Figure 1

Study design. Symptom-limited incremental cycle exercise testing was performed at screening to determine maximum work rate. Constant work rate exercise testing at 75% of symptom-limited maximum work rate was conducted pre-dose at Visits 1 and 3 (baseline), and at 3 h post-dose at Visits 2 and 4. Spirometry was performed pre-dose at Visits 1 and 3 (baseline) and at Visits 2 and 4; plethysmography was performed pre-dose at Visits 1 and 3 (baseline), and at 2 h post-dose at Visits 2 and 4. BID, twice daily.