Effects of cardioselective and nonselective beta-adrenergic blockade on the performance of highly trained runners

Twenty-five highly trained runners with a maximal oxygen uptake (V0₂ Max) of 64.7 ± 4.3 mi · kg^-1 · min^-1 were administered clinically equivalent doses of a nonselective (propranolol) and a cardioselective (atenolol) β-blocking agent as well as a placebo. The subjects performed a horizontal treadmill test on the eighth day and a 10-km track race on the tenth day of each treatment. Beta blockade decreased submaximal heart rate and propranolol caused the largest decrease. Beta blockade caused a decrease in maximal heart rate, V0₂ Max, maximal ventilation, maximal respiratory exchange ratio and treadmill time. Propranolol caused a greater decrease than atenolol in each of these values. The 10-km race times were significantly slower during β blockade, and propranolol race times were significantly slower than atenolol race times. It is concluded that the performance of highly trained distance runners is significantly altered by β-adrenergic blockade and that nonselective agents reduce performance to a greater extent than cardioselective agents.