Physical exercise is hugely important in recovering all those marbles we somehow lose during cancer treatment. Exercise increases blood flow (and oxygen) to the brain. In laboratory studies, animals that exercise regularly create new neurons in the hippocampus. That region of the brain is key to forming memories.
The brain is an amazing organ with the power to heal itself. You may have seen evidence of this in stroke victims who are able to regain many of their functions.
Confirming the benefits of exercise, there's a large study just out in the July issue of the Journal of the American Geriatrics Society that focuses on teenage physical activity. The authors conclude that exercise in the teen years reduces the risk of cognitive impairment as we age. They also look at what happens to women who are sedentary as teens and become physically active later in life (age groups 30 and 50). Those women show a significantly lowered risk of dementia as well. So if you're already exercising, good for you. If you're not, get out there, give me twenty and tone up that flabby brain.
Have you always exercised? If so, do you believe it kept the fog away (or helped lift it) during and after chemotherapy?
There's a good summary of the study in Science Daily at this link. You'll find the actual journal abstract here.
Laura E. Middleton, Deborah E. Barnes, Li-Yung Lui, Kristine Yaffe. Physical Activity Over the Life Course and Its Association with Cognitive Performance and Impairment in Old Age. Journal of the American Geriatrics Society, June 2010 DOI: 10.1111/j.1532-5415.2010.02903.x
ScienceDaily (July 1, 2010). Teenage Physical Activity Reduces Risk of Cognitive Impairment in Later Life. http://www.sciencedaily.com/releases/2010/06/100630071139.htm