490BC – Pheidippides, a messenger by trade, runs 25 miles from Marathon to Athens to deliver news of a Greek victory.  After delivering the message, he collapses and dies at the age of 40.

7/20/84 – Jim Fixx, author of “The Complete Book of Running”, drops dead of a heart attack at the age of 52.  Dr. Eleanor N. McQuillen, Vermont’s chief medical examiner who performed an autopsy on Mr. Fixx, said in an interview that all three of his coronary arteries were damaged by arteriosclerosis, the underlying cause of heart attacks.

3/19/04 – Brian Leigh Maxwell, an avid marathoner and founder of PowerBar dies of a heart attack at 51 years old. 

12/19/04 – Greg Marr, Editor of Silent Sports magazine and an avid runner, dies unexpectedly while skiing at Iola Winter Sports Center in Iola, Wisconsin. While skiing, Marr collapsed as the result of a heart attack. He was only 52 years old and in excellent physical condition.

Those are just a few of the many examples and those don’t include individuals who had heart attacks but did not die.  All of the aforementioned cases were of individuals in peak physical condition, with no genetic abnormality (e.g. enlarged heart) and were avid distance runners and marathoners.  None of these cases involved an out of shape individual who ran all out on a whim and suffered a heart attack.  How do seemingly “fit” individuals drop dead at a relatively young age?  The activity they thought was increasing their life span ultimately cut it short. 

Long Distance running can induce arrhythmia
 An arrhythmia is also known as an irregular heartbeat.  When a heart beats irregularly, it can either beat too slow (bradyarrhythmia – less than 50 beats per minute) or too fast (tachyarrhythmia – faster than 100 beats per minute).⁽¹⁾  “Athletes with no discernible danger can be susceptible to arrhythmias, especially during runs of 15 miles or more. On long runs you can become significantly dehydrated, leading to changes in the blood’s levels of potassium, magnesium, and calcium.  These chemicals play a vital role in starting and conducting electrical impulses in the heart.”⁽²⁾ An arrhythmia can lead to cardiac arrest and ultimately death.  Notice the key statement above (15 miles or more), we aren’t talking about a jog around the block.

Long distance running INCREASES coronary plaque buildup
Based on the multitude of treadmills at the average gym, the idea of jogging endlessly gives the impression that you are “getting in some cardio” and that “your heart will thank you”.  Two recent studies show that is NOT the case.  One study, administered at the West-German Heart Center Essen, focused on male marathoners age 50 and up.  Among the study’s findings, while the runners had lower than average cholesterol levels and better blood pressure, they had more measurable coronary calcium buildup or plaque than the general population.  In the study, German scientists scanned the hearts of 108 experienced, male distance runners in their 50s, 60s and 70s.  The runners had completed a minimum of 5 marathons in the previous 3 years.  When the researchers studied the runners’ scan results, they found that more than a third of the men showed evidence of significant calcification or plaque build-up in their heart arteries.  Several also had scarring of some of the tissue in their hearts.  The researchers stated, “In our study regular marathon running seems not to protect runners (from coronary artery disease).  In fact, we even cannot exclude the possibility that exercise to this degree has deleterious effects on coronary arteries.”⁽³⁾

A second study of 25 middle-aged male runners, each of whom had completed the Twin Cities Marathon annually for the past 25 consecutive years, demonstrated they had significantly greater mean volumes of coronary calcified plaque than did age-matched sedentary controls.  The lead researcher, Dr. Jonathan Schwartz said, “The bottom line here is just because you run a lot of marathons and you’re very active doesn’t mean you’re protected from coronary artery calcification.  Benefits to long-term, high-volume endurance training for overall health include favorable body mass index, heart rate, and lipid panel, but these may be counterbalanced by metabolic and mechanical factors that enhance coronary plaque growth.”⁽⁴⁾  Coronary plaque reduces blood flow which can result in a heart attack and if a piece breaks off, one may suffer a stroke.  Heart attacks and strokes usually result in various forms of irreparable damage and often result in death.

Long distance running increases the buildup of scar tissue in and around the heart
A recent study published in the Journal of Applied Physiology⁽⁵⁾ examined the incidence of myocardial fibrosis (scar tissue in and around the heart) in veteran lifelong endurance athletes.  The study involved 12 veteran athletes ages 50-67, 20 age-matched controls (non-athletes) ages 52-69 and 17 younger endurance athletes ages 26-40.  50% of the veteran endurance athletes had scar tissue in and around their heart versus ZERO in the younger athletes and the non-athletes who were the same age.  As stated in the study, “The affected men were, in each case, those who’d trained the longest and hardest.  Spending more years exercising strenuously or completing more marathon or ultramarathon (>50 miles) races was, in this study, associated with a greater likelihood of heart damage.”⁽⁵⁾  Scar tissue is rigid and can cause the heart to beat irregularly and ultimately lead to heart failure.  A recent study in laboratory rats⁽⁶⁾, showed a link between certain kinds of prolonged exercise and heart damage.  For the study, published in the journal Circulation, scientists had young, healthy male rats run at an intense pace, day after day, for three months (10 years in human terms).  The training was designed to mimic many years of serious marathon training in humans.  The rats had begun the study with perfectly normal hearts.  At the end of the 3 months, heart scans showed that most of the rats had developed scarring and some structural changes, similar to the changes seen in the human endurance athletes.  A control group of unexercised rats had developed no such changes to their hearts.

I know what some of you are saying, “I am not running marathons for a living, I just want to do one!” OR “I have ran a marathon a few times, what’s the big deal?”  Did you know that the stress placed on your body after just one marathon can produce inflammation and negative effects that last for up to 3 months!!!  Dr. Eric Larose told the 2010 Canadian Cardiovascular Congress, “…marathon running can damage your heart.  Fortunately the exercise-induced injury is reversible over time, but it could take up to three months to completely recover.”⁽⁷⁾

Marathoner vs Sprinter: which would you rather look like?

The fact of the matter is that our bodies were not meant to run long distances for long periods of time.  At the end of the day, we are animals.  Have you ever watched the Discovery Channel or observed animals before?  If you have then, you would notice that the vast majority of the time they are resting.  Whether it is your dog, your cat or the lion hanging out in the Serengeti in Africa, the vast majority of the time, they are relaxing.  When they do move to catch pray or avoid a predator, they sprint.  This activity does not happen often or for prolonged periods, it is only when necessary.  Their “exercise” involves short intense bursts not long slow movements such as jogging.

You don’t see him jogging for hours on end

The intent of this article is not to justify being lazy or sitting and doing nothing.  Most folks in America don’t have the problem of too much exercise, but rather too little.  What I don’t want to see is you wasting your time doing distance running when you can get better results in less time, all without damaging your heart.  The best part is that you can gain muscle AND burn fat rather than look like a skinny weakling!!!  Tune in next time to find out the cardio that you SHOULD be doing.

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References:

1) Robert J Bryg, MD. “Heart Disease and Abnormal Heart Rhythm (Arrhythmia)”, Published on 3/7/09, Accessed on 3/25/11. http://www.webmd.com/heart-disease/guide/heart-disease-abnormal-heart-rhythm

2) Jennifer Pirtle. “The Heart of a Runner”, Runner’s World magazine. August 2004.

3) Breuckmann F, Möhlenkamp S, Nassenstein K, Lehmann N, Ladd S, Schmermund A, et al. “Myocardial late gadolinium enhancement: prevalence, pattern, and prognostic relevance in marathon runners”, Radiology. April 2009 251:50-57.

4) Schwartz JG, Merkel-Kraus S, Duval S, et al. “Does elite athleticism enhance or inhibit coronary artery plaque formation”. American College of Cardiology 2010 Scientific Sessions; March 16, 2010; Atlanta, GA.

5) Wilson MG, O’Hanlon R, Prasad S, Deighan A, Macmillan P, Oxborough D, et al.  “Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes”, Journal of Applied Physiology. Published online 2/17/11. http://www.ncbi.nlm.nih.gov/pubmed/21330616

6) Begoña Benito, MD; Gemma Gay-Jordi, PhD; Anna Serrano-Mollar, PhD; Eduard Guasch, MD; Yanfen Shi, MD; Jean-Claude Tardif, MD, et al. “Cardiac Arrhythmogenic Remodeling in a Rat Model of Long-Term Intensive Exercise Training”, Circulation. 2011;123:13-22. Published online before print December 20, 2010.

7) Dr. Eric Larose. “Marathons damage the hearts of less fit runners for up to 3 months”, Canadian Cardiovascular Congress 2010; October 25, 2010; Montreal, Quebec.