Photo: mikebaird, Flickr

If your excuse for not engaging in sweat-dripping, pavement-pounding workouts is your worry about either getting or worsening your arthritis, you're in luck. A study with more than 1,200 participants found no link -- let's reiterate, that's zero, nada -- between osteoarthritis and exercise, even high-impact. And although obesity is an independent risk factor for the joint condition, physically active overweight participants fared just as well as their slim peers. The average age was in our Fit After 40 range, 53.

"What's particularly convincing about the study is they also took an MRI of each subject's knee. They discovered that those who performed the most vigorous weight-bearing exercise had the thickest, healthiest cartilage," says Dr. Harvey Simon, editor of the Harvard Men's Health Watch. What's more, these findings were consistent with another study published last year that found no connection between running and arthritis. In fact, running seemed to actually benefit joints.

In both studies, none of the members had arthritis to begin with. But other research shows that exercise at any level can even help those who already have it. "A lot of people don't exercise because they think their arthritis pain will be exacerbated but the opposite is true," says Dr. Patience White, chief public health officer for the Arthritis Foundation. So for those of you who are using your arthritis pain as an excuse not to move, listen up: "When physical activity is combined with a weight loss program, you can actually prevent arthritis pain and decrease the progression."

The bottom line: Whether you're a fitness vet or beginner, cardio at any intensity can help your arthritis. For those of you who are already doing moderate bouts and don't have a previous injury that you've got to nurse, give the higher-impact, calorie-scorching activities a go. To keep those joints healthy and prevent injury, be sure to invest in shoes that deliver shock absorption -- and never skip your warm-up, cool-down and stretches. Finally, remember you're not 25. "Listen to your body. Report any signs of discord to your doctor," says Dr. Smith.

Even if you're fortunate enough not to have arthritis, your knees are injury-prone and this is more prominent among women. Find out what steps to take to prevent knee problems.