Studies show that the healthiest way of dealing with anger appears to be expressing it calmly, rather than exploding or attempting to conceal it. People who are more likely to “blow up” over minor inconveniences, or who feel angry almost all the time, appear to be at greater risk of heart disease and/or heart attacks. Research has demonstrated a clear link between anger and cardiovascular health.

A groundbreaking study completed in 2004 found that anger and frustration can provoke abnormal heart rhythms (arrhythmia), which can lead to sudden cardiac death. Scientists discovered that mental stress caused arrhythmia more quickly than physical stress (e.g., exercising) in people with an implantable cardioverter defibrillator. This study was the first to show that mental stress alone can trigger arrhythmia, and researchers hope future studies will help identify personalities at higher risk for developing abnormal cardiac rhythms.

There have also been cases where anger has resulted in a severe coronary artery spasm that is capable of causing changes similar to a heart attack or leading to severe permanent heart damage. In some cases these damages may be reversible with time.

Anger plays a strong role in the development of heart disease. One study found that men who bottled up their anger had a 75 percent higher chance of developing coronary artery disease than men who vented or talked through their anger. Anger was also linked to high blood pressure and high levels of calcification, two risk factors for heart disease.

Men with the most intense levels of anger have three times greater risk of a heart attack and/or a type of chest pain called angina than men with the least intense anger levels, according to some studies. The risk seems to be especially high for men who become angry enough to want to break things or to physically strike out at someone.

Other studies suggest that even lower levels of negative behavior can impact heart health. For instance, a study found a significantly higher risk of heart disease for people with impatient, irritable and/or dominant personalities (shown by interrupting other people, for example) as compared to more patient personalities.

The damaging effects of anger may accumulate over time. A 2002 study found that heart attacks appear to increase in those who respond to stress with high levels of anger, either expressed or concealed. The study was notable because it focused on young men and followed them for 48 years.