15 ways to live longer

It's been said that a man dies simply because he doesn't know how to live longer. Well, thank goodness for progress.

People are living longer these days. According to the Centers for Disease Control, in 1920 the average life expectancy was 54. Today, people can expect to live to 78.

Feel free to speculate about why — better food supply, better medical care, better hygiene or any number of other factors. It's not totally clear to scientists how they all add up. But what we do know is that studies are finding genetics don't tell the whole story when it comes to which diseases will likely kill us. "There's a saying that genetics load the gun, but it's the environment that pulls the trigger," says Dr. David Fein, medical director at the Princeton Longevity Center, a clinic in Princeton, N.J., which focuses on quality of life and prolonging it. "You can have the gene for a certain disease, but it doesn't mean you're going to get it."

Take heed: Your lifestyle choices are very significant. While there is no way to ultimately defy death, that isn't an excuse to start indulging in vices and neglecting your health. There are plenty of ways to keep the grim reaper at bay — and many of these "secrets" result in an improved quality of life.

If you really want to live longer, then start with your attitude. Your way of thinking not only improves your outlook on life, but also how long you actually live. In 2002, researchers at the Mayo Clinic in Rochester, Minn., found that optimistic people decreased their risk of early death by 50 percent compared with those wholeaned more toward pessimism.

15 ways to live longer