The exercise tests performed by 197 patients aged 65 years or more (mean age 68.8) have been reviewed, including 43 healthy subjects, 20 with high blood pressure, 10 with mitral valve disease and 125 with demonstrated coronary artery disease. All tests were done on an electrical cycloergometer, with load increases of 30 W every 3 min. Eighty-four (42.6%) achieved at least 85% of their maximal predicted heart rate. The reasons for non-achievement of this heart rate were limitation by symptoms (30.2%), betablocker therapy (25.8), exhaustion (20.2%), pain in lower extremities (14%) and non-adaptation to cycloergometer (10%). The maximum load achieved and the duration of exercise were significantly lower in mitral and coronary patients. Functional aerobic capacity was decreased in coronary and mitral patients. The VO2 max was directly determined in 45 patients. Mean values (ml kg-1 min-1) were 33.3 +/- 3.5 in normals, 15.4 +/- 6.2 in coronary and 15.8 +/- 4.1 in mitral patients. The incidence of arrhythmias during exercise was higher in hypertensive (55%) than in mitral (40%), normal (33.3%) and coronary patients (32.8%). In 5 patients the test had to be interrupted because of ventricular tachycardia. The yield of ST depression (greater than 0.1 mV) or elevation (greater than 0.2 mV) in the diagnosis of coronary artery disease was 0.62 sensitivity and 0.93 specificity. We conclude that stress test is a useful tool in cardiovascular diagnosis among older patients.(ABSTRACT TRUNCATED AT 250 WORDS)