In light of the striking effectiveness of the DPP lifestyle intervention to prevent diabetes in older people with IGT, the decline in beta-cell function with even normal human aging, and the importance of beta-cell dysfunction in the progression to diabetes, it is of great interest to further define the potential, novel metabolic effects of exercise training on beta-cell function, particularly in the aging population. This project may provide initial steps to further determine the mechanisms whereby lifestyle changes prevent diabetes. This would provide critical information needed to translate research findings into clinical practice in order to prevent diabetes in the aging veteran population.