Ever wonder why you can’t remember the name of the person you met ten minutes earlier? It could be you weren’t paying attention. Or, it could be your dentate gyrus:

Researchers from four universities report in the Annals of Neurology that people who absorb glucose more slowly than those who metabolize it quickly are more forgetful and are more likely to have a faulty dentate gyrus, a pocket in the hippocampus section of the brain…

The dentate gyrus’s exact function is unknown. But it’s one of several circuits in the hippocampus that, if disrupted, impairs memory, such as a person’s ability to learn the names of new people or to remember where they parked their car.

The possible connection between its dysfunction and poor glucose regulation may explain earlier observations that exercise benefits the dentate gyrus, Small says. Until now, scientists believed that physical activity reduced the risk of age-related memory loss by allowing glucose to be absorbed more quickly into muscle cells, but were not sure why. This indicates, Small says, that the dentate gyrus could be the missing link. [From Scientific American – Exercise and your brain: Why working out may help memory by Jordan Lite.]

As I’ve written in the past, exercise may not be a magic bullet for maintaining and enhancing cognitive function, but there’s a lot of research showing how valuable physical fitness is to brain fitness. See also Fitness Marketers Need to Get Brainy. John Medina’s Brain Rules devotes a chapter to the topic of exercise and the brain. And, it’s more than a year old now, but Newsweek did an in-depth article on the subject titled Stronger, Faster, Smarter.