Regular Exercise May Help Stave Off Dementia, Alzheimer's 

THE QUESTION With the number of Americans diagnosed with Alzheimer's expected to more than quadruple to 16 million in the next four decades, people are searching for ways to prevent the disease. Might exercise help?

THIS STUDY followed 1,740 people who were older than 65 and had normal mental functioning. During a six-year period, 158 of them developed dementia, including 107 cases of Alzheimer's. Based on cognitive tests and records of physical activity (such as walking, bicycling, aerobics and swimming), those who exercised for at least 15 minutes three or more times a week at the beginning of the study were 32 percent less likely to have any type of dementia, and 31 percent less likely to have Alzheimer's, than were those who exercised less often. People who were in the worst physical condition at the beginning of the study benefited the most.

WHO MAY BE AFFECTED BY THESE FINDINGS? Older people. One in 10 people over age 65 and about half of those over 85 have Alzheimer's.

CAVEATS Exercise data, which considered the frequency of exercise but not its intensity, came from records kept by the participants and was gathered only at the start of the study. The authors wrote that the findings suggest that exercise does not prevent but may delay the onset of dementia.

FIND THIS STUDY Jan. 17 issue of the Annals of Internal Medicine; abstract available online at http://www.annals.org.