Happiness: the secret to a longer life?

Want to live a long life? Then get happy.

Happy people reduce their risk of premature death by an impressive 35 per cent, a new study out of London's University College found.

Published in the online edition of the Proceedings of the National Academy of Sciences, the study used Ecological Momentary Assessment, a technique that measures a person's current happiness level in real time, to rate happiness and anxiety levels of nearly 4,000 participants aged 52 to 79 over the course of a day, and then divided them into three groups according to happiness level and tracked them for the next five years, recording the number of deaths in that period.

Higher rates of happiness seemed to dictate longer lives, even when the researchers controlled for chronic health problems, finances, gender and other factors. At the end of the study, 7.3 per cent of people in the least happy group died, while only 3.6 per cent in the happiest group died.

"We had expected that we might see a link between how happy people felt over the day and their future mortality, but we were struck by how strong the effect was," said Andrew Steptoe, Ph.D., the lead author of the study.

"(Happiness) affects nearly every aspect of our physical health," Dr. Holly Phillips, an internist, shared on "The Early Show." "The first would be, of course, we have a healthier heart. A previous study showed people who were happy had a 22 percent lower risk of suffering from heart disease — our top killer — than people who are unhappy. It also combats stress. Stress is linked with cancer, among many other illnesses. And (happiness) boosts our immune system. People who are happy have more white blood cells and actually more natural killer cells, which help us to fight off viruses."

Does the study prove that happiness equals longevity? No, not directly. But researchers say the findings "do imply that doctors and caregivers should pay close attention to the emotional well-being of older patients," CNN reports.

"I hope they continue to follow this group out to 10 years and 15 years," says Stephen Post, professor of preventive medicine at Stony Brook University. Post believes that over time, the mortality gap between the happy and not-so-happy will increase.