The Runner's Heart

Sorting Out Running's Risks and Benefits for the Heart

September 1, 2003

Few cases in medicine are more poignant than the sudden death of a young, fit athlete. Young athletes, under the age of 35, suffer fatal cardiac arrhythmias primarily because of congenital defects, abnormalities in the structure or electrical pathways of the heart that are present from birth. In contrast, in athletes over the age of 35, sudden death is caused predominantly by heart attacks, caused by the accumulation of atherosclerosis in the coronary arteries.

The sudden death of a young athlete is very rare. One of the best assessments of the prevalence of such deaths comes from a carefully collected set of cases comprised of competitive athletes, under the age of 35, who died in the United States between 1985 and 1995. Cases were excluded if the athletes had a known history of drug use or if no autopsy was performed. A total of 158 cases were identified from the news media, registries of sports injuries and cardiovascular pathology, and communications with schools and colleges. Running, basketball and football were the sports most commonly associated with sudden death.

While almost none of the young athletes had known heart conditions at the time of death, autopsy examinations identified cardiac abnormalities in nearly every case. The disorders that triggered sudden death were diverse, affecting the heart muscle, the coronary arteries that feed blood to the heart muscle, the electrical pathways in the heart, or the heart valves. The most common cause was hypertrophic cardiomyopathy, a condition affecting 1 in 500 people that causes an abnormal thickening of the heart muscle.

A concerning symptom, such as the sudden loss of consciousness during exertion, warrants careful investigation. Faced with a new diagnosis, many young athletes are reluctant to accept any restrictions on their ability to train and compete. Love of the sport, the thrill of competition, and the drive to improve lead many to ignore warning signs.

The American Heart Association has issued official guidelines for the screening of young, competitive athletes which recommend a mandatory medical examination prior to participation in organized scholastic sports. Many cardiac disorders can be diagnosed by a careful history and physical. Some conditions may still be missed, but the use of further testing, such as an electrocardiogram (EKG) or an echocardiogram, for every young athlete is not considered feasible or appropriate.