Physical activity and mental stimulation are both considered vital for protecting your mental skills and warding off dementia. But is one activity more effective than the other? "It is difficult at this point to say, because most studies have not addressed this specific question," says Dr. Scott McGinnis, an instructor in neurology at Harvard Medical School.
In favor of physical activityA recent study of people in their 70s published in Neurology found that those who exercised the most had the least brain shrinkage and fewer white matter brain lesions, which can be signs of dementia. People who engaged in intellectual activities didn't have the same benefits. But the results came from the analysis of questionnaires followed by brain scans a few years later, and Dr. McGinnis says that's not enough evidence to eliminate mental stimulation as a cognitive protector. It does, however, support exercise's role in protecting brain health, as does another study published recently in Stroke, which found older adults who exercised regularly reduced their risk of vascular-related dementia by 40%.
Dr. McGinnis says many studies have shown consistently that regular exercise can increase the volume of brain regions important for memory and thinking. "There are a number of possible mechanisms for this," he says, "such as stimulating production of growth factors, blood vessels, and new brain cells, which may provide a buffer against brain changes that cause dementia."
In favor of mental activityThere is also abundant evidence that mental activity maintains cognitive health. Two studies in 2012 reaffirmed this. One study, published in Neurology, found a direct link between the amount of cognitive activity, such as reading the newspaper or playing chess, and the level of cognitive function in the following year. Another study, as we reported in Harvard Health Letter, found that engaging in meaningful activities such as volunteering or a treasured hobby promotes cognitive health in old age.
"Exercising a specific cognitive function will improve that function. If one engages in tasks requiring working memory, such as holding and manipulating material in mind for short periods of time, one will usually become stronger in that area," says Dr. McGinnis.
What you can doTake advantage of the cognitive protection from both mental and physical activities. To get physical benefits, start moving. "A modest amount of aerobic exercise is sufficient to produce positive cognitive results. Many studies have employed regimens of moderate-intensity walking three days a week," says Dr. McGinnis.
For mental activity, he suggests doing something you already enjoy. "It might be crossword puzzles, reading, participating in a club, building models, or any number of activities. The guiding principle is that activities require active engagement, not passive engagement such as watching television. I certainly recommend physical, mental, and social activity for nearly all of the patients I see in my cognitive neurology clinic."