Staying mentally fit requires the same approach you would take to keep any muscle fit: exercise! You can exercise your brain in a multitude of ways, including reading, doing crossword puzzles or logic puzzles and studying a new language.

This does not always have to be a serious or scholarly effort. Recent research using imaging studies demonstrated increased activity and connections in the brains of people over age 50 who learned to juggle in a three-month class. The catch? The positive effect on their brains lasted only as long as they kept practicing their newfound skills.

Talk, Talk, Talk

Spending as little as 10 minutes a day talking to another person can boost memory and test scores, two ways that researchers measure mental abilities. In fact, University of Michigan researchers showed that a brief chat was just as effective as spending 10 minutes on a crossword puzzle. Both activities proved more effective at boosting brain power than watching television for 10 minutes, however.

Socializing offers more benefits than better test scores, of course. Recent studies have shown that people who maintain an active social network also seem to live longer and enjoy a higher quality of life. Successful relationships continually hone the mind's sharp edges by giving people the chance to interact and learn new things about other human beings.

Keeping Blood Pressure Low

One in three adults in the United States has high blood pressure, which is also called hypertension. High blood pressure damages the blood vessels and increases the risk of strokes, which contribute to mental decline. Keep your blood pressure below a reading of 120/80 mm/Hg using medication, diet and exercise and by making such other lifestyle choices as drinking less alcohol and giving up cigarettes.

Sleep for a Fit Brain

Recent research suggests that sleeping too much or too little might also increase the risk of a stroke, which is a significant concern for long-term brain health.

Researchers are just beginning to untangle the complicated relationship between sleep and long-term mental abilities. Almost everyone has had the experience of feeling a little less sharp after a bad night's sleep, but the data suggest that interrupted sleep patterns are more closely associated with an increased risk of dementia than previously thought.

If you have trouble sleeping through the night, talk to your doctor or a neurologist.