Athletic heart syndrome (AHS) is a condition where the heart is enlarged due to frequent, dynamic exercise. Dynamic exercise includes types of cardio workouts like running, swimming, and biking. Here, the heart becomes enlarged because it has to work hard to get enough oxygen to the body during intense workouts. This syndrome can occur in people who perform dynamic exercise more than 5 hours a week. The syndrome is benign (not harmful), but it can be mistaken for or cover up a more serious condition. The symptoms of AHS are very similar to a serious congenital condition called hypertrophic cardiomyopathy, so it is very important for a doctor to confirm that AHS is the cause of the symptoms.
The hearts of those with AHS act in ways that would be concerning if they did not have AHS. AHS is characterized by a very slow heart rate (bradycardia) of 40-60 bpm (beats per minute). This is compared to a normal heart rate of 60-100bpm. Those with AHS also have an enlarged heart (cardiomegaly) and thickening of the muscular wall of the heart (cardiac hypertrophy). Finally, a doctor may be able to hear an irregular sound in the heartbeat (a murmur, specifically called an S3 gallop) when they listen with a stethoscope.
To diagnose AHS, your doctor will perform a physical exam and ask about your workout schedule. In a follow up, they may use an electrocardiogram (EKG) to test your heart’s electrical impulses. A stress test may also be performed. Athletic heart syndrome is not dangerous and signs usually decrease if a person stops exercising. In fact, a doctor may recommend a deconditioning period to verify the symptoms decreased and thus confirm that there are no other underlying heart problems. Treatment for AHS is not necessary. If you have been diagnosed with AHS, talk with your cardiologist (heart specialist) to learn more about AHS. Support groups are a good source of information and can connect you with others living with AHS.