Exercise training: can it improve cardiovascular health in patients with type 2 diabetes?

Exercise training is an essential component of the management of patients with type 2 diabetes Most exercise training studies of patients with diabetes have focused on glycaemic control and less on the effects of exercise on cardiovascular health. Yet there are data from a variety of studies that provide strong, albeit not perfect, evidence that exercise training should be a standard of care not only for glycaemic control but for also improving the cardiovascular system in these patients. Type 2 diabetes is associated with dysfunction and failure of various organs, especially the heart and peripheral blood vessels. Both insulin resistance and β cell dysfunction are contributing factors to the disease,1,2 as are environmental influences and genetic factors.3,4 It has also become clear that the increasing prevalence of obesity1 and a sedentary lifestyle5 are also key contributors to the rising prevalence of type 2 diabetes in the United States and throughout the world. Two other metabolic conditions that precede the development of diabetes also have adverse effects on cardiovascular health and may also be prevented or delayed by regular exercise. Pre-diabetes is a metabolic condition that is between normal glucose homoeostasis and diabetes,6 and its prevalence in 2000 was estimated at nearly 12 million adults in the United States.7–9 The metabolic syndrome, which considerably increases the risk of developing diabetes, also stems from an underlying abnormality in insulin resistance.10–13 Although type 2 diabetes increases the risk of microvascular complications such as retinopathy and nephropathy,14,15 most diabetic patients die from macrovascular complications including coronary artery disease and stroke, with an increased risk of these conditions of 200–400%.16,17 Even before glucose concentrations reach the diagnostic threshold for diabetes, 25% of newly diagnosed patients may already have appreciable cardiovascular …