Physical activity and the maintenance of cognition: learning from animal models.

Although exercise has long been equated with better physical health, there is now extensive research showing that it has substantial benefits for the brain as well. From an Alzheimer's disease (AD) standpoint, one of the most important effects of exercise is on cognition. Exercise not only improves cognitive function in normal individuals, but it has been associated with a lower risk for AD and other types of dementia. Studies in animal models also suggest that exercise might attenuate some of the cognitive symptoms and pathophysiology of dementia. Recent research has attempted to identify molecular and cellular changes in the central nervous system elicited by physical activity. Work in animal models has identified several key responses, including up-regulation of growth factors, increased neurogenesis, and improved learning and memory, which might be key to improved cognition in response to exercise.