President Bush today told Americans to get off the couch and exercise because it’s good for the body and mind. Unless he was reading LiveScience earlier today, he probably didn’t know how right he was.

Swedish researchers announced today that exercising mice grew new brain cells. Mice function similarly to humans, so the scientists figure this might explain why exercise works so well as an anti-depressant, something fit folks have long known. After all, what could be more uplifting than new brain cells for an old brain?

So do what your president says, and more:

Another study out today strengthens the case that mental exercises, from reading to attending a play, help stave off Alzheimer’s.

While genetics, modern medicine and luck all play roles in our well-being, it’s clearer than ever that a little mountain biking (perhaps while reading the newspaper) goes a long way. Don’t suggest that to Mr. Bush, however.