Here’s more evidence that walking is good for the brain. Specifically the hippocampus — a part of the brain important to the formation of memories — It usually begins to atrophy around 55 or 60. Now psychologists are suggesting that the hippocampus can be modestly expanded, and memory improved, by nothing more than regular walking.

Researchers randomly assigned 120 healthy but sedentary men and women in their 60”s to one of two exercise groups. One group walked around a track three times a week, building up to 40 minutes at a stretch; the other did a variety of less aerobic exercises, including yoga and resistance training.

After a year, brain scans showed that among the walkers, the hippocampus had increased in volume by about 2 percent on average; in the others, it had declined by about 1.4 percent. Since such a decline is normal in older adults, the researchers say a 2 percent increase is fairly significant. Both groups also improved on a test of spatial memory, but the walkers improved more.

The researchers were delighted to learn that the hippocampus might expand with exercise - and it didn’t take that much. The study is published in The Proceedings of the National Academy of Sciences.