Comparison of Continuous and Intermittent Multistage Maximal Exercise Testing During Beta-Adrenoceptor Blockade in Physically Active Men

Abstract

Cardiorespiratory responses of 11 healthy males were studied, with placebo and propranolol, during a continuous and an intermittent multistage maximal treadmill test. With placebo, equivalent maximal heart rates were attained for the disparate test modes, and the intermittent protocol yielded a slightly higher (2%, P < 0.01) maximal O₂ consumption. In contrast, during beta-adrenoceptor blockade, higher maximal heart rates (5.1%, P < 0.01) and O₂ consumptions (4.4%, P < 0.02) were reached with intermittent compared with continuous testing. Values were, however, markedly lower (P < 0.001) for both protocols than with placebo. These results demonstrate that the precise degree of attenuation of maximal heart rate and O₂ consumption observed in physically active persons receiving propranolol is partly dependent upon the actual test protocol utilized. Furthermore, the present data suggest an advantage for intermittent testing when accurate evaluation of the maximal cardiorespiratory capacity is desired in such individuals.

propranolol - maximal heart rate - maximal O₂ consumption - exercise protocol