Study shows why exercise boosts brainpower:
Tests on mice showed they grew new brain cells in a brain region called the dentate gyrus, a part of the hippocampus that is known to be affected in the age-related memory decline that begins around age 30 for most humans.The researchers used magnetic resonance imaging scans to help document the process in mice — and then used MRIs to look at the brains of people before and after exercise.
They found the same patterns, which suggests that people also grow new brain cells when they exercise.