Effect of Bronchodilation on Cycle vs Treadmill Exercise Endurance Time in COPD

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.