Q. Okay, Doc. I know I was born with a good brain. But I don’t get this emphasis on “challenging mental stimulation” and some of the other stuff you talk about. What’s the “real deal” here?

A. I’m glad you recognize you were “born with a good brain.” I regret it apparently hasn’t kept up with the latest brain-function research. I suggest a computer metaphor. Picture you were born with brain hardware and some software. As you grow and develop, the software is regularly updated (just like it is in the real computerized world). As your brain hardware ages, however, studies have shown how critically important it is to include exercise on a daily basis. Physical exercise―because it is one of the most important things you can do to keep your brain healthy. And mental exercise―because it is associated with not only retaining your “marbles,” so to speak, but also with potentially slowing the onset of symptoms of aging. The current recommendation is a minimum of 30 minutes of challenging mental exercise on a daily basis, plus reading aloud for 10 minutes a day.