Bone-morphogenetic protein, or BMP, is found in the brains of laboratory mice and throughout the body and keeps brain stem cells from dividing into additional stem cells or baby neurons that make one more alert, and more quick to learn and remember. At Northwestern University’s Feinberg School of Medicine in Chicago, exercise was found to possibly decease BMP levels in mice. Noggin a brain hormone which inhibits BMP activity, had similar effects as exercise. Exercise may increase Noggin levels or decrease BMP levels. there is a concern that too much exercie, low levels of BMP or high levels of Noggi, may not regulate stem cells enough. But stem cells seem to wear themselves out if too many or too active. More neurons are not formed. Further studies are needed.
Find out more by reading the New York Times article Phys Ed: Your Brain on Exercise by Gretchen Reynolds. at http://well.blogs.nytimes.com/2010/07/07/your-brain-on-exercise/or by looking up BMP and other key words at www.pubmed.gov.