4 of 14

Forget perfect

We all know that the type A personality—the one constantly striving for perfection—seems more prone to heart disease. But what it really boils down to, says Heffner, is hostility. "Hostility has been shown to be the key ingredient in what used to be termed the type A personality," she says. "Hostility is behavior that's fueled by anger toward other people." Research suggests that hostility may be a better predictor of heart disease than things like high blood pressure and being overweight.

So play nice and think nice thoughts about the future, as optimism has also been shown to protect the heart.

Next: Don’t hold grudges