Use of beta-blockers has proven beneficial in patients with hypertension, heart failure, and in people who have suffered a heart attack. The use in patients who have Chronic Obstructive Pulmonary Disease (COPD) and reactive airway disease, however, has been limited due to possible side effects such as worsening of lung function or increasing airway spasms and asthma attacks. The purpose of this study is to find out if patients with COPD can tolerate being on a beta-blocker at doses recommended for the treatment of heart disease conditions. This study also seeks to find out if a selective beta-1 receptor beta-blocker is better than a non-selective beta-blocker in patients with mild to moderate COPD.