In recent weeks, I’ve talked about some of the potentially adverse effects of long-term participation in endurance sports. I’ve drawn your attention to a couple recent studies that have shown that: 1) endurance athletes are more apt to develop atrial arrhythmias, sometimes long after their participation in sports has ended; and 2) marathon runners may have more plaque build-up in their coronary arteries over time than their non-runner counterparts. Each of these issues deserves further study.
On the brighter side, today’s edition of the Journal of the American College of Cardiology features a report by a group of investigators in Rome, Italy, headed by Antonio Pelliccia, MD, entitled “Long-Term Clinical Consequences of Intense, Uninterrupted Endurane Training in Olympic Athletes.” I’d like to draw your attention to both this article and an accompanying editorial by Drs. Paul Bhella and Benjamin Levine because they offer some good news about long-term heart health in endurance athletes.
The current study was motivated by several observations. As Drs. Bhella and Levine note, the primary cardiovascular adaptation in elite endurance athletes is a very large stroke volume (the amount of blood the heart ejects with each beat), “achieved by a compliant heart that relaxes quickly.” But is there any harm that comes with these adaptations? We do know that there is a consequence known as “cardiac fatigue,” a temporary reduction in heart pumping function following endurance events such as Ironman distance triathlon. We also know that there is release of cardiac enzymes (suggesting heart damage) into the bloodstream after marathon running events. What’s not known is whether there is damage to the heart over the long term.
The current study involves 114 Italian athletes from a variety of endurance disciplines (55 rowers, 19 cyclists, 8 middle-distance runners, 9 long-distance runners, 15 cross country skiers, 6 swimmers, and 2 triathletes) who participated in at least 2 consecutive Olympic games. These athletes had participated in their sports for anywhere from 1 to 15 years before selection to their first Olympic team and continued to participate in their sports for 4 to 17 years after selection to their first Olympic team. This group of athletes participated in a total of 344 Olympic games and 42 (37%) were medalists at least once.
The athletes were tested before their first Olympic games (baseline evaluation) and again (final evaluation) at their final Olympic games (or World Championships). The average time between the 2 evaluations was 8.6 +/- 3.7 years. Their cardiac evaluation at these 2 timepoints included:
1. physical examination
2. measurement of the blood pressure
3. exercise EKG
4. echocardiogram (ultrasound test of the heart).
Over the period of observation, the authors reported that there were NO cardiac events or new diagnoses of cardiomyopathy (weakening of the heart muscle). In addition, the echocardiograms showed that there were no abnormalities in the pumping function of the heart and that the dimensions of the cardiac chambers were unchanged except for a small increase in the size of the left atrium.
This news should be encouraging to the many endurance athletes out there. It’s really the first study to document preserved heart function after years of intense training and competition among endurance athletes. I suppose it’s important to recognize that the study population here is VERY select. Indeed, there are relatively few athletes who fit into the category of repeat Olympians. But the results are probably meaningful to the many millions of us who engage in some form of endurance sport. And this time, it’s good news.