This study was designed to test the following hypothesis:

The acute changes in exercise tolerance during the endurance shuttle walk will be greater with salmeterol compared to placebo in patients with chronic obstructive pulmonary disease.

Background: Little is known about the responsiveness of the endurance shuttle walking test (ESWT) to pharmacotherapy in patients with chronic obstructive pulmonary disease (COPD). This exercise testing modality needs to be further investigated because of its relevance for activity of daily living.

Objective: To evaluate, in patients with COPD, the responsiveness of the ESWT to detect improvement in walking performance after single dose of salmeterol.

Methods: In a randomised, double-blind, placebo-controlled, crossover study, 20 patients with COPD will perform, on two separate days, an ESWT at 80% of peak capacity, 2 hours after inhaling either a placebo or 50µg of salmeterol. Cardiorespiratory parameters will be monitored breath-by-breath during each walking test with a portable telemetric gas analyzer (Oxycom Mobile, Jaeger, Germany). Inspiratory capacities and Borg ratings for dyspnea were obtained every other minute throughout the tests.

Planned analysis. The main outcome will be endurance time. This variable will be compared between the two treatment arms using a paired t test. The time course of the cardiorespiratory parameters and dyspnea over time will be compared between the two exercise modalities. Comparisons will be done using a repeated measure design (ANOVA). Significance level will be set at a p value of 0.05.

Inclusion Criteria:

• age > 50 years
• smoking history > 10 packs/year
• FEV1 < 70% of predicted and FEV1/FVC < 70%.

Exclusion Criteria:

• respiratory exacerbation within the 2 months preceding the study
• history of asthma
• significant O2 desaturation (SaO2 < 85%) at rest or during exercise
• presence of another pathology that could influence exercise tolerance.