I enjoyed reading a recent article in VeloNews by Chris Case, entitled “Cycling to Extremes: Are endurance athletes hurting their hearts by repeatedly pushing beyond what is normal?” The article is good reading.
First, I give a lot of credit to Chris Case and the editors at VeloNews. It’s great that a publication with such a broad audience would devote time and space to the issue of heart health and endurance sport. In recent months, they’ve also brought attention to the heart problems of pro cyclists, Robert Gesink, Olivier Kaisen, and Eddy Merckx. I wish that other writers and publications would do the same.
I also thank Lennard Zinn and Mike Endicott for sharing their personal stories with their heart problems. It would be very easy to keep quiet. I very much enjoy reading personal accounts such as these. Their stories are real and also familiar. This is how we learn.
Since the article was published, I’ve gotten a bunch of inquiries asking my opinion about the article in general or about specific information that was presented. Let me share a few thoughts that may be helpful to readers here at the blog….
Don’t be scared (too much)! For most people, cycling is a healthy pursuit. In general, exercise is healthy and provides a myriad of benefits. So don’t stop cycling! It’s important to keep in mind that the stories of Zinn and Endicott are not the norm, even among veteran endurance athletes. Zinn’s multifocal atrial tachycardia (MAT) is one of the least common atrial arrhythmias and Endicott’s sudden cardiac death is rare. As you absorb their stories, focus not on the particular arrhythmias but rather on the possibility that an arrhythmia–any arrhythmia–can cause significant problems or be an indication that things are amiss with the heart. In that sense, their stories should cause you to put on your thinking cap.
My favorite quote from the article? “But fit for racing doesn’t necessarily equal healthy.” Readers here at the blog will know that I’ve said this repeatedly. It’s easy for seemingly healthy endurance athletes, particularly men, to believe that fitness is the same thing as healthiness. This isn’t necessarily true. To dispel the myth, I’ve shared the stories of many elite endurance athletes who’ve struggled with heart problems of various sorts. We can add Zinn and Endicott to these lists. Heart problems are common….and athletes aren’t exempt. This is the most important take-home message from the article.
Arrhythmias are common–in athletes and non-athletes, alike. All athletes experience arrhythmias. Infrequent premature beats, originating in either the atrium (premature atrial contractions, or PAC’s) or in the ventricles (premature ventricular contractions, or PVC’s) most likely have no consequence. Sustained arrhythmias, on the other hand, deserve attention and evaluation. There are far too many varieties of arrhythmias to consider here, other than to mention some of their names: SVT, or supraventricular tachycardia; WPW, or Wolff-Parkinson-White syndrome; atrioventricular (AV) nodal re-entry tachycardia; atrial or ventricular bigeminy; sick sinus syndrome; sinus bradycardia; atrial fibrillation (AF); atrial tachycardia; MAT; ventricular tachycardia (VT); and ventricular fibrillation (VF).
The last part of the VeloNews article alludes to AF. Other than sinus bradycardia (simply a heart rate slower than 60 beats per minute, which may be very healthy in athletes) or innocuous premature beats, AF is probably the most common arrhythmia in athletes. We know from longitudinal studies that the lifetime risk of having AF is approximately 25% in the general population. The question of whether athletes–and endurance athletes, specifically–are more prone to AF is a current controversy, with important implications for long-term endurance athletes. I’ll try to finish up a separate blog post that summarizes the accumulated evidence on this issue. For men, there may be an association with long-term exercise and the prevalence of AF, but there is certainly no consensus among experts. For women, the evidence does not suggest an association between long-term exercise and AF.
Pay attention to warning signs. I particularly like the last section of the article, written by Dr. John Mandrola. He’s a cardiologist who specializes in arrhythmias and who is also a (former?) triathlete and current avid cyclist. He provides good advice in the Q&A. I like to talk about 5 important warning signs of possible heart disease: chest pain or discomfort, especially during exercise; unexplained shortness of breath; light-headedness or blacking out (syncope), especially during exercise; unexplained fatigue; and palpitations–the sense of a rapid or irregular heartbeat. Any of these warning signs may be due to an arrhythmia. All deserve investigation. Dr. John makes the apt point that, very often, heart rhythm problems start off small and get worse with time. Not surprisingly, it’s best to get things sorted out earlier rather than later.
Less may be more. Lastly, I would encourage athletes with identified arrhythmias to be open to the idea that less exercise may be helpful. In fact, this may be the most appropriate prescription. For the long-term endurance athlete, this can be difficult to accept. In this regard, the stories of Zinn and Endicott are particularly poignant.
1. Physical Activity Levels and Atrial Fibrillation
2. Atrial Fibrillation in Athletes (in a Nutshell)
3. Too Much Exercise, Revisited