Previous studies suggest that treadmill exercise may be a more relevant exercise stimulus than the cycle ergometer to demonstrate benefits with bronchodilator therapy in patients with COPD. The hypothesis of the study is that patients with COPD will exhibit greater improvements in exercise endurance and breathlessness with arformoterol compared with normal saline during treadmill walking than with cycle exercise.

The study is a randomized trial with crossover of consecutively recruited patients with symptomatic COPD. Each patient will participate in seven visits over a 3-4 week period. At the first visit patients will provide informed consent and then be familiarized with equipment and testing protocols. At visits 2 and 3 patients will inhale 2 puffs of albuterol HFA MDI, and then perform symptom limited incremental exercise on the treadmill or cycle ergometer (randomized order); after a one hour rest, the patient will perform constant work exercise at 80-85% of peak VO2 on the same exercise mode.

At visits 4 - 7, patients will perform PFTs at baseline and at 30 and 120 minutes after inhaling arformoterol or normal saline (randomized order) and then constant work exercise on the treadmill or cycle ergometer (randomized order). Metabolic measurements will be made throughout exercise, and patients will provide continuous ratings of breathlessness and leg discomfort using a system consisting of a computer, monitor, and a mouse.

Inclusion Criteria:

• male or female patient 50 years of age or older; diagnosis of COPD; current or ex-smoker with at least 10 pack-years of smoking; a patient-reported score for breathlessness during activities of daily living of < 9 on the self-administered computerized baseline dyspnea index; a post-bronchodilator FEV1 < 80% predicted; a post-bronchodilator FEV1/FVC ratio < 70%; and clinically stable condition.

Exclusion Criteria:

• any concomitant disease that interferes with study procedures or evaluation; inability to exercise on the treadmill or cycle ergometer; inability to withhold short-acting bronchodilators for 4 hours or long-acting bronchodilators for 12 hrs (salmeterol or formoterol) and for 24 hours (tiotropium) prior to testing

Study completed with no reported adverse effects. One limitation of the study is frequent exercise tests involving 7 visits for each participant