Common wisdom says that running is good exercise. It relieves stress, helps control weight and promotes cardiovascular health. But, now, a 2012 study published in the prestigious Mayo Clinic Proceedings suggests that too much running may be bad for your health and could, in fact, kill you.
So, how much running is too much? The study’s author pointed out that people should not stop moderate running. His work involved extreme runners—people who train repeatedly for 52.4-mile double marathons or 100-mile ultramarathons. How was their health aff ected? It was not through running injuries, although shin splints, runner’s knee, and other leg and joint problems are common in extreme runners.
The study found that extreme running over an extended period caused thickening and scarring of the heart walls, heart enlargement and other changes that made the runner more susceptible to heart arrhythmias. Another study found that 12% of apparently healthy marathon runners had heart scarring. Still another discovered that people who ran more than 25 miles per week or who ran at a pace faster than 10 minutes per mile were more likely to die than were people who ran up to 20 miles per week at a slower pace.
How is it that running can both benefi t and damage the heart? Researchers believe that the cardiovascular benefi t curve for runners is ∩ shaped. Moderate running increases health. But, at some point, the runner reaches the top of the curve, and the benefi ts max out. Beyond that point, too much running has the potential to damage the cardiovascular system. Where the “too much point” lies is under debate, and more research needs to be done.
We can help you avoid overuse injuries and exercise burnout by designing a balanced cross-training program that incorporates cardiovascular fitness, along with strength training, flexibility and balance exercises. We will review your current exercise program or devise a balanced program appropriate to your particular fitness level.
