Objective To assess the impact of maximal fat oxidation intensity(FATmax) exercise on arterial stiffness in overweight/obesity young men.Method Thirty two overweight/obesity young men (BMI≥25 kg/m2) without the habit of doing exercises,were divided into an exercise group (n=16) and a control group (n=16) randomly.The exercise group completed a 12-week walk/run(FATmax intensity,3-5 times/week,40-60 min/time) intervention,while the control group maintained normal life style without regular exercise.The body composition,cardiopulmonary function (VO2max),C reactive proteins (CRP) and blood hemodynamic were measured,and the brachial-ankle pulse wave velocity(baPWV) was observed to assess the arterial stiffness before and after the 12-week intervention.Results Significant decrease was observed in the average weight,body mass index,body fat mass,body fat percentage,baPWV,CRP,platelet/lymphocyte ratio (PLR) and neutrophil/lymphocyte ratio (NLR) (P＜0.05),while significant increase was found in the average VO2max and HDL-C(P＜0.05) after the training.After the intervention,the change in baPWV(△) was positively associated with △ CRP(r=0.604),△ NLR(r=0.535) and △ WBC (white blood count) (r=0.406) (P＜0.05,n=32),but negatively correlated with △ VO2max (r=-0.660,P＜0.05,n=32).Conclusion FATmax intensity aerobic exercise is effective to downregulate the inflammation,and improve aerobic fitness and vascular function.However,the potential mechanism of arterial stiffness improvement following exercise needs further study.