The effect of short-term aerobic exercise on vascular function of young individuals with a family history of hypertension was investigated. Thirty young men with a family history of hypertension were randomly assigned to either an exercise (n=15) or control (n=15) group. Exercise subjects performed 30 min of supervised cycle training at 65% of their maximal oxygen uptake (VO(2max)), three times per week for 4 weeks. Control subjects were asked to maintain their normal levels of physical activity. Peak leg and forearm blood flow were assessed using plethysmography and was determined as the highest blood flow following 5 min of reactive hyperemia. Cardiopulmonary baroreceptor (CPBR) sensitivity was measured using lower body negative pressure (LBNP) for 5 min at -20 mm Hg. CPBR was determined by calculating change of stroke volume and forearm vascular resistance at baseline and during LBNP. Carotid baroreceptor (CBR) sensitivity was assessed using neck suction at -20, -40, -60 and -80 mm Hg pressures, and was determined from RR interval divided by systolic blood pressure. Augmentation index (AIx), a measure of arterial stiffness, was assessed using applanation tonometry and was calculated as the ratio of augmented pressure and pulse pressure. The major findings were that the exercise group showed increase in leg vasodilation, reduction in AIx and increase in VO(2max) compared with the control group (P<0.05). However, there was no significant change for CPBR and CBR. A short-term moderate-intensity aerobic exercise intervention in young men with a family history of hypertension significantly reduced arterial stiffness and increased aerobic fitness.