Exercise is much like calorie restriction in that there are few aspects of aging not improved by its practice. From RedOrbit: a review of research "finds that consistent aerobic exercise can prevent age-related decline in brain function, and may even help reverse aging of the brain. ... Moderate physical exercise, at a level that would make a person breathless, has been shown to increase both the speed and sharpness of thought in people with or without signs of Alzheimer's disease or dementia. Furthermore, exercise has also been shown to improve the volume of brain tissue and the way in which the brain functions ... These results suggest that regular aerobic exercise [can] reliably reverse age-related cognitive decline ... many questions remain unanswered [about] the effect of exercise on the brain. However, [we] can safely argue that an active lifestyle with moderate amounts of aerobic activity will likely improve cognitive and brain function, and reverse the neural decay frequently observed in older adults."

Link: http://www.redorbit.com/news/health/1590207/aerobic_exercise_may_slow_reverse_agerelated_brain_decline/