Intense training for many years causes the heart to grow in many endurance athletes and is termed “athletic bradycardia,” or “athlete’s heart.” Usually the heart only grows when something is wrong, so for years this was considered somewhat dangerous by cardiologists. Today we know that most athletes’ hearts reverse themselves to more normal proportions when cutting back on training, and this condition is not considered dangerous. The only complication is that it can be difficult to establish whether or not a big heart is caused by training or by a possible heart condition, so diagnostics may be more complex when working with athletes.
With the growth of extreme endurance sports such as the marathon, long-course triathlon and ultra-running, more interest has been given to the potential adverse acute effects of long and intense training and racing on the heart. Studies of the heart function in athletes after finishing an Ironman show that some blood markers, such as troponin, a protein involved in muscle contraction, are at increased levels, indicating damage to the heart muscle, similar to what is measured from skeletal muscle after prolonged intense exercise. Also heart function may be slightly reduced and there may be slight leaks at the valves directly following extreme exercise. However all of these factors usually reverse within a 48-hour period. So it seems that the heart recovers after races just as other muscles do.
If one goes through such intense exercise bouts day in and day out, week after week, year after year, however, long-term changes may occur in the heart muscle. In studies done on athletes who have run more than 100 marathons and veteran Ironman athletes, scientists have identified, in 12 to 15 percent of these individuals, scarring in various parts of the heart. Again this is similar to what is seen in the skeletal muscle of long-time marathon runners. However, the consequences may be more severe when it comes to the heart muscle. While there are still many things we do not know when it comes to the effect of extreme exercise on the heart muscle, one pattern is evident: In the scientific literature, at least 12 studies found a four-fold increased risk of developing arrhythmia in athletes who have trained vigorously for 10 or 15 years, compared to people who exercise in more moderate amounts. Most of these arrhythmias are not acutely dangerous as many people live with them and still exercise. But as is the case with my own condition, heart troubles are always complex to deal with, and arrhythmia may bring other adverse effects such as a higher risk of stroke as you age. In addition, some of these cases may be more serious and in very, very rare cases certain arrhythmias may be fatal. Other studies indicate that high-level training may increase calcification and stiffening of the aortic wall in addition to arrhythmia.
Obviously it would be nice if physicians could establish training guidelines for how much is too much, but since each person is unique and we all have a different tolerance for training, that’s not possible — at least not now. One typical patient for sports-related arrhythmias, according to physicians I spoke to who deal with this issue, is a person with a 10- to 15-year career on an elite level plus another 10 years of continued intense training after that. The other pattern doctors have noticed in their studies is that it is the hours done rather than the intensity that affects the development of arrhythmias. Almost any athlete can be affected, though. Life stress and genetic factors, in addition to the training, may count as a trigger as well, even when training is less intense over fewer years.
Dean Harper, one of triathlon’s early greats, put in decades of intense training and this year turned 60. In the early ’80s, while our sport was still in its infancy, before wetsuits and triathlon-specific bikes, Dean raced and trained with the big four: Mark Allen, Dave Scott, Scott Tinley and Scott Molina. He won the U.S. Long-Course Championships and the first edition of the Wildflower triathlon in 1983, and he was on the cover of the first issue of Triathlete in May of 1983. If there were ever a “big five” in triathlon, Dean would likely have been part of this elite group.
While the lifestyle back then was more relaxed than it is today, his training philosophy was rather simple: Train more than Dave Scott. Dean and Dave had competed against each other while swimming and playing water polo in college and sometimes trained together. Since Dave is one of the hardest workers in the sport, doing more meant pushing the limits daily. In those years Dean usually completed 25,000 yards of swimming, 400 miles of biking and 80 to 90 miles of running each week. After winning several other pro races in the shorter distances, Dean retired from pro racing in 1986 to raise a family and practice law. During the following 16 years he still trained about an hour a day. Often it was intensive threshold work, but he did not race.
In 2002 he took up the sport again as an age grouper. While training for Ironmans he would push the training upward of 25 hours a week, which is incredible considering he is a partner in a law firm and has an active family life with three children. In 2008, he won a USA Triathlon National Championship and, later that year, came in third in his age group in Kona. The year after, in 2009, he won an ITU Age Group World Championship in the 55–59 age group. However, in those years, Dean also developed various arrhythmias in his right atrium, most likely due to all the years of intense training.
Dean had his first premature ventricular contraction back in 1986 after a hard swim practice. If you have not had one, it feels like your heart skips a beat and then contracts very forcefully. It scared him, so he went to his physician to get checked out. He was told not to worry, but it began again when he resumed his competitive training some 16 years later. The PVCs became more regular and in 2003 at the age of 50 he experienced his first case of what he now knows is atrial fibrillation, where the atrium beats in a chaotic rhythm. It lasted 24 hours, but he was already used to having PVCs quite often. For the following years while training and racing as an age grouper he would experience an A-fib about twice a year, usually after really hard or long training sessions. He had it once during an interval workout on the track and went from running 6:30 miles to barely being able to hold 10-minute pace as the fibrillation causes the heart to become far less efficient while it is beating. After some years Dean also started to experience atrial flutter, which is a sustained heart rate of 120 to 150 beats where the heart does not pump as much blood as it should.
In 2009, after winning short course worlds, Dean was set on the world champs in Kona. It was on his bucket list to win his age group at the Ironman World Championship. Before the race, though, he developed a viral and fungal infection in his throat and was on medications leading into the race. He still started the race, but immediately felt he was off. He could not bear the thought of not finishing and held on despite the illness in his body. Looking back, Dean says he was probably pushing the envelope too much, as he started to experience more regular bouts of atrial fibrillation and atrial flutter after the race. His doctor recommended that he see a specialist, who suggested ablation surgery, in which some of the cells causing the abnormal heart rhythm are cauterized. The first surgery caused his heart to go into fibrillation without coming back before it was shocked. He got another surgery from one of the leading experts in the field, which was successful in terms of the arrhythmias, but at the same time greatly reduced Dean’s physical capacity. Today, Dean’s resting heart rate is 60, instead of 40, and despite intense training he is unable to perform at the level he once was. He still enjoys doing four-hour rides with his youngest daughter, Shelley, an elite collegiate swimmer now competing as a triathlete, and he still races, but he is no longer able to pursue his original goals. Had he known this before the surgery he says he would have waited and exploited alternative strategies such as meditation to reduce the arrhythmic incidences. This underlines the importance of always finding a doctor who knows about sports and an athlete’s mentality.
While Dean’s story may be extreme, it may be the story of a growing number of triathletes. Both professionals and elite amateurs embrace our sport as an identity in which they train and race under the motto “never quit.” Those two words, along with huge training volumes, are weaved into the “iron culture.” We may think that we as athletes are strong and healthy, but as my story, as well as Greg’s, Emma’s, Normann’s, Dean’s and many others show, some of us and especially those who push the limits to extremes, may only be a heartbeat away from an ambulance and a hospital bed.
Does this mean you will die in your next race? No! Deaths are very, very rare in triathlon and compared to other risks in life, endurance sports are quite safe. A recent study from USA Triathlon investigating swim deaths concluded that from 2006 to 2011 the mortality rate in triathlons was only one in 76,000. In other words, for every 76,000 participants there was a death from cardiac or other reasons. As a point of reference the risk of dying each time you get in your car is around one in 20,000.
Is triathlon dangerous for your heart health? No, triathlon is for the vast majority of us a very, very healthy activity that prevents a multitude of diseases and brings us joy every day. But when the training and the racing are taken to extremes, when the mantra “never quit” forces you to train and race through illness and injury and when your “iron will” makes you disregard the messages you receive from your body on the brink of collapse, you are in the gray zone and face risks above the norm in terms of developing arrhythmia and potentially other heart malfunctions.
Health is an individual thing. In medical terms, health is often reduced to how long you live, not how you live. For all of us, it is important to consider the longevity, quality and meaningfulness of our lives. Endurance sports such as triathlon are to most of us a very meaningful part of life, providing fuel for our identity and experience.
As Dean puts it, “I love to train and stay in great shape. Although my condition limits my ability to compete at the highest level, I will never stop training unless it became life-threatening. It has brought, and continues to bring, great happiness. And I am hoping that medical science will continue to progress so that my type of issue is better understood and dealt with in athletes.”
I can understand why some choose, as I did for many years, to chase the dream. However, life is long and what you see as acceptable risks now may not be acceptable later on. We need to chase our dreams, as our ability to do that makes our lives meaningful, but we also need to balance and control the risks we take in the process. After all, that is what leads to peak performances in sport and in life.