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Shedding Light on Cardiac Disease in Endurance Athletes

What do runners Alberto Salzar, Ryan Shay and Michah True have in common? What about triathletes Emma Carney and Greg Welch? Or cyclist Lennard Zinn? They are all well-known, highly respected endurance athletes AND they all have either died from or been diagnosed with cardiac issues.

Despite these high-profile athletes joining the ranks of those with cardiac disease, many athletes still believe it could never happen to them. I was one of those athletes. A few years ago, I was training for Augusta 70.3, and I had many of the signs and symptoms outlined below and brushed them off. Ultimately, I discovered I had a rare genetic heart disease called ARVC and can no longer train or compete. I nearly died and now consider myself very lucky to be here. This month in Atlanta, the Atlanta Track Club held a symposium on cardiac health in runners. I am glad the topic is becoming more and more discussed in the media and in our subculture of endurance athletes. I hope this blog post and my knowledge of this topic can keep this conversation moving. 

It is both surprising and upsetting when we see headlines such as:

“Thirty-year-old marathoner dies at mile 22.”

”Cyclist leaves tour because of heart issues.”

“Ironman athlete dies during swim start.”

Sudden death in endurance athletes occurs in a small percentage of people, often in those less than 35 years of age [1]. Sudden death can be a result of dangerous arrhythmias, congenital defects or coronary artery disease.

The popularity of endurance sports, such as running, triathlon and cycling, has been increasing year over year. The number of U.S. race finishers has increased nearly 300% since 1990 [2].This means that many people entering the world of endurance sports are people with a family history of heart disease, former smokers, those who have a history of high blood pressure or people with unhealthy lifestylestrying to change their lives. One of the many things I love about endurance sports is that they give people an avenue to take their lives back and improve their health, even if they weren’t always healthy.  

On the other side of the spectrum, just because someone is young or healthy and always has been doesn’t mean that person is not at risk. This is why it is important to be aware of possible cardiac issues in athletes and to be able to recognize signs and symptoms of cardiac disease.

Let's first start with some basics.  

The Heart:

The heart is responsible for pumping blood and oxygen to your brain, your muscles and all of your vital organs. On average the heart beats 100,000 times a day[3], and that is without exercise! The heart takes deoxygenated blood from your body and runs it through the lungs to make it oxygenated again, and then pumps it back through your body. The heart has four chambers: two atria, which make up the top chambers of the heart, and two ventricles, which are the lower chambers. There are four valves that help to regulate blood flow in the heart.

The heart has its own conduction system, which regulates the heartbeat. The SA node at the top of the heart sends a signal telling the chambers when and how to contract in order to pump blood through the system. When all is functioning well, the chambers contract flawlessly in a coordinated manner, and we are none the wiser. 

It is when something in the system goes awry that we begin to notice issues. 

What are possibly dangerous signs and symptoms to be aware of?

Family history, especially a history of family members dying young*

Heart racing or skipping beats

Lightheaded or dizziness

Syncope (or passing out)

Unexplained increased fatigue

Chest tightness

Difficulty catching your breath/shortness of breath

Fluttering in your chest

Difficulty with normal training load

Decreased performance

Inconsistencies or extreme jumps in your heart rate during training

Pain in the chest, neck or arm with exercise

If you have experienced any of these symptoms, then it would be wise to be checked out rather than to ignore them. 

3 Possible heart issues in athletes:

  • Arrhythmias: Arrhythmias involve the conduction system of the heart. They can cause the heart to beat too fast, too slowly or erratically. They can occur in the atria or the ventricles. When the rhythm of the pumping is affected, then blood flow to the brain, vital organs and muscles can be impeded. Arrhythmia may or may not be life threatening. Click here to see a video of what your heart does during various arrhythmias [5]. 

  • Cardiomyopathy: Cardiomyopathy is a disease of the heart muscle. The heart muscle may have scarring, becoming enlarged, thick or rigid. Hypertrophic cardiomyopathy (HCM) and arrythmagenic right ventricular cardiomyothapy (ARVC) are two cardiomyopathies seen in athletes. HCM is a more common cause of sudden death in athletes (36%) vs ARVC (4%) [2]. 

  • Coronary Artery Disease (CAD):This is typically seen in older athletes and less often results in sudden death. It occurs when there is plaque buildup in the arteries that blocks blood flow. Despite the common belief that if you eat well and exercise you will not have CAD, that is not always the case. Even if you are healthy and take care of yourself, you may still be at risk. 

There are many other things that can go wrong with the cardiovascular system, but I am not a cardiologist, and you don't want me to list them all! If you have concerns or questions, it is best to ask a cardiologist directly.

What can you do?

We can all keep the conversation about heart health in endurance athletes going. We need to continue to be aware of signs and symptoms and to talk with our training partners, our clubs and our health care practitioners. The more people are exposed to this topic the more likely they will be able to catch issues before something terrible happens.

If you notice your training partner is not himself or herself, say something.

You can also go to a sports cardiologist and get screened. If you are new to endurance sports, have a family history of heart disease or just want peace of mind, it doesn’t hurt to be screened. 

Why is it important to see a cardiologist that understands the difference between athletes and non-athletes?

Athletes are different. An athletic heart looks different than a non-athletic heart. For an athlete, the typical resting heart rate is lower, cardiac output can be six to eight times greater, the size and thickness of the heart wall are greater and athletes can show differences on their EKGs as compared to non-athletes [4]. If you see someone who doesn’t know the difference, they many send you for unnecessary testing, provide you with incorrect information or worse: miss something.

I have been there. I passed out in not one but three marathons and went into ventricular tachycardia before I was able to find the right cardiologists to help me. I had seen other cardiologists and was dismissed because I was “too young and too healthy” to have anything wrong. Don't let this happen to you. Don't hesitate to see someone if you are unsure about what you are feeling. Educate yourself, and if you are not getting answers, then you need to get another opinion! 


1. Maron, BJ. et al. Recommendations and Considerations Related to Preparticipation Screening for Cardiovascular Abnormalities in Competitive Athletes: 2007 Update.



4. Kim, Jonathan. Powerpoint presentation Emory University November 2016. Sports Cardiology-Warning Signs for the Athlete.



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