 Increased sympathetic nervous system activity may participate in the pathogenesis and complications of the metabolic syndrome. This Study will use a randomised controlled design to evaluate the effects of pioglitazone treatment on sympathetic activity in middle-aged subjects with the metabolic syndrome.The results will generate new information on the neuroadrenergic effects of thiazolidinediones in this clinical setting. This is relevant to the understanding of the pathophysiology of the metabolic syndrome and to its clinical management. 