Very good question. This is a long answer but bear with us because to understand it, FX needs to give you some background.
An enlarged heart isn't a condition in itself, but a symptom of an underlying problem that is causing the heart to work harder than normal. The range of underlying problems falls generally into two main categories - pathological (linked to actual disease of the heart muscle disease) and physiological (linked to other causes which are overworking the heart muscle, such as high blood pressure or thyroid diseases). In some cases, an enlarged heart is asymptomatic (has no symptoms). When symptoms do occur, it may be because the heart fails to pump blood effectively and this leads to a syndrome known as congestive heart failure. Symptoms may include:
Some of the many causes of enlarged heart include:
An enlarged heart is diagnosed using a number of tests including:
Treatment depends on the underlying cause but can include:
So to answer your question about athletes and enlarged hearts, here is some more specific information.
"Athletes heart" is a common term for an enlarged heart that is usually associated with repeated strenuous exercise. This is normal and there is usually no danger of heart problems. "Athlete's heart" becomes dangerous when the muscle wall of the lower chamber of the heart (Cardiomyopathy) or the walls of the heart's chambers thicken abnormally (Hypertrophic cardiomyopathy).
Hypertrophic cardiomyopathy (called athletic heart muscle disease) usually appears in young people, often in athletes. Due to the increased workload required of it, the heart will increase physiologically by enlarging its chambers and muscle mass, thus increasing the volume of blood pumped per stroke. As a result, the heart has to contract less frequently and at rest will beat as few as 40 times per minute. The average number of beats per minute in a non "athlete's heart" is 70 beats.
The heart of a person with cardiomyopathy is enlarged in a bad way, and there's virtually no place for the blood to go. At a certain point, the heart's chambers (the septum) may become so thickened that it blocks the flow of blood through the lower left chamber (left ventricle). The thickened wall may push on the heart valve between the two left heart chambers (mitral valve), making it leaky. The thickened muscle walls also prevent the heart from stretching as much as it should to fill with blood. This leads to heart failure
The cause of hypertrophic cardiomyopathy is not known. In about one-half of cases, the disease is inherited. An abnormal gene has been identified in these patients. In cases that are not hereditary, a gene that was normal at birth may later become abnormal.
People of any age can develop hypertrophic cardiomyopathy. Often people with hypertrophic cardiomyopathy have no symptoms. Unfortunately, the first sign of the condition may be sudden death caused by an abnormal heart rhythm. When symptoms do appear, they include shortness of breath on exertion, dizziness, fainting, fatigue, and chest pain. The American Heart Association reports that 36% of young athletes who die suddenly have probable or definite hypertrophic cardiomyopathy.
If you are concerned about this or any heart condition, please discuss it with your family doctor.