Frequent or repetitive exercise-induced ventricular ectopic beats are often considered a marker for serious cardiac disease or sudden death, or both. However, the prognostic value of these arrhythmias in an unreferred asymptomatic community-dwelling population over a broad age range is unknown. Of 1,160 subjects aged 21 to 96 years who underwent maximal exercise treadmill testing an average of 2.4 times, 80 (6.9%) developed frequent (greater than or equal to 10% of beats in any 1 min) or repetitive (greater than or equal to 3 beats in a row) ventricular ectopic beats on at least one test. These 80 individuals were significantly older than the group without such arrhythmia (63.8 +/- 12.5 versus 50.0 +/- 16.1 years, p less than 0.0001). A striking age-related increase in the prevalence of frequent or repetitive exercise-induced ventricular ectopic beats was seen in men (p less than 0.0001) but not in women. The prevalence of electrocardiographic abnormalities at rest, exercise-induced ST segment depression and thallium perfusion defects, duration of treadmill exercise, maximal heart rate, systolic blood pressure and rate-pressure product did not differ between these 80 study subjects with frequent exercise-induced ventricular ectopic beats and a control group matched for age and gender. Furthermore, the incidence of cardiac events (angina pectoris, nonfatal myocardial infarction, cardiac syncope or cardiac death) (10% versus 12.5%) as well as noncardiac mortality (each 7.5%) was found to be similar for the study and control groups, respectively, over a mean follow-up period of 5.6 years. No study subjects required antiarrhythmic drugs over this time interval.(ABSTRACT TRUNCATED AT 250 WORDS)