Too much of a good thing? Competitive athletes face higher risk of irregular heartbeat

Every two years, we watch world-class athletes compete in the Olympic Games. These superb competitors are at the top of their game physically. They are role models for competitive athletes who dedicate themselves to intensive exercise to achieve personal fitness highs. They appear to be the epitome of health—but looks can sometimes be deceiving.

Conventional wisdom holds that exercise is good for your heart and for the most part, it is. Study after study has supported this thinking. But, when it comes to ultra-athletes, an old saying comes to mind: “There can be too much of a good thing.” For many years we’ve recognized ultra-athletes are at higher risk of developing atrial fibrillation (AFib), compared to individuals who do moderate to light exercise.

What is atrial fibrillation?

AFib is the most commonly diagnosed abnormal heart rhythm. AFib occurs when the normal electrical impulses in the upper chambers (the atria) are disrupted, and a chaotic electrical pattern propagates instead. This causes the lower chambers (the ventricles) to beat irregularly, and often too quickly. It can cause symptoms such as:

• Palpitations
• Fluttering sensation in the chest
• Breathing troubles
• Lightheadedness
• Chest pain

Perhaps more importantly, there is a four to five times higher risk of stroke in someone with atrial fibrillation, which is usually managed with blood thinner medications.

Why ultra-athletes are at risk for AFib

People who develop AFib are usually older and have coronary artery disease, valvular disorders or other types of heart disease. However, AFib can also occur in younger through middle-aged adults whose fitness level is well beyond that of the average person.

Several studies have found the rate of AFib in ultra-athletes is two to ten times greater than in sedentary individuals. It’s important to keep in mind that there is no established exercise threshold above which fitness-related arrhythmias occur, making it more difficult for physicians to give absolute guidelines to ultra-athletes.

During my years in practice, I’ve seen many adult ultra-athletes who have presented with symptoms of AFib. While most are older—in their 50s, 60s and 70s—I have also seen patients in their 30s and 40s. After studying ultra-athletes who develop AFib, we’ve learned that having elevated heart rates for an extended period of time over many years may cause a degree of fibrosis, or scarring in the atria. Ultra-athletes also tend to have lower than normal heart rates, creating the opportunity for other parts of the atria to generate heart beats, outside the sinus node, which is the part of the heart that usually sets the heart rate.

One of my past patients is a perfect example of AFib in ultra-athletes. He is a 57-year-old man who presented with episodes of palpitations and shortness of breath. Using his smartwatch to record his own EKG during his symptom episodes, he was diagnosed with atrial fibrillation. He competed in triathlons several times per year, a hobby he has had for 30 years. In consultation with the patient, he selected ablation as the preferred treatment. His procedure was approximately 90 minutes long and he returned home later that day. Since his ablation two years ago, he has done well, has not had any recurrent symptoms and has not been on medical therapy for his AFib. He has been able to return to the active lifestyle that he loves.

Treatment options for atrial fibrillation

There are many options available to manage atrial fibrillation. The most important is prevention—controlling your other medical conditions including high blood pressure, sleep apnea, obesity, diabetes, etc. In order to treat the atrial fibrillation more directly, we generally prescribe medications or perform a minimally invasive ablation procedure.

While both medications or an ablation procedure are reasonable options to treat AFib, I find that ultra-athletes often experience more side effects from the medications, which tend to lower the heart rate, so many tend to prefer the procedural option. Ablation involves inserting a catheter through a blood vessel into the heart. Sensors on the tip of the catheter are used to identify and block the specific electrical triggers for AFib. These triggers can be blocked by either delivering radiofrequency energy (heat) or cryoablation (cold). Both methods are highly effective at reducing symptomatic episodes of AFib in the future.

Detecting and preventing atrial fibrillation

Fortunately, ultra-athletes are very attuned to their bodies. So, they are often aware of anything out of the ordinary. In addition to symptoms, new wearable digital monitoring technology, such as a smartwatch, enables these ultra-athletes to monitor their heartbeats and record their own EKGs. This gives us an early insight into their overall cardiac health.

As with much medical research, most of the studies conducted on this topic have focused on men. Hence, we don’t know if this condition also affects female ultra-athletes to the same degree as their male counterparts, but ongoing research studies seek to answer this question.

How much exercise is too much?

Ultimately, it is all about moderation. Too little exercise increases risks of cardiovascular disease, diabetes mellitus, high blood pressure and obesity. Too much exercise and there is a higher chance of atrial fibrillation. The American Heart Association recommends getting at least 150 minutes of moderate physical activity per week. This can include activities such as:

• Brisk walking
• Water aerobics
• Dancing
• Gardening
• Tennis
• Riding a bicycle at a modest pace. 

If you are inclined for more intense physical activity, the AHA recommends at least 75 minutes per week. Examples of intense activity include:

• Hiking uphill
• Running
• Swimming laps
• Jumping rope
• Riding a bicycle quickly
• Heavy continuous yardwork

If you suspect you are experiencing irregular heartbeats, follow up with your primary care physician immediately. He or she may refer you to an electrophysiologist for evaluation and treatment.

Worried you might have AFib? Download our AFib treatment guide today.