Effects of Bronchodilators in Mild Chronic Obstructive Pulmonary Disease (COPD)
Effects of Bronchodilators in Mild Chronic Obstructive Pulmonary Disease (COPD)
In people with mild COPD, the ability to exhale air from the lungs is partly limited because
 of narrowing and collapse of the airways. This results in the trapping of air within the
 lungs and over-distention of the lungs and chest (lung hyperinflation).

 Breathing at high lung volumes (hyperinflation) is an important cause of breathing discomfort
 (dyspnea) in people with COPD. Bronchodilators help to relax muscles in the airways or
 breathing tubes. Bronchodilators are often prescribed if a cough occurs with airway narrowing
 as this medication can reduce coughing, wheezing and shortness of breath. Bronchodilators can
 be taken orally, through injection or through inhalation and begin to act almost immediately
 but with the effect only lasting 4-6 hours. The main purpose of this study is to examine the
 effects of inhaled bronchodilators on breathing discomfort and exercise endurance in patients
 with mild COPD.
In people with mild COPD, the ability to exhale air from the lungs is partly limited because
 of narrowing and collapse of the airways. This results in the trapping of air within the
 lungs and over-distention of the lungs and chest - this is known as lung hyperinflation. We
 believe that breathing at high lung volumes (hyperinflation) is an important cause of
 breathing discomfort (dyspnea) in people with COPD. Bronchodilators help to relax muscles in
 the airways or breathing tubes. Bronchodilators are often prescribed if a cough occurs with
 airway narrowing; this medication can reduce coughing, wheezing and shortness of breath.
 Bronchodilators can be taken orally, through injection or through inhalation and begin to act
 almost immediately but with the effect only lasting 4-6 hours. The main purpose of this study
 is to examine the effects of inhaled bronchodilators on breathing discomfort and exercise
 endurance in patients with mild COPD.

 Each subject will attend 4 visits to the laboratory. Visit 1 (screening visit) will involve a
 record of medical history, medications used, anthropometrics measurements, questionnaires,
 breathing tests, an incremental cycle exercise test and a constant-workload cycle exercise
 test. Visit 2 will involve breathing tests and a constant-workload cycle exercise test.
 Visits 3 and 4 will involve breathing tests and a constant-workload cycle exercise test after
 subjects have been randomized to either placebo or Atrovent. These visits will be done on
 separate days and subjects will receive the two above treatments in random order.
Inclusion Criteria:

 -  diagnosis of mild COPD OR healthy control subjects

 -  40-80 years old

 -  able to perform all study procedures

 -  Smoking history > 10 pack years (for mild COPD) or smoking history < 10 pack years
 (for healthy control subjects)

 Exclusion Criteria:

 -  allergy to atrovent

 -  history of asthma, atopy or nasal polyps

 -  Oxygen desaturation < 80 % during exercise

 -  recent history of CAD (under a year) or any significant diseases that could contribute
 to dyspnea or exercise limitation