Researchers from Harvard reported in Psychosomatic Medicine that it's healthy for men to get angry and express it once in a while. Notice the key words are "once in a while" which means this is not license to blow up at everything in your life. The researchers found a 50% lower risk of heart attack as well as a lower risk of stroke for men who got a little mad versus those who never let out their anger.
To me this figures, since anger that is suppressed all the time will wind up being stored somewhere in the body, and the heart and circulatory system make good candidates. There is another way of discharging your anger without having to express it and that can be by exercising, meditating or talking it out with a close friend.