OBJECTIVES We sought to investigate whether plasma aldosterone-to-renin ratio (ARR) is associated with left ventricular (LV) longitudinal functional reserve and exercise capacity in controlled hypertensive patients without overt LV hypertrophy. BACKGROUND Aldosterone excess is associated with an increased rate of cardiovascular events in hypertensive patients. METHODS After 24-hour blood pressure (BP) recordings and conventional echocardiography, plasma aldosterone concentrations (mg/dl) and renin activities (ng/ml/h) were measured. Enrolled subjects (mean age 56 짹 8 years, 27 males) were divided into two groups according to ARR as group I (ARR<30, n=37) and group II (ARR���30, n=18). Supine bicycle exercise echocardiography with simultaneous respiratory gas analysis was performed. Mitral inflow and annular velocities were measured at rest and during exercise. RESULTS Despite similar 24-hour BP, LV mass index was significantly higher in group II (88.9짹16.3 vs 101.2짹18.5 g/m2, p=0.024). Systolic mitral annular velocity (S���) was significantly lower in group II (6.5 짹 1.3 vs 5.7 짹 0.6 cm/s, p=0.006). Longitudinal diastolic functional reserve index at 25W- and 50W-exercise, defined as ��E���(change from E���base) x E���base (early diastolic mitral annular velocity at base) of group II was significantly lower than that of group I (15.7 짹 10.6 vs 9.7 짹 7.2, p=0.028; 21.2 짹 10.5 vs 13.0 짹 7.3, p=0.009, respectively), accompanying poorer exercise capacity (VO2max: 22.6 짹 5.3 vs 19.4 짹 6.0 ml/kg/min, p=0.031). CONCLUSIONS In hypertensive patients without overt LV hypertrophy, increased plasma ARR was associated with poor exercise tolerance, increased LV mass, impaired LV longitudinal function and functional reserve during exercise.