Physical exercise has a protective effect on the brain and its mental processes, and may even help prevent Alzheimer's disease. Based on exercise and health data from nearly 5,000 men and women over 65 years of age, those who exercised were less likely to lose their mental abilities or develop dementia, including Alzheimer's.

Furthermore, the five-year study at the Laval University in Sainte-Foy, Quebec suggests that the more a person exercises the greater the protective benefits for the brain, particularly in women.

Inactive individuals were twice as likely to develop Alzheimer's, compared to those with the highest levels of activity (exercised vigorously at least three times a week). But even light or moderate exercisers cut their risk significantly for Alzheimer's and mental decline.

Intelligence at Any Age
Since 1956, the Seattle Longitudinal Study has tracked more than 5,000 people, aged 20 to 90 years old. When participants began to experience cognitive decline, they were given a series of five one-hour training sessions designed to improve inductive reasoning and spatial orientation.

As a result, half of them improved significantly — demonstrating that mental enrichment increases fluid intelligence at any age. Lead researcher of the study, Dr. K. Warner Schaie, concluded: "The results of the cognitive training studies suggest that the decline in mental performance in many community-dwelling older people is probably due to disuse and is consequently reversible."