Distance running in the 1980s: cardiovascular benefits and risks.

Although within the capacity of perhaps one to two percent of highly motivated patients after myocardial infarction, long-distance and marathon running do not confer on normal subjects immunity from coronary atherosclerosis or freedom from high grades of ventricular ectopy during running and nonrunning activities. The presence of significant coronary heart disease does not preclude participation in long-distance and marathon running, provided appropriate safety precautions are taken. There is no conclusive proof that the long-term prognosis is improved by long-distance or marathon running or by increasing the intensity of training above the generally accepted level of 60 to 80 percent of VO2 max. Marathon running for coronary patients and for coronary-prone persons remains experimental and awaits further scientific evaluation employing a prospective randomized study of subjects with angiographic proof of significant coronary artery disease.