In addition, physical activity was associated with increased total brain volume, particularly of the hippocampus, which is involved in short-term memory. One way that exercise may benefit the brain is by boosting cerebral blood flow, which declines with aging. “The brain is a highly metabolic organ that accounts for 20 percent of the oxygen and 25 percent of the glucose consumed even though it is only 2 percent of body weight, which makes it particularly vulnerable to alternations in blood flow,” the researchers noted.

More support for exercise comes from an analysis of 10 high-quality studies, published in Mayo Clinic Proceedings in August 2016. It concluded that people in their seventies or eighties who engage in regular physical activity “seem to have a 40 percent lower chance of developing Alzheimer’s disease than their physically inactive peers.”