Published studies have generally looked at the effect of a single dose of propranolol on a beta2 agonist over a relatively short period of time (a few hours). There is a desire to develop long acting bronchodilators that require once daily dosing only. Thus any dual pharmacophore developed is likely to have 24 hour duration of action after a single dose. Therefore to use this method of beta blockade to inhibit beta2 agonist mediated bronchodilation, it is necessary to confirm a dosing regimen of propranolol that has acceptable tolerability and is effective in blocking the effects of a beta2 agonist over 24 hours. That is the main purpose of this study.