Heres another study that says hostility can hurt your heart.
Doctors from Coral Gables, Fla., compared the efficiency of the hearts pumping action in 18 men with coronary artery disease to nine healthy controls.
Each of the study participants underwent one physical stress test (riding an exercise bicycle) and three mental stress tests (doing math problems in their heads, recalling a recent incident that had made them very angry, and giving a short speech to defend themselves against a hypothetical charge of shoplifting). Using sophisticated X-ray techniques, the doctors took pictures of the subjects hearts in action during these tests.
For all the subjects, anger reduced the amount of blood that the heart pumped to body tissues more than the other tests, but this was especially true for those who had heart disease.
Why anger is so much more potent than fear or mental stress is anybodys guess. But until we see more research on this subject, it couldnt hurt to count to 10 before you blow your stack.