,&Blockade reduces tidal volume during heavy exercise in trained and untrained men

tidal volume during heavy exercise in trained and untrained men. J, Appl. Physiol. 62(S): 1819-1825, 1987.-The effects of /?-blockade on tidal volume (VT), breath cycle timing, and respiratory drive yere evaluated in 14 endurance-trained [max-imum 0, uptake (VO, ma = ) ~65 ml n kg- ’ l min-‘1 and 14 untrained. wo 2max-50 ml I kg- ’ l rein-l) male subjects at 45, 60, and 75% of unblocked VO, mar and at VO, maI * Propranolol (PROP, 80 mg twice daily), atenolol (ATEN, 100 mg once a day) and placebo (PLAC) were administered in a randomized double-blind de-sign. In both subject groups both drugs attenuated the increases in VT associated with increasing work rate. CO, production (ho,) was not changed by either drug during submaximal exercise but was reduced in both subject groups by both drugs during maximal exercise. The relationship between minute ventilation (i7E) and VCO ~ was unaltered by either drug in bot