In brief: Beta-blockers and exercise training are recommended for treating cardiovascular disease and hypertension, and researchers have tried to determine the interaction of these two treatment modalities. Data from four studies conducted on 93 subjects over the past five years show that beta-blockade exerts a differential effect on the exercise capacity of subjects of different levels of health and fitness: It increases the capacity of angina patients; decreases the capacity of highly trained, fit individuals; and has little or no effect on the capacity of healthy, untrained individuals.