In an article on InteliHealth.com (where the medical content of the article was reviewed by the faculty of the Harvard Medical School) pointed out that chronic or even frequent stress is bad for your heart.
Stress is a bad mood, and it isn't good for your heart (or any other part of your body). I quote the article:
"When an event is perceived as a threat — whether a deadline, a divorce, stalled traffic or misplaced keys — the body harks back to that ancient "fight-or-flight" response that once meant life or death. First, the stress hormones — adrenaline and cortisol (made by the adrenal glands) — flood the body, increasing the heart's need for oxygen as it prepares for vigorous action. Heart rate and blood pressure increase. Blood vessels in your skin constrict. Muscles tense and blood sugar levels increase. The tendency for blood to clot increases and the body's cells pour stored fat into the bloodstream. Add it all up and it puts additional strain on the heart and artery linings."
Did you catch that? "When the event is perceived as a threat." Of course, many times (maybe even most the time) you perceive something as more threatening than it really is. And regardless of how threatening it really is, your body responds to your perception, not the reality.
That's actually great news. That means if you would reframe some of the "stressful" things in your life, if you would see them in a new way, a less-stressful way, you would improve your health (and feel better too). Find out how: How to Reframe What Seems to Be a Negative Event.