Optimistic people fare better when suffering from cancer, recover better from coronary bypass surgery, enjoy healthier immune systems, and live longer than pessimists. People with a positive outlook are 45% less likely to die from any cause than negative thinkers (and 77% less likely to die from heart disease). In a study of nuns, researchers found that 90% of the most cheerful nuns were still alive at age 84, compared to only 34% of the least cheerful.