New research is showing some of the molecular reasons why keeping fit also keeps you sharp, and it has to do with your brain’s untapped potential for growth.
Dr. Fred Gage and collaborators have been publishing a variety of papers describing the molecular pathways by which exercise leads to brain growth. Gage’s work in the 90’s showed that our brains have a store of stem cells that lie largely dormant, waiting for some stimulus to initiate cell division. A growth factor called bone morphogenetic protein (BMP) works to control cell division throughout the body, including in the brain. The more BMP, the less growth. Regulatory factors like BMP are essential to a healthy body; studies have shown that the absence of BMP activity is linked to colon cancer.
But as we get older, higher counts of BMP accumulate in the brain and keep our neural stem cells asleep. This is where exercise comes in. Within one week of being given an exercise wheel, mice showed half as much BMP signaling in their brains. The mice also showed increased levels of the protein Noggin (yes, I know), which acts as a BMP-antagonist. There are still questions as to whether exercise directly decreases BMP, or does so indirectly via Noggin production. Either way, stem cells begin to divide and new neurons are born.