The aim of this study was to compare the effects of nifedipine coat-core (once daily formulation) and amlodipine on systemic arterial stiffness in patients with hypertension. Study drugs were assigned by the randomized open-label crossover method. After the blood pressure was maintained below 130/85 mm Hg for 8 months by treatment with either drug in 48 hypertensive patients (aged 63.2+/-6.9 years; 64.5% men), they were switched to the other drug for another 8 months. The blood pressure, heart rate, plasma catecholamine level and brachial-ankle pulse wave velocity were measured before and after a bicycle ergometer testing. Heart rate recovery was calculated from the change of the heart rate after treadmill exercise testing. The high-frequency and low-frequency components of the heart rate variability spectrum were analyzed from 24-h Holter electrocardiograms. The change of blood pressure after exercise testing showed no significant difference between the two medications. However, the increases of heart rate, noradrenalin and branchial-ankle pulse wave velocity after exercise were significantly smaller with nifedipine treatment than with amlodipine (P=0.0472, P=0.006 and P=0.0472, respectively). Heart rate recovery was significantly faster with nifedipine treatment (P=0.0280). The nighttime high-frequency component of heart rate variability was significantly larger after nifedipine treatment than after amlodipine (P=0.0259), while the nighttime low/high-frequency ratio was significantly smaller with nifedipine (P=0.0429). Nifedipine reduced functional arterial stiffness and improved heart rate recovery by altering the autonomic activity balance in hypertensive patients.