We've been bombarded over the years with warnings about all the things we shouldn't do to protect our health and help us live longer, such as smoking, eating the wrong foods, drinking too much alcohol, and so forth.
Now, someone has taken a look at the opposite side of that coin to see whether the positive things we can do can be as important as the negative things we shouldn't do.
And here's what they found: Believing you are in control of your own life, maintaining strong social ties to friends and family, and getting off the couch for vigorous exercise can delay the effects of aging by at least a decade.
So what it all means is what you do today (not just what you shouldn't do) will determine what you are tomorrow. And the research suggests this is probably a lifelong process, so it's never too soon to get started.
Psychologists Margie E. Lachman and Stefan Agrigoroaei of Brandeis University in Boston delved into the Midlife Development in the United States study (MIDUS), a national interagency resource involving 3,626 adults aged 32 to 84 who were interviewed in two sessions about 10 years apart, to see what role positive factors played in their health.
They focused on "what to do rather than what not to do," according to their study published in the current PloS ONE, an open access science journal.
Genes Play a Role in Body Shapes but Don't Have the Last Word
"On average," they reported, "functional health declined significantly over the eight to 10 years, and, as expected, the declines were greatest in later life."
Yet they also found that those who took a more positive approach to life experienced far less decline.
The researchers looked at three main "factors." Strong social ties and physical exercise turned out to be highly effective in delaying the decline, but the keystone is an attitude that psychologists call "control beliefs."
"Beliefs about control include expectancies about the responsiveness of the environment and one's own abilities to negotiate it and bring about desired outcomes," Lachman said via e-mail.
That's a huge factor because if someone doesn't believe that he or she is in control of his or her own destiny, why try to do anything?
Why get off the couch if your genes have already determined that you are going to be fat? Someone who believes in control is likely to recognize that genes play a role in body shapes but don't necessarily have the last word.
'Control Beliefs' Decline as We Age
But those kinds of beliefs are formed very early in life and are very difficult to change. Someone who is optimistic about life as a child is likely to still be upbeat in later life. Lachman argues though that while such beliefs may be embedded in who we are, they are not impossible to modify.
"Such beliefs are learned through experience and they are more malleable than personality traits," said Lachman, who directs Brandeis' Lifespan Development Psychological Laboratory. "There are individual differences, with some more likely to believe little can be done and others believe they are mostly responsible for what happens."
Such beliefs are probably not constant throughout life, depending on specific circumstances, she added. It's one thing to believe that exercise can make you healthier, and quite another to believe you're going to maintain a perfect grade-point average, or marry a starlet, or become the next president of the United States. One controls personal destiny only so far.
Furthermore, "control beliefs" decline as we age, Lachman noted, partly because "there are more constraints as we get older."
A Positive Outlook Is Critical for Good Health, Study Shows
The researchers found that if even one of the three factors they studied is put to work, it makes a difference. But if all three are exercised, the difference is much greater.
"Among older adults who had all three protective factors at adaptive levels, their functional health was more comparable with the level of those in the younger and middle-aged groups," the study concluded.
The researchers believe they are the first to look at all three factors combined (control beliefs, social ties, exercise) but others have found similar results, suggesting that we really can make a difference by doing what's right, not just avoiding what's wrong.
Positive outlook turned out to be critical for good health in a large study of 2,432 older Canadians. Of course, the seniors who "thrived" also had no chronic illnesses, never smoked, drank alcohol only in moderation, and had an income of more than $30,000.
Rewarding Marriages Produce Less Stress, Better Health
But those who ended up in the best health also were significantly upbeat, according to Mark Kaplan, lead author of the study and professor of community health at Portland State University.
And psychologist Janice Kiecolt-Glaser of Ohio State University zeroed in on another factor studied by Lachman: strong social ties, or in this case, marriage. She studied 90 healthy newlywed couples to see how their stress levels rose or fell when discussing their relationship with their spouse. She measured levels of cortisol, a stress hormone that increases with negative emotions but not with positive emotions.
The level soared when negative words were used by either the male or the female spouse, but dropped when positive words were used. And because stress plays a key role in declining health, the study showed, a rewarding marriage produces less stress and thus better health.
Other researchers have also found evidence that marriage plays a key role not only in health but in longevity.
And, of course, some research has been a little perplexing. A Swedish study concluded that if you want to live an extra five years, take up golf. Yup, golf.
That study looked at 300,000 Swedish golfers and found that the death rate among the golfers is 40 percent lower than the rest of the population, which equates to an increased life expectancy of five years.
Of course, golfers spend hours outside, walking and taking in all that sunshine, so the root cause of the difference would seem to be the simple fact that golfers get more exercise.
The lead author of the study noted, however, that golfers with low handicaps had the best death rates of all, so it must be the game, not the exercise.
But I hope nobody never measures my level of cortisol when I'm trying to play that wicked game.