5. Sweat at the Fountain of Youth.

Why it matters: Increasing snowdrifts of studies point to the same conclusion: Among all other lifestyle factors, movement is the linchpin to good health. People who exercise regularly have a lower risk of developing cardiovascular diseases, dementia, diabetes, depression, and osteoarthritis. They're also more likely to maintain a stable, healthy weight and less likely to be obese, which is itself a risk factor for those diseases.

Now a series of compelling independent studies published in an early 2010 issue of the Archives of Internal Medicine underscores the message that exercise can stave off many diseases. An analysis from the large Nurses Health Study, for example, found that women who jogged three hours a week or walked briskly for five hours a week were 76 percent more likely to age successfully, with less chronic disease or mental impairment, an effect that held among all ages and weights.

What to try: Rethink your idea of "exercise" as "movement" of all kinds. Aim for a three-way mix of aerobic exercise (such as walking and running) for the heart, lungs, and circulatory system; resistance training (with free weights, weight machines, or exercises such as squats and lunges) for muscular and bone strength; and balance work (such as tai chi or yoga) for bone density and overall strength.

If you're currently an exercise abstainer, start small. Research shows you can add exercise at any age, even your 60s, 70s, and 80s, to reap benefits. Take the stairs instead of the escalator or elevator. Park at the far end of a parking lot instead of cruising until a spot near the entrance opens up. Build up gradually.

Karin Richards, director of the exercise science and wellness management program at the University of the Sciences in Philadelphia, suggests a "sing/talk test" as a way to gauge your intensity. "If your pace is meeting your target heart rate, you should be able to talk without being breathless," she says. "If you can't catch your breath to talk, your exercise intensity is too great. If you can sing while you exercise, it's not vigorous enough."