Boomers beware: Know when to see doctor

CHICAGO (AP) -- When it comes to athletics, even the fittest baby boomers are finding aging bodies aren't as nimble as young ones, and they're more prone to minor damage that can turn serious if ignored.

Knee replacements have more than tripled in people aged 45-64 in recent years, and a study released last week found nearly 1 in 20 Americans older than 50 have the artificial joints.

Dr. Steven Haas of the Hospital for Special Surgery in New York City says people shouldn't abandon exercise because it has many health benefits. But, they should make sure they're well-conditioned and listen to their bodies.

Hans says switching to less rigorous activities is sometimes the answer: "If your knee is killing you every day after you run, you're probably not doing the right sport."