Athlete's heart refers to the normal changes that the heart undergoes in people who regularly do strenuous aerobic exercise (for example, very well conditioned athletes) and, to a variable extent, in those who do extensive weight training.
In a person with athlete's heart, the heart is larger and its walls thicker than in a nonathlete. The chambers inside the heart get somewhat larger. This increase in size and thickening of walls allows the heart to pump substantially more blood per heartbeat. The larger volume of blood with each heartbeat allows the heart to beat slower, which results in a slower, stronger pulse (which can be felt at the wrist and elsewhere on the body) and sometimes in a heart murmur. These murmurs, which are specific sounds created as blood flows through the valves of the heart, are perfectly normal in an athlete and are not dangerous. The heartbeat of a person with athlete's heart may be irregular at rest but becomes regular when exercise begins. Blood pressure is virtually the same as in any other healthy person.
The person has no symptoms. Doctors usually suspect athlete's heart during routine screening or when the person is being evaluated for unrelated symptoms.
Most athletes do not require extensive testing, but doctors usually do electrocardiography (ECG) because it is important to ensure that the person does not have a heart disorder. A variety of changes are detectable on an ECG. These changes would be considered abnormal in a nonathlete but are perfectly normal in an athlete. If the person has chest pain or other symptoms of a heart disorder, more extensive testing is needed, such as echocardiography and exercise stress testing.
When an athlete stops training, athlete's heart slowly disappears—that is, heart size and heart rate tend to return gradually to those of the nonathlete.
Athlete's heart is not thought to affect health in any way. The rare sudden death of an athlete (see see Sudden Cardiac Death in Athletes) is usually due to underlying heart disease that was not previously detected rather than to any danger resulting from athlete's heart.
Last full review/revision April 2013 by Robert S. McKelvie, MD, PhD, MSc