Diuretic therapy and exercise in patients with systemic hypertension.

Twenty patients with uncomplicated systemic hypertension underwent treadmill testing twice during placebo treatment and twice during hydrochlorothiazide treatment. Data were collected at rest, at peak exercise and 10 min after exercise. Serum potassium, magnesium and plasma catecholamines increased significantly with exercise. There was no rebound hypokalaemia during the recovery period. Occasional ventricular premature complexes were recorded in all phases of the study. However, there was no difference in the frequency or complexity of arrhythmias between the placebo and the treatment periods.