Physical activity has many health benefits, such as reducing falls, maintaining mobility and independence, and reducing the risk of chronic conditions like depression, diabetes, and high blood pressure. Based on research to date, there's not enough evidence to recommend exercise as a way to prevent Alzheimer's dementia or mild cognitive impairment (MCI), a condition of mild memory problems that often leads to Alzheimer's dementia.

Years of animal and human observational studies suggest the possible benefits of exercise for the brain. Some studies have shown that people who exercise have a lower risk of cognitive decline than those who don't. Exercise has also been associated with fewer Alzheimer's plaques and tangles in the brain and better performance on certain cognitive tests.

While clinical trials suggest that exercise may help delay or slow age-related cognitive decline, there is not enough evidence to conclude that it can prevent or slow MCI or Alzheimer's dementia. One study compared high-intensity aerobic exercise, such as walking or running on a treadmill, to low-intensity stretching and balance exercises in 65 volunteers with MCI and prediabetes. After 6 months, researchers found that the aerobic group had better executive function—the ability to plan and organize—than the stretching/balance group, but not better short-term memory.

Several other clinical trials are testing aerobic and nonaerobic exercise to see if they may help prevent or delay Alzheimer's dementia. Many questions remain to be answered: Can exercise or physical activity prevent age-related cognitive decline, MCI, or Alzheimer's dementia? If so, what types of physical activity are most beneficial? How much and how often should a person exercise? How does exercise affect the brains of people with no or mild symptoms?

Until scientists know more, experts encourage exercise for its many other benefits. To learn more about exercise and physical activity for older adults, visit NIA's Go4Life campaign.

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