In spite of appropriate pharmacologic therapy, many hypertensive patients develop an abnormal left ventricular relaxation with preserved systolic function. This cardiac dysfunction increases the risk of cardiovascular complications. The authors assessed the therapeutic effects of an intervention with exercise training and weight reduction in patients with pharmacologically well-treated hypertension who had abnormal left ventricular relaxation with normal systolic function. Eighty-eight (44%) of 202 medically treated hypertensive patients had abnormal ventricular relaxation with normal ejection fraction. These patients were randomized to either a 6-month intervention program (cycle ergometer training twice a day for 5 days a week and a hypocaloric diet) or a control program (unchanged pharmacologic therapy without exercise and diet. Body weight, blood pressure, New York Heart Association class, glomerular filtration rate, and exercise capacity and workload were measured. Cardiac function was assessed by measuring N-terminal pro-B-type natriuretic peptide values, the electrocardiographic QT dispersion interval, and echocardiography (left atrial size, Doppler-derived E/A ratio, and mitral deceleration time). Physical exercise with weight reduction reduced blood pressure, decreased cardiovascular risks, and improved abnormal left ventricular relaxation. Measuring left atrial size is the best method for assessing changes in left ventricular relaxation with preserved systolic function. J Clin Hypertens (Greenwich). 2011;13:23–29. ©2010 Wiley Periodicals, Inc.