People at higher genetic risk for Alzheimer’s disease may be able to offset that propensity by exercising, according to a new observational study at Washington University in St. Louis.

Researchers used PET scans to image the brains of 163 participants, ages 45-88, who tested normal on a test for cognitive decline. They identified 52 as carriers of APOE epsilon-4, a genetic risk factor for Alzheimer’s. Among sedentary APOE epsilon-4 carriers, the scans showed greater buildup of amyloid plaques in the brain associated with the development of Alzheimer’s.

But the carriers who were physically active, meeting the American Heart Association guidelines for regular exercise, showed no more buildup of amyloid plaques than found in the brains of non-carriers.

Although the study wasn’t designed to prove cause and effect, the scientists noted that the genetic risk “makes beneficial lifestyle factors, such as exercise, preferentially important.” – Archives of Neurology