1. Work up a sweat

People who are physically active are more likely to keep their minds sharp. Regular physical activity also can help improve balance, flexibility, strength, energy and mood. Research suggests that exercise may lower the risk of developing Alzheimer's disease.

For most adults, the Department of Health and Human Services recommends at least 150 minutes a week of moderate aerobic activity, such as brisk walking. Or it recommends at least 75 minutes a week of vigorous aerobic activity, such as jogging. It's best to spread this activity throughout the week. If you don't have time for a full workout, try a few 10-minute walks during the day.