**6. Summary**

Exercise is an important modifiable risk factor that significantly attenuates cardiovascular morbidity and mortality. Physical activity is associated with enhanced cardiorespiratory fitness which significantly attenuates IR, and some of these effects are mediated by augmented endothelial action of insulin. These vascular effects of exercise include an increase in endothelium-dependent vasodilation through increased NO bioavailability, suppression of ET-1, increased capillary density, and reduction in ROS.

Finally, exercise appears to rejuvenate endothelial function by recruitment of exercise responsive EPCs and influences MSC differentiation.
