The following article comes from the U.S. News ebook, How to Live to 100, which is now available for purchase.
There's truth to the adage that you're only as old as you feel. "Physical well-being and subjective well-being are two sides of the same coin," says Howard Friedman, author of The Longevity Project, a research-based look at who lives the longest and why. "Mental health affects physical health, and physical health affects mental health."
Research paints a compelling argument. Adults with serious mental illness like schizophrenia die about 25 years earlier than the general population, according to a 2007 report from the National Association of State Mental Health Program Directors. They're 3.4 times more likely to die of heart disease or diabetes, 3.8 times more likely to die in an accident, 5 times more likely to die of respiratory ailments, and 6.6 times more likely to die of pneumonia or flu, found the team led by Joseph Parks, director of the Missouri Institute of Mental Health.
Why? They often get little exercise, leading to obesity and hiking the odds of diabetes and heart disease. They're also more likely than others to smoke and have alcohol and drug-abuse problems. It's common for their medical needs to slip through the cracks, too, because they often cannot adequately advocate for their own health.
But evidence of the mind-body connection transcends serious mental illness and the unhealthy habits that often go along with it. Take negative emotions, for example. While they may not cause a disease, they appear to accelerate its progression, says Laura Carstensen, a professor of psychology at Stanford University and author of A Long Bright Future. Research suggests that HIV infections progress faster in gay men who are closeted than those who live openly. That's likely because the brain translates that fear of rejection and isolation into physical stress, which can weaken the immune system. "We're only beginning to understand the potential mechanisms that could be involved," she says. "But it's clear that people who are more positive are more likely to survive, and to survive longer."
In one study, older people were up to 35 percent less likely to die during a five-year period if they reported feeling happy, excited, and content on a typical day. That was true regardless of factors like chronic health problems, depression, and financial security, according to findings published in 2011 in the Proceedings of the National Academy of Sciences. And earlier this month, after analyzing more than 200 studies on cardiovascular risks and emotional state, Harvard researchers reported that optimism, hope, life satisfaction, and happiness are associated with lowered likelihood of heart disease and stroke.
Social psychologists report similar results, including hints that attitudes about aging count, too. A research team at Yale University and the National Institute on Aging looked at surveys taken by 386 men and women under age 50, and then studied their health records four decades later. Those with the worst outlook on aging, who described older people as "feeble, helpless, and absent-minded," were significantly more likely to have had a heart attack or stroke than those with more positive views on growing old. Likewise, research suggests that people who perceive themselves as being in poor health—even if they aren't—may die sooner than those who consider themselves healthy.
Perhaps it's a self-fulfilling prophecy. If you view older people as active, healthy members of society, there's a good chance you'll take care of yourself as you age, continuing to eat well and exercise. But if you feel doomed to an enfeebled existence, you might be more inclined to let yourself go. Longevity scientists have found that people who perceive aging as a positive experience are more likely visit the doctor regularly, eat a balanced diet, maintain an appropriate weight, use a seat belt, and avoid tobacco.