So far, it looks like the research I’m about to discuss has gone unnoticed by the mainstream media, but I have little doubt that when they discover it, the headlines will be something like “New Research Proves That Exercise Will Kill You!”

The short version of the story is that a recent study found that those who have engaged in endurance exercise for most of their lives have more cardiovascular plaque than those who started such exercise after the age of 30, and considerably more than those who have never engaged in endurance exercise. The “whole-lifers” also had more of what’s considered the worst type of plaque (mixed calcified and non-calcified). Furthermore, the longer the duration of exercise also increased the severity of plaquing.

Now, before you resolve to give up exercise (or never start, as the case may be), there are some important distinctions to be made.

First, this is only applicable to endurance exercise, such as running marathons. Resistance training and other types of exercise have not shown this issue.

Duration of endurance exercise was primarily an issue at a level of 10 or more hours per week – and again, most severe in those who have been engaging in this rather intense exercise regimen for many years.

Finally, although the finding of increased arterial plaque is generally a risk for heart attacks and other serious cardiovascular events, no studies have been done to determine if there is increased mortality in long-term high-duration endurance exercisers. There may be mitigating factors that prevent the plaque from being as problematic as it might be. For example, exercise is known to stimulate angiogenesis (blood vessel formation), and having more blood vessels may compensate for the plaque narrowing them.

In comparison to duration, those with higher exercise intensity showed less plaque development. So a shift in training to shorter, more intense sessions might be a good precaution for those in the highest duration levels.

But again, this is primarily an issue of unusually long durations of exercise over a period of many years.

That said, why would that be a problem?

My theory has to do with inflammation. Inflammation is a known risk factor for cardiovascular disease. It creates points of damage on the inner walls of blood vessels where plaques can adhere and begin to grow.

Any exercise has the potential to produce some inflammation, but the inflammatory response in someone running 10 hours a week, every week for many years never really stops. It might or might not be to the point of causing symptoms like joint pain, but there would be the steady irritation and damage to the blood vessel walls that continuously occurs – as compared to someone who is exercising less and having more recovery time for inflammation to subside and any damage to be repaired by normal cell turnover.

So the findings of this new study, while they fly in the face of the general concept that exercise is good for you, really aren’t too surprising to me.

Exercise, of pretty much all types, is good for you, but there is such a thing as too much. Although the study in question only looked at endurance exercise, overdoing it with any form of exercise can have adverse effects, particularly over a long period of time.

If you have a desire to run a marathon now and then and do the training involved with that, I don’t think this study should deter you. But if you are one of the unusual individuals who has been training 10 or more hours per week continuously for years, it might be worth considering changing your approach just in case.

Until next time…

George F. Best, D.C.