Folks who feel "young at heart" may be more likely to live to a ripe old age, a new British study suggests.
Seniors who said they felt three or more years younger than their actual age experienced a lower death rate over the course of eight years than people who either felt their full age or a little older, researchers report online Dec. 15 in the journal JAMA Internal Medicine.
About 25 percent of people who felt older than their actual age died, compared with about 14 percent of people who felt younger than their true age and almost 19 percent who felt their age.
The effect held even after researchers accounted for things that might make a person feel older than they are, such as chronic health problems, difficulty with mobility or mental health issues like depression, said senior study author Andrew Steptoe, director of the Institute of Epidemiology and Health Care at University College London.
People who felt older still had a 41 percent greater risk of death than those who felt younger, even after researchers controlled for those factors. However, the study did not prove definitively that feeling younger lengthened a persons life span.
"None of these fully explained the relationship we saw, so we don't understand all the mechanisms involved," Steptoe said.
The researchers based their findings on data gathered during a long-term study on aging in Britain. As part of the study, all participants were asked, "How old do you feel you are?"
More than two-thirds of participants felt three or more years younger than their actual age, while about a quarter felt their age. About 5 percent felt more than a year older than their true age.
The average actual age of all participants was about 66, but their average self-perceived age was 57.
The findings show how powerful optimism can be when it comes to a person's overall health, said James Maddux, professor emeritus of psychology and senior scholar at the Center for the Advancement of Well-Being at George Mason University, in Fairfax, Va.
"Optimism in many ways is a self-fulfilling prophecy," he said. "If you feel your life and your health is largely under your control, and you believe you are capable of doing things like managing stress, eating right and exercising, then you are more likely to do those things."
Maddux noted that self-perceived age had a strong effect on a person's risk of death from heart disease, but made no difference in a person's risk of death from cancer.
More than twice as many people who felt older than their true age died from heart-related illness, compared with those who felt young -- 10.2 percent, compared with 4.5 percent.
"We do know that anxiety and poor management of stress can put people at increased risk of cardiovascular disease, while the link between those emotions and cancer is much weaker," Maddux said. "It's not a surprise to me that they found this link for cardiovascular disease but not for cancer."
Steptoe said the results are so striking that doctors might want to consider asking seniors how old they feel as a part of their annual physical exams.
"Perhaps the beliefs and feelings that people have tell us something that our other measures of health and well-being do not capture," he said. "Asking someone how old they feel is a very easy thing to do, so if it tells us something important about health, we need to understand it better."
In addition, people who are naturally pessimistic might consider turning over a new leaf, Maddux said.
"Optimism pays off. Even though there probably is a large genetic component to whether you are optimistic or pessimistic, we also know from research that optimism can be learned," he said. "It's a trait that's worth picking up."