The article stated that rats who ran more miles had more neurogenesis. So my guess would be walking = less distance than running = less benefit. But this is to

The article stated that rats who ran more miles had more neurogenesis. So my guess would be walking = less distance than running = less benefit. But this is too much of a simplification. If you walk a mile in 15 minutes and run a mile in 7.5, is there a difference? Maybe not, but if you run, you can then run two miles in the same 15 minutes and increase your efficiency.