Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Abstract

The effects of propranolol 80 mg orally were compared with those of placebo on the response to a stepwise increasing exercise test in 17 healthy and physically untrained volunteers, of whom eight were female. Propranolol showed no significant effects on maximum work rate or perceived exertion rate. However, submaximal O2 uptake, CO2 output and minute ventilation tended to be lower after propranolol than after placebo. It is concluded that in subjects with a low work capacity, beta‐adrenoceptor blockade does not impair maximal exercise capacity. The mechanisms underlying changes in respiratory response to exercise after propranolol are not fully explained. However, changes in substrate utilisation, the reduction in cardiac output and an alteration in respiratory drive may all be involved.

The effects of beta‐adrenoceptor blockade on breathing during progressive exercise in normal man.

“…The principle finding of this paper is to confirm the results of Violante et al (1984) that ,-adrenoceptor blocking drugs reduce minute ventilation at submaximal but not at maximal exercise levels (above 150 watts). In our study the effects were seen most clearly with the cardioselective drug atenolol.…”

“…The results with propranolol showed the same trend but with more scatter, possibly because of the much greater variation in plasma levels known to occur follow-ing single oral doses of propranolol than with atenolol. However, the fact that Violante et al (1984) used propranolol supports the view that the effect in depressing ventilation is not related to cardioselectivity or lipid solubility. Twentyman et al (1981) also found a tendency (not statistically significant) for VE to be reduced during progressive exercise following propranolol but also found that the effect was time dependent, ventilation being depressed early in submaximal exercise but not as the steady-state is approached.…”

“…Similarly small and frequent adjustments in exercise load were used in the negative study reported by Leitch et al (1980). Although Violante et al (1984) used only 25 watt increments they emphasize that their subjects were physically untrained unlike those of Pearson et al (1979). There are probably also direct effects of 1Badrenoceptor blocking drugs on the chemical drive to breathing.…”

“…Enhanced hypoxic drive during exercise (Cunningham et al, 1968) may have as its basis increased sympathoadrenal activity. However, several studies have failed to demonstrate an effect on minute ventilation during graded exercise in normal subjects (Pearson, et al, 1979;Leitch et al, 1980;Petersen et al, 1983;O'Neill et al, 1984;McLeod et al, 1985) whereas others have shown reductions in minute ventilation after propranolol at submaximal levels of exercise (Twentyman et al, 1981;Violante et al, 1984).…”

Effects of arotinolol on exercise capacity and humoral factors during exercise in normal subjects

“…However, beta blockers are a poor choice in patients who wish to engage in an exercise program because they interfere with exercise performance. Most studies have shown that nonselective beta blockade results in a 6-14% reduction in maximal oxygen uptake (V02 max) [1,2], while few studies have reported that beta blockers do not have such an effect [3]. On the other hand, beta l-selective blockade also decreases VO 2 max by 11% [4,5].…”