Rock Doc: Excessive aerobic exercise can take a toll on heart

Medical science increasingly has some evidence of a principle your mother warned you about: There really is too much of a good thing.

A few folks throw themselves headlong into aerobic exercise. Most of these hard-core endurance athletes start young. Many fall by the wayside in middle age, but there are also those who keep going, completing marathons and similar events well into retirement age.

What happens to the heart muscles of such titans of lifelong exercise?

A recent British study set out to address that question. It studied men ranging in age from 26 to 67 who were chronic and life-long exercise kings. These guys were fantastically fit. But what could be said about the hearts of the older men in the group compared to the younger athletes and also compared to healthy older men who didn’t do crazy things like run marathons?

Researchers used a new type of MRI exam on the three groups of men, the young and old athletes and the “control group” made up of the healthy older men who had never exercised strenuously day after day. The sophisticated MRI was capable of showing truly early stages of scarring (fibrosis) of the heart muscle.

Interestingly, none of the younger athletes had early fibrosis in their hearts – but neither did the older men who didn’t follow enormously demanding exercise regimes. (The older men had been screened to be healthy subjects.)

But what was striking were the results from the older male athletes. Half of them had hearts that showed some muscle scarring. And the men with the fibrosis were those who had exercised the hardest and the longest.

To repeat, the information from Britain doesn’t get us off the hook when it comes to exercise. Let’s face it, most of us Americans are generally in no danger of running marathons. In general, aerobic exercise is good for the ol’ heart and lungs, and will help you ward off such maladies as Type II diabetes. And if you’ve noticed lately that you’re getting just a bit older, exercise is your best single bet to help combat the battle of the bulge.

But it’s also true that completing oodles of marathons may be a bit excessive.

Here’s one final thought: inquiring minds might well ask why women were left out of the investigations. For years it’s been commonplace to leave us females out of many research populations. The logic has been that women are different from men. (Yes, doctors have noticed that – medical school is good for something.) In order to have a simple study with only a few people in it, so the reasoning goes, it’s best to eliminate women from the research because their bodies might have differences that would affect the outcomes of the work.

Mind you, we could reverse that logic. Researchers interested in heart health, diabetes, or colon cancer could study only women – because after all including men in such studies could complicate results. Then we could just assume what’s true for women simply must be true for men.

That’ll be the day.