By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - Are you an endurance athlete, or on the path to running that first marathon, or participating as a triathlete? Or are you a person who runs that daily 5k? At first glance, you are to be commended because you are clearly doing all you can to stay in condition and keeping your heart healthy, but there is a down side.

You know the phrase, “everything in moderation?” Well, that phrase is very true. Endurance athletes are definitely going beyond moderation and there are concerns.

For instance, you are more likely to have overuse injuries; things like tendinitis, patellofemoral pain syndrome, plantar fasciitis, and stress fractures. You get the idea. A lot of wear and tear. Many of these conditions can be treated by rest. Necessary rehab can help as well, but you need to make sure you go over it with your physician. It’s essential.