Dr. John Mandrola, a cardiologist (specializing in electrophysiology) in Louisville, KY, who blogs at http://www.drjohnm.blogspot.com, brought an interesting report to my attention the other day.
Included among the abstracts presented at the recent annual meeting of the American College of Cardiology was a report from Dr. Jonathan Schwartz (from the University of Colorado) and his father, Dr. Robert Schwartz (from the Minneapolis Heart Institute). It turns out that father and son investigators are both runners.
These investigators examined a group of 25 runners who had completed the Twin Cities marathon for 25 consecutive years and compared these runners to a control group of non-athletes that were similar in terms of age, restinig blood pressure, renal function, smoking history, height, total and LDL cholesterol, and triglycerides. The runners did have a lower heart rate, weight, and body-mass index and higher HDL cholesterol levels.
All of the subjects underwent coronary CT angiography (CTA). This is a relatively simple x-ray test designed to find build-up of calcium in the coronary arteries (the arteries that supply the heart itself). And recall that when these arteries become blocked with calcium-laden plaque, problems such as angina or heart attack (myocardial infarction) may occur.
The investigators found that there was a significantly higher calcium plaque volume in the runners than in the control group. Sixty percent higher, in fact.
Why could this be? Again, the healthy benefits of exercise have been well-established. But the authors here suggest that these healthy benefits might be “counterbalanced by metabolic and mechanical considerations” and that the calcium plaque build-up may be “a response to high exercise levels across a lifetime.”
There have been precious few studies of the long-term effects of (potentially excessive) exercise on the cardiovascular system, so we really don’t know the cause of these findings. But it could well be the case that, beyond some point, the chronic effects of participation in endurance sports may actually be harmful.
Reports like this make you think.
This doesn’t surprise me. I’ve always felt that what we do is far beyond what our bodies were designed to do.
Jennifer Spitzer says
I’m not a doctor, but it seems to me that the results of this study are only good enough to conclude that additional study is necessary. If you look at the total number of marathoners and triathletes nationwide, this study doesn’t provide anything that can be considered statistically valid.
Lawrence L. Creswell, M.D. says
I’m not surprised either. It’s probably like many things in life….moderation is best. For many endurance athletes who enjoy competing, there is “training” that is far in excess of just “exercise.” And I think that investigators are just now beginning to look at the long-term effects.
Lawrence L. Creswell, M.D. says
Thanks for your comment.
Yes, this is a VERY small study. And so there’s no guarantee that the small number of subjects are actually representative of runners (or other endurance athletes) as a whole.
But this is an interesting observation. A new observation. An observation that deserves further study.
There is an ever-larger population in this country that participates in endurance athletics at some level, so it will be worthwhile to learn about the long-term health effects….not only on the cardiovascular system, but for the body’s other systems as well.
I suspect that this study will prompt a variety of new studies in this regard.
I’d have to look into this further, so this is only a theory, but it could be related to acidity. When the blood is too acidic, calcium is used (taken from the bones) as a buffer. Too much serum calcium can lead to arterial plaque. Acidity may be the result of these two factors: 1) Exercise alters the pH of the system, athletes are exercising at a high level; 2) Athletes tend to opt for an acidic diet – their choice of energy comes from grain/flour carbohydrates bread, pasta, rice etc) all of which are acidic. Something to consider… There is now plenty of research that supports the use of vegetables/fruits as sources of carbohydrates over grains for athletes – both are nutrient dense and alkaline… see The Paleo Diet for Athletes by Lauren Cordain and Joe Friel for example.
Just wondering if anyone is aware of any further studies done on this. I am a lifetime runner in my early fifties and I have been doing two marathons a year. I enjoy to compete and to train, however after stumbling upon this website I am now wondering if I am doing my heart more harm than good. As far as I know I do not have any heart issues but would like to know if I should talk to my Doctor about having some tests done and if so what should I request be done… so that at least I will feel better about going out for my lunch time run every day.
Any suggestions are much appreciated.
i’ve heard of this in an editorial from Dr O’Keefe but i’ve search on pubmed if these datas were published, i didn’t find them anywhere 🙁
do you know if it was published ?
Larry Creswell, MD says
A couple references:
1. Mohlenkamp S et al. Running: The risk of coronary events. Eur Heart J 2008;2008:1903-1910.
2. Schwartz RS et al. Increased coronary artery plaque volume among male marathon runners. Missouri Medicine 2014;111:85-90.