An “Iron” response…

The most famous medical blogger once direct-messaged me this advice:

“One thing I have learned from blogging is to never engage criticism.”

I’m going to break this advice.

The robustness of the response over the Ironman piece shocked me. As a bike racer, a cardiologist, and a happily married man, I have grown thick skin. Being called an atrocity really didn’t hurt me. What did strike me as reasonable criticism, however, was the lack of references. This I can remedy.

But first let me make three introductory points.

–Blog versus a scientific article: Let’s make sure that one understands the distinction between a blog post and a scientifically-vetted scholarly article. See disclaimer #3 in my “about the blog” tab:

Please do not confuse a blog post with a scientific paper or multi-referenced review article. I don’t have an army of foundation-supported researchers. It’s just me trying to help.

My words come free; that fact should speak volumes. In the blog-o-sphere, you, the reader, are the person doing the vetting.

–I am not a journalist–though perhaps a star-struck wanna-be.

–As a heart rhythm specialist, I see an atypical cardiac population. While my “plumbing” colleagues see America, as you see it in the mall, the state fair or sadly now, in our schools, I see you over-achievers: engineers, CEOs, doctors, lawyers, and of course, the endurance athletes. You sit on my table wide-eyed, staring forward in disbelief that a heart rhythm problem could occur in your sculpted bodies and minds. You have done everything right: gone to bed on time (mostly), ate good food, studied for tests and followed the training plan. How could you have atrial fibrillation?

This paradoxical observation: that certain arrhythmias–AF in particular– strike at the over-achieving, is something that interests me enough to write about. Perhaps, it’s because I am like you. I want to be the best heart rhythm specialist possible; I want to defy my genes and pedal more watts, for longer; I want to learn as many words as a WSJ writer; or come up with a fictional story that someone would find interesting. So I get your focus and drive.

But…I have also trained at the Academy. The distinguished center known for teaching this central tenet: as outlined in the comments by its director, RDB:

“In the pursuit of better, people often screw up good.”

Enough with the speech and disclaimers; here’s some real data:

Here is the seminal article on cardiac fatigue during the Ironman.

It was an ultrasound study of Hawaii Ironman finishers. The news is not good: measures of heart function looked terrible after the race. Though these changes reversed in recovery; this blogger’s opinion holds that things that damage your heart are not good. “Are you feeling lucky?”

On the association of atrial fibrillation and endurance exercise:

There are hundreds of citations documenting the risk of atrial fibrillation in long-term endurance athletes. You can start by feasting on these nuggets…

• Karjalainen J, Kujala UM, Kaprio J, Sarna S, Viitasalo M. Lone atrial fibrillation in vigorously exercising middle aged men: case-control study. BMJ. 1998; 316: 1784–1785.
• Furlanello F, Bertoldi A, Dallago M, Galassi A, Fernando F, Biffi A, Mazzone P, Pappone C, Chierchia S. Atrial fibrillation in elite athletes. J Cardiovasc Electrophysiol. 1998; 9: S63–S68.
• Mont L, Sambola A, Brugada J, Vacca M, Marrugat J, Elosua R, Pare C, Azqueta M, Sanz G. Long-lasting sport practice and lone atrial fibrillation. Eur Heart J. 2002; 23: 477–482.
• Hoogsteen J, Schep G, Van Hemel NM, Van Der Wall EE. Paroxysmal atrial fibrillation in male endurance athletes: a 9-year follow up. Europace. 2004; 6: 222–228.
• Heidbuchel H, Anne W, Willems R, Adriaenssens B, Van de Werf F, Ector H. Endurance sports is a risk factor for atrial fibrillation after ablation for atrial flutter. Int J Cardiol. 2006; 107: 67–72.
• Elosua R, Arquer A, Mont L, Sambola A, Molina L, Garcia-Moran E, Brugada J, Marrugat J. Sport practice and the risk of lone atrial fibrillation: a case-control study. Int J Cardiol. 2006; 108: 332–337.

Though the exact mechanisms, individual susceptibility and best treatment course for athletes with AF are not completely understood, it is completely un-credible to deny the association of AF and long-term exercise.

Coronary Calcium and long-distance running.

Here, the data are emerging. I offer you this theHeart.org piece from last year.

Cardiac Fibrosis and endurance exercise:

Here, I refer you first to Gretchen Reynolds, the famous NYTimes exercise writer. Her column is where I first learned the story of the marathon rat. I know, humans aren’t rodents, but the data from the highly respected lab of Stanley Nattel (Canada) are sobering. Yes, you can guess the results: rats that were run excessively (if given the chance, most rats will indeed run too much) developed areas of scarring in the heart.

And this very troubling finding doesn’t just happen in rats. Here are two studies that suggest the possibility of this irreversible phenomenon happening in humans: (there’s many more)

• Whyte G, Sheppard M, George K, et al. Post-mortem evidence of idiopathic left ventricular hypertrophy and idiopathic interstitial myocardial fibrosis: is exercise the cause? Br J Sports Med 2008;42:304-305.
• Cocker MS, Strohn O, Smith DJ, et al. Increased incidence of myocardial fibrosis with reduced cardiac function in elite high-endurance athletes: a cardiovascular magnetic resonance (CMR) study (abstr) Circulation 2008;118S840–b.

In conclusion…

There is ample data to generate the hypothesis that exercise has an upper-limit. My humble opinion, honed through a 15-year heart-rhythm experience, and a keen eye for the obvious suggests to me that long-term, low-intensity, ultra-endurance exercise (slogging, not racing) isn’t heart-healthy.

As sir Charles says, “I may be wrong…but I doubt it.”

JMM

P.S. Although this sounds a tad like self-promotion, readers can read my (archived) thoughts on exercise, inflammation and healthy living by clicking the categories tab on the right column of the blog. You will find many referenced articles in these posts.