Dear Doctors: I recently added running to my weight-loss program. Not only do I feel better, but the pounds are also coming off faster. However, I keep reading that running is bad for my knees, so it makes me wonder -- am I making a mistake?

Dr. Elizabeth Ko and Dr. Eve Glazier

We're happy to reassure you that running, when done properly, is not bad for your knees. In fact, a number of recent studies suggest the opposite is true.

In addition to a lowered risk of stroke and heart attack, runners in the studies had lower rates of osteoarthritis than the non-runners did. And thanks to the runners' general level of fitness, their chosen form of exercise was seen as beneficial to maintain joint health.

The idea that running is bad for your knees is one of those myths that just won't go away. It sounds like common sense -- you hit the ground with a certain amount of force as you run, so over the course of a few miles (or quite a few, if you're a distance runner) your knees must take a beating. But numerous studies conducted over the last decade have repeatedly shown that's not so.

Researchers found no correlation between running and osteoarthritis, also known as OA. Sure, a percentage of the participants in the long-term studies did develop OA. However, when scientists looked closely, it turned out that running was not a risk factor. Instead, obesity, family history, advanced age and previous muscle or joint injury proved to be the real predictors of future osteoarthritis.

In fact, it turns out that people who exercise -- and this includes short- and long-distance runners -- get extra protection against OA. As we mentioned earlier, runners' muscles are more toned and therefore reduce the pressure the joints are asked to bear. Add in the fact that runners tend to have a lower BMI -- that's body mass index, a measure of fitness calculated by height and weight -- and researchers agree that running is good for you.

Before you race out the door, though, there are caveats. If you have injured yourself in the past, whether a muscle, cartilage or ligament, you may indeed be at risk of further damage. But if you're a healthy individual without a history of injury, running is a good way to boost your weight loss -- and, as you also noticed, your mood.

A few things to consider as you add regular running to your routine:

• If you're over 40 years old or more than 20 pounds overweight, it's probably wise to talk to your primary care physician about your plan to run regularly.
• Proper training takes time, probably longer than you imagine. Don't think in terms of miles at the beginning. Instead, pick a time interval -- 10 or 20 minutes to start -- and mix running with walking as you ease into your new routine.
• Get good shoes and insoles. It makes all the difference to the alignment of your leg, which helps protect your knees. And be sure to replace your running shoes before they wear out.
• Never run when injured. Ever. Sharp pains, sudden pains or pains that are on one side of the body but not the other can be warning signals.
• Yes, you really do need that day (or two) of rest per week to stay injury-free.

Eve Glazier, MD, MBA, and Elizabeth Ko, MD, are internists and assistant professors of medicine at UCLA Health.

Ask the Doctors is a syndicated column first published by UExpress syndicate.

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