Fresh off news that optimism helps heart patients live longer, a review of 160 studies has concluded happiness is linked to longevity.
The review, conducted by researchers at the University of Illinois, is the most comprehensive set of evidence linking happiness to health. The study's lead author, Ed Diener, professor emeritus of psychology and a scientists for the Gallup organization, analyzed human and animal trials and studies linking health to natural events.
According to Diener, "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."
Diener says he "was almost shocked" by the consistency of the data across studies and that while happiness may not actually cure diseases, evidence suggests positive feelings are more closely linked to positive health outcomes than obesity is to negative outcomes.
"Happiness is no magic bullet," he said. "But the evidence is clear and compelling that it changes your odds of getting disease or dying young."
The experiments Diener and his team looked at were wide ranging. One following 5,000 university students found those who were more cynical during school died younger than their peers, while another following 180 Catholic nuns throughout their lives found those who wrote positive journals usually outlived those who wrote more negative autobiographies. Other studies linked marriages rife with conflict to reduced immune function and slower wound healing.
Animal studies linked stress to heart disease, weakened immune systems and early deaths. Lab experiments on humans found good moods boosted immune systems, lowered stress-related hormones and improved heart recovery times.
Diener suggests his findings point to a new public health strategy. "Current health recommendations focus on four things: avoid obesity, eat right, don't smoke, and exercise. It may be time to add 'be happy and avoid chronic anger and depression' to the list."