Train your body to stay young

Next time there's a marathon in your area, take a good look at the competitors and see if you can spot who's running in the 65+ category.

It's not as easy as it sounds, it requires heavy endurance training.

Some of these seniors look 10, 20, or even 30 years younger than they really are -- and the difference isn't just on the outside.

They're younger on the inside, too.

In a recent series of experiments, researchers compared the DNA of seniors who are endurance training for events such as running and cross-country ski races to the DNA of healthy seniors who are not as athletic.

It didn't take long to spot the difference: Seniors in training have longer telomeres.

If you haven't heard of telomeres yet, you will soon. They're little caps on the tips of your DNA, and they're at the cutting edge of anti-aging research.

The older you are, the shorter they get -- and when they reach the end, you might say you're reaching your end, too. It's the closest thing you have to an expiration date in your body -- but as the new study shows, it's one you can extend through healthy activities such as endurance training.

Interestingly, the researchers didn't find the same link between telomere length and endurance training in people in their 20s -- but it may be because younger people simply haven't been training long enough to get the benefit.

Or it could be that since younger people already have longer telomeres naturally, the effect of endurance training won't be as noticeable as it is in seniors.

Either way, all the research on telomeres points in the same direction: As you get older, it's more important than ever to do what you can to stop your telomeres from shrinking.

In addition, the omega-3 fatty acids in fish oil can help slow telomere shrink -- and in one study I told you about recently, they were shown to actually help telomeres to grow longer.

Since too much seafood can expose you to high levels of mercury, the best source of omega-3 fatty acids these days isn't fish. It's a purified fish oil supplement from a maker you trust.