Can regular exercise help prevent Alzheimer's disease and dementia?

Working out for as little as 15 minutes three days a week reduces the risk of dementia and Alzheimer’s by 40%. A six-year study determined that men and women age 65 and older dramatically lessened their chances of developing the heartbreaking conditions of dementia and Alzheimer’s by regularly exercising.

Several studies suggest that exercise might help ward off Alzheimer's disease and other forms of dementia. A six-year study of 1,740 people ages 65 and older found that people who exercised more than three times a week had a lower risk of dementia than their sedentary counterparts, according to a study in Annals of Internal Medicine.

Even people who already have early signs of memory problems may benefit from physical activity. In a study in Journal of the American Medical Association (JAMA), people in their 50s and older who reported memory problems but did not have dementia were assigned to follow either a home-based exercise program or to receive education and usual care for six months. The exercisers were asked to do at least three 50-minute exercise sessions a week. (Most walked; some did other aerobic exercise or strength training.) At the end of the 18-month follow-up, the exercise group showed modest improvements in cognition.