PURPOSE: This study aimed to compare the acute effects of high-intensity interval exercise (HIIE) with moderate-intensity continuous exercise (MICE) on arterial stiffness, cerebral blood flow and cognitive function in young smokers. METHODS: Young smokers (23.1 years & 7.2 pack years) were randomly assigned to either MICE (n=5) or HIIE (n=4) group. MICE was implemented at 70% of HRmax for 30 minutes. HIIE was performed at 70% and 90% of HRmax for 24 minutes. Central artery stiffness was assessed by aortic pulse wave velocity (cfPWV), augmentation index (AIx) at pre and post-exercise, and 30 minutes, 1 hour, 2 hours, 24 hours following the exercises. Cerebral blood flow was continuously monitored using near-infrared spectroscopy technique before and during exercise, and at 30 minutes, 1 hour, 2 hours, and 24 hours following the exercises. Cognitive function was assessed by Stroop Color-Word test at pre-exercise, and 30 minutes and 24 hours following the exercises. RESULTS: There was no significant group by time interaction in cfPWV,AIx, cerebral blood flow (HbO2) level, and cognitive function. Compared with MICE, cfPWV was increased (p=.01) at 30 minutes but AIx was decreased (p=.02) at 1 hour following HIIE. When MICE and HIIE combined, arterial stiffness and cerebral blood flow measures, and cognitive function parameters were improved following even one-bout of exercise (p≤.049). Change in AIx was associated with change in cognitive function at 30 minutes following the exercises (r=.69, p=.06). CONCLUSIONS: Even one-bout of either MIIE or HIIT acutely improves aortic wave reflection, cerebral blood flow and cognitive function in young smokers. The intensity of aerobic exercise does not seem to make meaningful differences in the positive effects on arterial stiffness, cerebral blood flow, and cognitive function in young smokers if both exercises have the same volume.