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The excessive endurance exercise hypothesis
PETE GLADDEN
Pete’s World
Published: November 20, 2017
If I were to tell you I’d just read an article which concluded that white men who exercise at high levels are 86 percent more likely to experience a buildup of plaque in their coronary arteries by middle age than an identical population group who exercise at low levels, well, you’d probably think I’m pulling a fast one on you.
I’m not.
According to a study done by the University of Illinois at Chicago and Kaiser Permanente, and reviewed in ScienceDaily, 16 October 2017, entitled "Physically active white men at high risk for plaque buildup in arteries,” the combination of high levels of exercise over time may cause stress on the arteries which can lead to increased coronary artery calcification - i.e. coronary artery disease.
To be more specific, this population group is made up of middle age white males who participate in aerobic activities like running, cycling, cross-country skiing, etc., and have participated in these activities at a higher intensity/higher volume than is considered adequate.
And as a matter of fact this isn’t the only study that’s leaning towards the aforementioned supposition. Actually, the idea has had legs for several years now.
Check these out: the March/April 2014 issue of Missouri Medicine, “Increased Coronary Artery Plaque Volume Among Male Marathon Runners”; the BCMJ, Vol. 58, No. 4, May 2016, page(s) 203-209, “The impact of excessive endurance exercise on the heart”; The American College of Cardiology, July 28, 2017, “Lifelong Exercise Volume and Atherosclerosis in Athletes”; and the Mayo Clinic Proceedings, November 2017, Volume 92, Issue 11, Pages 1660–1670, “25-Year Physical Activity Trajectories and Development of Subclinical Coronary Artery Disease as Measured by Coronary Artery Calcium: The Coronary Artery Risk Development in Young Adults (CARDIA) Study”.
And I could continue citing additional studies, but I think you get the drift.
The scary thing here is that the majority of these studies have looked at guys whose BMI, hypertension state, lipid profile, resting heart rate and HDL levels were all very good, great actually. Yeah, we’re talking about apparently healthy, very fit men, guys who exude fitness.
So these apparently healthy men make up a group of both athletes and serious aerobic exercise enthusiasts who happened to participate in their activity at three-times above the national guidelines (more than 450 minutes a week) throughout a period of years. For those of you who don’t care for math, that 450 number equates to seven-and-a-half hours of aerobic activity per week.
Some whacko’s out there, myself included, could easily call a sub-eight-hour week pretty low, more or less a “recovery” week in the grand scheme of one’s training and racing season.
Anyway, in a nutshell these studies postulate that the combination of intensity, duration, and frequency of the activity over time, may cause stress on the arteries, which in turn leads to excessive levels of coronary artery calcification later in life.
What’s more, some of these researchers are reporting that maximum cardiovascular benefits are obtained when exercise/training is performed at moderate doses of both intensity and volume, and that those maximal cardiovascular benefits are lost with high intensity/high volume strategies. In essence they’re saying that too much exercise can be unhealthy.
Now before you fanatical, middle-age marathoner and cyclist guys start sweating profusely about these findings, also know that research further indicates that our genetics may also play a critical role in determining the “exercise safety threshold” of an individual.
That means men who have a family history of cardiovascular disease, strokes, heart arrhythmias, etc., could be much more predisposed to this coronary artery calcification malady as well as other heart-related abnormalities - AGAIN, if engaged in high intensity/high volume aerobic activities across many years.
And it just so happens that I know a little bit about this issue…because I’m one of those white guys who in his late 50’s, was diagnosed with severe coronary artery blockage - despite appearing to be in peak cardiovascular condition.
That’s right. At the age of 59 I came face to face with the “Excessive Endurance Exercise” hypothesis.
But I’m going to leave you hanging here. Next week I’ll talk more about the hypothesis, and how likely it is that this malady played a big role in my current cardiovascular situation.