Every walk around the block, every dumbbell curl, every yoga pose -- each is a good investment in your mind.

Time and time again, research has shown that if you keep your body busy today, your brain is less likely to suffer from memory thieves like Alzheimer's and other forms of dementia tomorrow. Why is exercise so important? It boosts cerebral blood flow and stimulates the growth of new gray matter. Maybe bodybuilding should be called brain building.

No single type of exercise has an edge in protecting your brain. Studies have found cognitive benefits from aerobic exercise (brisk walking, biking, raking leaves) as well as from strength and flexibility workouts, such as lifting weights and holding yoga poses; they all provide long-term protection. Even activities that you probably don't think of as "exercise" count, including picking up your niece's favorite toy for the umpteenth time, doing three loads of laundry while waiting for the cable company, or pacing the floor as you watch your team lose in overtime. What else can you do to keep moving?