Ed Diener, professor emeritus of the University of Illinois at Urbana-Champaign, and colleagues reviewed more than 160 studies involving humans and animals under stress.
"We reviewed eight different types of studies," Diener said in a statement. "And the general conclusion from each type of study is that your subjective well-being -- that is, feeling positive about your life, not stressed out, not depressed -- contributes to both longevity and better health among healthy populations."
The study, published in the journal Applied Psychology: Health and Well-Being, found positive moods reduce stress-related hormones, increase immune function and promote the speedy recovery of the heart after exertion while anxiety, depression, a lack of enjoyment of daily activities and pessimism all are linked to higher rates of disease and a shorter lifespan.
"I was almost shocked and certainly surprised to see the consistency of the data. All of these different kinds of studies point to the same conclusion: that health and then longevity in turn are influenced by our mood states," Diener says.
"Happiness is no magic bullet, but the evidence is clear and compelling that it changes your odds of getting disease or dying young."