RESUMO
Stage fright was used to investigate the mode of action of beta blockers in acute anxiety and on the technical-motor performance of 22 performing string players. They received 100 mg of atenolol or placebo 6.5 hr before performing either in the presence or absence of an audience. Continuous heart rate, stage fright (especially devised rating scale), technical-motor performance (runs of fast notes, trills, vibratos), and urine catecholamine levels were assessed. Before an audience the placebo group showed a significant impairment of technical-motor performance (increase in the relative variance of repeated fast elements of movements: + 25.68%, p less than 0.01) as compared to performance with no audience present; there was a slight but not significant improvement under beta blockade (- 7.48%). Heart rate was significantly lower under beta blockade than under placebo (p less than 0.001). Urine catecholamine levels increased twice as much under beta blockade as under placebo before an audience (p less than 0.01). Beta blockade did not influence stage fright measured before performing, but reduced it (measured immediately after the concert) during the concert. We conclude that the drug was at least partially effective as shown by an improvement in technical-motor performance, and that the beneficial effects of beta blockade in stage fright only involve a peripheral site of action.
