Forget the fit body _ what about a fit brain?

New research is suggesting that whatever exercise does for one's physique, there's a benefit we're understanding only now: exercise makes us smarter.

This isn't just about exercise making us feel perkier and better able to focus. This is about the brain performing at a higher, better level, over time, in people who work their bodies.

So Newsweek just revealed in "Stronger, Faster, Smarter" by Mary Carmichael. She looked at the work of researchers like Dr. Charles Hillman, a neuroscientist at the University of Illinois. He and other scientists are discovering that brawn leads to the brain. And so in a study of grade-school students, for instance, he found that the most fit kids also did the best on statewide standardized tests, "even when factors such as socioeconomic status were taken into account."

Just a few weeks ago, "researchers announced that they had coaxed the human brain into growing new nerve cells, a process that for decades had been thought impossible, simply by putting subjects on a three-month aerobic-workout regimen." There are also growing indications that physical activity can stave off Alzheimer's disease.

We've known for a long time that exercise sends blood to the brain, and that has benefits. What's new? Well, as Carmichael lays it out, a lot. There's new understanding that a chemical that's produced with exercise, BDNF, "fuels almost all the activities that lead to higher thought." Harvard psychiatrist John Ratey calls the molecule "Miracle-Gro for the brain." Conversely, a brain that's low on the Miracle-Gro "shuts itself off to new information," as Newsweek put it.

Unfortunately, the kind of exercise I do _ intense, slow weightlifting _ may be great for strengthening thighs, but unfortunately it isn't the most helpful for the brain, and no one knows why. Does running after four kids count? But at least it's something.

Believe me, I'd drive myself to the bathroom if I could. Let's just say that given how often I can't seem to recall a name or find my car keys, I shudder to think where I'd be if I didn't exercise at all. Continued...