Extreme Fatigue Increases Risk Of Blood Clot Formation

In the months before a heart attack, many people feel extremely tired. A new study suggests that people with this kind of exhaustion have elevated measures of blood clot formation.

The blood-clotting process plays an important role in heart attacks. This study indicates that an increased tendency to develop blood clots may be a link by which exhaustion relates to a future heart attack.

Fatigue, increased irritability, and feelings of demoralization are characteristic of "vital exhaustion," according to Willem Kop, a psychologist at the Uniformed Services University of the Health Sciences in Bethesda, Maryland, and his colleagues at the Cardiovascular Research Institute in Maastricht, the Netherlands.

The blood-clotting process involves two main components: factors that promote clot formation (coagulation) and factors that remove blood clots (fibrinolysis). "The relationship between vital exhaustion and risk of myocardial infarction may in part be mediated by an imbalance between blood coagulation and fibrinolysis," the scientists conclude in the May-June issue of Psychosomatic Medicine.

Blood was tested twice in a three-month period for fibrinolysis and coagulation factors in healthy volunteers. Initial psychological assessments were made in 334 men, and a group of 15 exhausted volunteers was selected. Exhausted subjects evidenced impaired fibrinolysis (higher levels of plasminogen activator inhibitor-1) compared to non-exhausted individuals.

This finding is consistent with previous research demonstrating increased blood clotting factors among chronically stressed individuals. The strength of the study lies in the careful psychological selection of the subjects. Although vital exhaustion is similar to depression in some ways, it does not include the feelings of intense sadness, guilt, and low self-esteem. These features of depression were not present in the exhausted group that was examined here.

Vital exhaustion may increase the risk of blood clot formation in the heart arteries through impaired fibrinolysis. Impaired fibrinolysis may provide a biological link explaining the association between feelings of exhaustion and future heart attacks, Kop and his co-workers propose. Assessing extreme fatigue may help to detect patients at risk for impending heart attacks, especially among individuals who already have a high-risk profile for heart disease.