Backgrounds:Improvement of exercise capacity by training is more prominent in the obese individuals who have had sedentary life style. The aims of this study were to assess cardiovascular changes occurring in response to military training in young obese men. Methods: Sixteen obese (BMI>25 kg/m2), otherwise healthy subjects in age ranging from 20 to 21 years were enrolled. They completed the 5 weeks training which was consisted of aerobic and anaerobic exercise with increasing intensity. To assess exercise capacity, the running time of 1,500 m of each subject were measured before and after training. Serum metabolic markers and comprehensive echocardiograms were obtained at baseline and after 5 weeks of training. Results: Training significantly improved exercise capacity. Body mass index and body fat mass were reduced. Adiponectin was markedly increased with favorable changes of lipid profile. With marked improvement of exercise capacity, there were significant changes suggestive of improved diastolic function. Conclusion: Exercise elicited metabolic changes and improvement of diastolic function in young obese individuals, which suggests that diastolic dysfunction is related to exercise intolerance in obese individuals.