Physiologic adaptations to prolonged high-intensity exercise training in patients with coronary artery disease

Exercise training elicits numerous beneficial adaptations in patients with coronary artery disease (CAD), but until 10 yr ago these adaptations were generally believed to be peripheral adaptations rather than improvements in myocardial blood supply. However, animal models of CAD have been shown to elicit improvements in myocardial blood flow and left ventricular performance with prolonged, intense exercise training. More recently we have provided electrocardiographic, echocardiographic hemodynamic, and radionuclide evidence of central cardiovascular adaptations in patients with CAD after a year-long program of 1 h of exercise at 70-90% of VO2max 5 d.wk(-1). These training-induced adaptations are consistent with an improvement in myocardial oxygenation and concomitantly an enhanced left ventricular function in these patients. This program also resulted in improvements in glucose tolerance, insulin sensitivity, and plasma lipoprotein-lipid profile. We have also shown that these beneficial cardiovascular and metabolic adaptations are maintained during six additional years of training in patients with CAD. These results do not imply that all patients with CAD should initiate such an intense training program, but rather that, in selected patients undergoing a training stimulus well in excess of that conventionally prescribed for coronary patients, the training-induced adaptations may be substantially greater than previously believed.