Training Response in Patients With Coronary Artery Disease Receiving β-Adrenergic Blocking Drugs With or Without Partial Agonist Activity

It has been suggested that beta-adrenoceptor blocking agents may impair the training response but that this may not occur if the agent possesses partial agonist activity (PAA). We tested these hypotheses in 39 male patients, following myocardial infarction or coronary artery bypass graft surgery, who underwent structured exercise training three times a week for 8 weeks. Exercise tolerance was assessed before training, within 5 days after training, and again 2 weeks after training in 14 patients receiving acebutolol (with PAA), 12 patients receiving sotalol (without PAA), and 13 patients receiving placebo. Blood levels of both agents confirmed that steady states sufficient to produce beta-blockade were achieved during training. All three groups of patients demonstrated statistically significant improvements in exercise duration, energy expenditure, heart rates attained performing equal work loads, and percentage functional aerobic impairment. No significant differences were found between the three groups before or after training. We conclude that beta-adrenoceptor blocking agents in standard therapeutic doses do not cause impairment of exercise training and that PAA affords no enhancement of the training response.