The purpose of this investigation was to study exercise-induced hypertension after surgical repair of coarctation of the aorta (CoA). Groups of 27 patients with CoA and 27 healthy control subjects, 6-21 years old, were exercised to exhaustion using the Bruce protocol. Fourteen patients had undergone surgery during the first year of life (group A), and 13 patients had been operated on later (group B). The pulse rate and systolic blood pressures (BP) in the arm and leg were measured before, during, and after exercise to evaluate changes in the BP and the arm/leg BP gradient with exercise. The systolic BP was significantly higher in the patients than in the controls at all stages of the exercise test (p