What effects does exercise have on the mind? What are the implications for older adults?

One of the most important findings about neurological development in recent years is that the brain retains some plasticity, the capacity to grow and change, throughout life. Physical health is associated with neurological health and plasticity throughout adulthood. More physically fit and active older adults tend to show greater brain volume and more efficient activity in areas key to memory and abstract thought. Moreover, exercise training, particularly aerobic exercise, is associated with increases in brain volume and cognitive function, especially executive function in older adults.
Cardiovascular exercise and activities that improve coordination are associated with increases in volume and connectivity in the frontal cortex, temporal lobe, and the hippocampus, areas responsible for memory and higher level cognitive functioning, such as planning, and problem solving, and prone to age-related deterioration. Aerobic exercise is associated with neurogenesis, the creation of new neurons, in the hippocampus and prevents age-related atrophy in this area. Exercise also protects the brain through its positive effect on cardiovascular health, reducing the likelihood of stroke, and increases blood flow to the brain, which protects brain function.
Older adults who begin program of moderate aerobic exercise show improvements in brain function and cognition. In one study, greater amounts of physical activity were associated with greater gray matter volume in several areas of the brain including the prefrontal cortex and hippocampus over a 9-year period and a reduced risk for cognitive impairment. Moreover, even sedentary older adults introduced to a long-term program of moderate physical activity show increases in hippocampal volume over a 2-year period, suggesting that it is never too late to improve physical and neurological function. Changes in fitness levels and hippocampal volumes are associated with improvements in recognition and spatial memory. These exercise experiments demonstrate that the brain remains modifiable throughout adulthood and that aerobic exercise offers important opportunities for neural plasticity.