 All subjects will be screened against the inclusionexclusion criteria for enrollment. A computer-generated randomization code will be created by the Amphastar Pharmaceuticals IT Department, so that each enrolled subject will receive all three double-blinded treatments in randomized sequence. Each treatment is followed by a standardized exercise challenge and a series of FEV1 measurements during the 90 min post-exercise period. The three crossover Treatment Arms are: 