Ladies, Take a Walk on the Wise Side
"A little walking is good, and more is even better," says Kristine Yaffe, MD, assistant professor of psychology, neurology, and epidemiology at the University of California, San Francisco and chief of geriatric psychiatry at the San Francisco VA Medical Center
Yaffe and colleagues looked at nearly 6,000 women aged 65 and older who had no signs of impaired mental or physical abilities. The women were tested for mental function at the beginning of the study and again 6-8 years later.
The researchers found that women who walked the most were the least likely to suffer a decline in thought processes and that there was a direct relationship between activity and mental function: As the amount of walking or calories burned per week rose, the risk for loss of mental abilities declined.
"We found that for every extra mile walked per week there was a 13% less chance of [mental] decline," Yaffe says. The most active women in the study walked an average of about 18 miles per week; the least active made it barely half a mile.
To account for possible differences among the study participants that could skew the results, the researchers massaged the data to compensate for the fact that the more active women in the study tended to be younger, had more years of higher education, and had fewer medical problems than inactive women.
The protective effect of exercise held up even when these differences were taken into consideration, Yaffe says.
The study adds to the growing body of evidence that even modest amounts of physical activity can have a visible health benefit. A Harvard University study published in TheJournal of the American Medical Association earlier this year found that women who walk as little as about one hour per week have about half the risk of heart disease as women who don't get off their sofas.
"As the U.S. population is growing older, there is interest now in how we can live so that we improve our functional capacity well into older age, and not just our physical capacity but our mental capacity, and what they're seeing with regard to [mental] function adds to that body of evidence that physical activity may play an important role," says I-Min Lee, MBBS, ScD, associate epidemiologist at Brigham and Women's Hospital and associate professor of medicine at Harvard Medical School in Boston. Lee, who headed the study, commented on the new findings for WebMD.