Controversy exists concerning the effects of acute beta-adrenergic blockade on ventilation during exercise. Hence, the purpose of this study was to determine the effects of acute beta blockade on ventilation and gas exchange during incremental exercise. Nine male subjects underwent incremental exercise on a cycle ergometer (30 W·min-1) to exhaustion, with one trial being performed 60 min after the subject ingested propranolol hydrochloride (Inderal 1 mg·kg-1 BW) while the second test served as control. The treatment order was counterbalanced to preclude any ordering effect on the results, and 1 week separated the tests. Ventilation and gas exchange were monitored by open circuit techniques. No difference (p > 0.05) existed in V̇e, % Hb sat, V̇co2, ventilatory threshold, and V̇e/V̇co2 between treatments at the same exercise stage. V̇o2 max was lowered from 3.82 to 3.26 1·min-1 (p < 0.05) and HRmax was reduced from 190 to 150 bpm (p < 0.05) as a result of beta blockade. These data suggested that acute beta blockade had no effect on exercise ventilation, but decreased HRmax at comparable work rates. In addition, V̇o2max and exercise time to exhaustion were hindered, probably due to beta blockade limitation of HRmax, and, thus, oxygen transport.
|Original language||English (US)|
|Number of pages||5|
|Journal||Aviation Space and Environmental Medicine|
|State||Published - Jan 1 1988|
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health