too much alcohol and overeating.