Aerobic exercise may reduce the risk of dementia, researchers say

The researchers broadly defined exercise as enough aerobic physical activity to raise the heart rate and increase the body's need for oxygen. Examples include walking, gym workouts and activities at home such as shoveling snow or raking leaves.

"We culled through all the scientific literature we could find on the subject of exercise and cognition, including animal studies and observational studies, reviewing over 1,600 papers, with 130 bearing directly on this issue. We attempted to put together a balanced view of the subject," says J. Eric Ahlskog, M.D., Ph.D., a neurologist at Mayo Clinic. "We concluded that you can make a very compelling argument for exercise as a disease-modifying strategy to prevent dementia and mild cognitive impairment, and for favorably modifying these processes once they have developed." The researchers note that brain imaging studies have consistently revealed objective evidence of favorable effects of exercise on human brain integrity. Also, they note, animal research has shown that exercise generates trophic factors that improve brain functioning, plus exercise facilitates brain connections (neuroplasticity).

More research is needed on the relationship between exercise and cognitive function, the study's authors say, but they encourage exercise, in general, especially for those with or worried about cognitive issues.

"Whether addressing our patients in primary care or neurology clinics, we should continue to encourage exercise for not only general health, but also cognitive health," Dr. Ahlskog says.

Co-authors include Yonas Geda, M.D.; Neill Graff-Radford, M.D.; and Ronald Petersen, Ph.D., M.D.