Physical Fitness Keeps Older Minds Sharp

Staying physically fit is not only good for your body, it also seems to help keep your mind in good shape, new study findings show.
 
Researchers found that adults who were most fit at the start of a six-year study maintained their mental sharpness over time and did better in tests of their mental function conducted years later than did their less physically fit peers. "Physical activity appears to be good for the brain as well as the body," study author Dr. Deborah E. Barnes of the VA Medical Center in San Francisco, California, told Reuters Health. "Older adults with higher levels of cardiorespiratory fitness experience a slower rate of cognitive decline over time," she added.

Cardiorespiratory fitness describes the heart's and lungs' efficiency in processing oxygen, Barnes explained. "People who are not very fit have difficulty processing oxygen when they exercise -- that is why they get 'winded' or have difficulty breathing," she said. Previous studies have shown that adults with low levels of physical fitness are likely to experience more mental decline over time than their more active peers, but those studies relied on the participants own self-reports of activity, the researchers note. Other studies that have detected an association between cardiorespiratory fitness and better mental function have been poorly designed or did not include many older individuals.

In the current study, the researchers again used cardiorespiratory fitness -- determined by the adults' performance during a standard treadmill-based exercise test -- because it is largely determined by habitual physical activity, and may therefore give more accurate information than adults' self-reports of physical activity, they note. The participants' mental function was evaluated with a test that measured their ability to register and recall words, follow instructions and their orientation to time and place.

At the start of the study, which included 349 adults aged 55 and older, none of the participants had any symptoms of cardiovascular disease, physical disability, or mental impairment. Adults who were the most fit at the start of the study exhibited the least amount of mental decline, Barnes and her colleagues report in the Journal of the American Geriatrics Society. For example, their scores on the mental state examination at follow-up were similar to their scores at the start of the study. Their least physically fit peers, in contrast, scored lower on the mental state exam by follow-up, and performed lower on other tests of their mental function, such as remembering fewer words during the word recall test than their peers.

Several explanations exist for why fitness may be associated with better mental function in older adults, the researchers note. Cardiorespiratory fitness may reduce a person's risk of cardiovascular disease, high blood pressure, diabetes and other conditions known to be associated with poor mental function in older adults, they speculate. Or, cardiorespiratory fitness may be directly associated with blood flow in the brain, reductions in which have been linked to lower mental function in both Alzheimer's disease patients and normal older adults.

In a related editorial, Dr. Eleanor M. Simonsick of the National Institute on Aging and Johns Hopkins University School of Medicine in Baltimore, Maryland, writes that the study "represents a shift in the right direction for studies examining physical activity, fitness and cognitive function." She cautions, however, that the long-term association between fitness and mental function does not necessarily mean that differences in physical fitness are the cause of the differences in mental function. More study is needed, Simonsick concludes.

In the meantime, Barnes advised that "older adults who are already active should keep exercising," and those who are inactive "should consider beginning an exercise program, ideally in consultation with a physician."

 Grants from the National Institute on Aging and an award from the National Institute of Mental Health funded the research.

SOURCE: Journal of the American Geriatrics Society 2003;51.  Email Story

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Power of Positive Thinking Extends, It Seems, to Aging

Do happy people live longer? A growing body of evidence suggests they may. Recent studies have correlated long life with optimism, with positive thinking, and with a lack of hostility, anxiety and depression.

One thing that remains unclear, however, is whether happiness can actually cause longevity. Perhaps happy people live longer because they practice healthy behaviors, or for some other unknown reason.

"It is definitely the case that certain people who are psychologically healthier live longer," said Dr. Howard S. Friedman of the University of California at Riverside, a psychologist who has studied personality traits that correlate with longevity. "But the explanations are usually complicated."

The second open question is: What, if anything, can unhappy people do about it?
The most recent study of personality and longevity was conducted among a group of 660 people over 50 in Oxford, Ohio, who, in 1975, had answered questions having to do with, among other things, their attitudes about aging. They had been asked whether they agreed or disagreed with statements like "Things keep getting worse as I get older," "I have as much pep as I did last year," and "I am as happy now as I was when I was younger."

Researchers checked to see which participants were still alive in 1998, and they noted when the others had died. It turned out that those who viewed aging as a positive experience lived, on average, 7.5 years longer than those who took a darker view.
That is an advantage far greater, the researchers point out, than what can be gained from lowering blood pressure or reducing cholesterol, each of which has been found to lengthen life about four years. It also beats exercise, not smoking and maintaining a healthy weight, strategies that add one to three years.

The researchers who conducted the study have been careful not to suggest that views of aging are more important for one's health than exercise, nutrition and not smoking. "I think they are all important in predicting survival," said Dr. Becca Levy, a social psychologist at Yale. But, Dr. Levy said, it is surprising to find that a psychological characteristic could also be such a strong predictor of life span.

In analyzing the data, Dr. Levy and her colleagues took into account race, sex, socioeconomic status, self-reported health, overall morale and loneliness — all factors that might have clouded the picture. But even after statistically controlling for such characteristics, views of aging were highly correlated with long life.

Optimism was linked to longevity in a study reported two years ago by researchers at the Mayo Clinic in Rochester, Minn. Dr. Toshihiko Maruta, a psychiatrist, reviewed psychological tests that had been given to more than 800 people in the early 1960's, and based on the people's responses, he classified 197 of them as pessimistic. He then checked to see how long they lived.

Dr. Maruta found that the pessimists had a risk of death for any given year that was 19 percent greater than average.

Other studies have drawn connections between longevity and the degree of control people feel over their lives and between longevity and mindfulness, defined as an awareness of one's environment and one's reactions to it. Some research has shown that people who are relatively more depressed, hostile or anxious are unlikely to live as long as others.

Dr. Carolyn Aldwin, a professor of human and community development at the University of California at Davis, has reviewed many such studies and examined another group of people who took psychological tests in the 1960's. She found that those who seemed to be relatively stable emotionally had lived longer.

"You're better off if you are less likely to go to extremes emotionally," Dr. Aldwin said, "if you keep on an even keel and don't let yourself get too upset."

How do happy, upbeat, calm people keep themselves alive?

Dr. Levy suspected that the answer might be linked to the positive thinkers' will to live. Previous studies showing, for example, that people of all cultures are more likely to die in the days and weeks after holidays than they are in the days leading up to them, had suggested that will to live could affect survival.

So Dr. Levy and her colleagues checked back to see how the respondents had answered other questions in the original survey. In these, they had been asked to choose from three pairs of adjectives — empty-full, hopeless-hopeful and worthless-worthy — the ones that best described their lives. Those who answered full, hopeful and worthy were deemed to have the greater will to live

"Will to live appeared to be a partial mediator," Dr. Levy said, "but it didn't completely explain why the people with positive views lived longer. So there must be other things involved. One likely candidate is how people respond to stress. Older people with a negative view of aging."

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