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Researchers Find Link Between Stress and Heart Disease (dateline July 12, 2002)


While experts have suspected for years that stress increases the risk for heart disease, a new study offers the first concrete link between mental anguish and impaired functioning of the blood vessels. In the study, the blood vessels of patients who experienced stress were less able to respond to changes in blood flow—a condition which the researchers say increases the patients’ risk of heart attack or stroke. The study also found that blocking a certain chemical (called endothelin-A) returned the blood vessels to normal functioning. They believe this technique may be a new approach to help prevent blood vessel impairment.

Heart disease is the number one cause of death in the United States and Europe. Approximately 12.8 million Americans suffer from coronary artery disease and nearly 500,000 Americans die from heart attacks caused by heart disease. Over 12 million Americans have a history of heart attack, angina (chest pain), or both.

Coronary artery disease usually results from atherosclerosis, a condition that occurs when arteries become narrow and hardened due to cholesterol plaque build-up. Atherosclerosis can occur from a variety of factors, including high blood pressure (hypertension) or high cholesterol. Further, researchers know that atherosclerosis is often a result of endothelial dysfunction, an impairment of the blood vessels. To determine whether stress can also causes blood vessel impairment, Georg Noll, MD, of University Hospital in Zurich, Switzerland, and his colleagues performed 3-minute stress tests on healthy patients between the ages of 20 and 31 and then examined the functioning of their blood vessels.

The researchers used ultrasound to study the patients’ blood vessels both before the stress exercises and 10 minutes afterwards. Six of the patients in the study received an infusion of an Eta receptor blocker, a drug known to block the chemical endothelin-A, which is thought to further impair blood vessel functioning. Five of the patients received saline instead of the drug. The mental stress activity consisted of responding as fast as possible to colored lights by pushing a button of the corresponding color.

After the test, Dr. Noll and his colleagues found that patients’ blood vessels were significantly impaired by the mental stress activity. Their blood-vessel dilation decreased and their blood pressure and heart rates increased. According to the researchers, by showing that mental anguish causes blood vessel impairment (endothelial dysfunction), the study has identified an important new link between stress and atherosclerosis (hardening of the arteries), which is a precursor to heart disease.

While stress induced blood vessel impairment in the study, the infusion of the ETa receptor blocker drug completely prevented the impairment. Thus, Dr. Noll and his colleagues believe they have identified the chemical endothelin-A as a cause of artherosclerosis—a cause that can be prevented with the Eta receptor blocker.

Though the study is small, the researchers say it is an important first step in better understanding the link between stress and heart disease. According to Dr. Noll, researchers are trying to understand how sudden life events, such as anger or bereavement, can cause sudden cardiac death.

Other, better understood risk factors for heart disease include:

  • Age
  • Family history
  • High cholesterol or blood pressure
  • Smoking
  • Diabetes (Type II)
  • Obesity
  • Lack of physical activity

Many of these factors, including high blood pressure and high cholesterol are associated with stress, as are an increased tendency to smoke, gain weight, and/or decrease physical activity.

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