Exercise or play is vital to brain health and here is another reason why.

"It appears that if a cell is not appropriately stimulated by other cells, it self-destructs," Dr Coulson said. This self-destruct process is also known to be an important factor in stroke, Alzheimer's and motor neuron diseases, leading to the loss of essential nerve cells from the adult brain.

Challenge yourself and stimulate your brain by writing with your left hand (if you're right handed), learn a new hobby, and incorporate balancing on one foot while you do simple tasks like tyeing your shoes, showering, or cleaning the house.

U.S. News and World Report has a great article and video here.