A treadmill exercise test response may become positive because a diagnostic electrocardiographic ST-segment shift occurred during exercise, or, less often, because it occurred only during the recovery period after exercise had been completed. Factors that may be related to these 2 different responses in subjects enrolled in the Program of Surgical Control of Hyperlipidemia were investigated. No differences were found with regard to age, sex, level or location of Minnesota electrocardiographic Q-QS codes, number of narrowed coronary arteries, presence of collateral coronary artery circulation, ejection fraction, number of abnormally moving left ventricular wall segments, heart rate, systolic and diastolic blood pressure, double product, total exercise time, exercise-induced angina, or maximally achieved exercise heart rate or double product. Thus, the same significance should be attributed to a recovery-positive as to an exercise-positive treadmill test, and electrocardiographic, hemodynamic and angiocardiographic variables do not distinguish between subjects who exhibit these 2 different responses.