**1. Introduction**

Chronic obstructive pulmonary disease (COPD) is among the five leading causes of death in developed world [1]. Prevalence of COPD is constantly increasing. COPD has a high impact on patients' wellbeing, healthcare utilization, and mortality [2] and causes a substantial and increasing economic and social burden [3, 4]. Cigarette smoking is clearly the predominant cause but other environmental agents including biomass fuel and air pollution may play a role as well. Common symptoms of COPD patients are chronic and progressive dyspnea, cough, and sputum production. These symptoms can be disabling and lead to activity limitation and ultimately inability to work and take care of themselves [5]. This vicious circle of inactivity that begins with breathlessness is because of peripheral muscle dysfunction [6], and dynamic hyperinflation [7].

For several decades, treatment of COPD has been focused on smoking cessation, and pharmacological but with ever-increasing literature, intense exercise programs like pulmonary rehabilitation (PR) have become an integral part of management of COPD [8]. PR has been shown to be the most effective non-pharmacological intervention for improving health status in COPD patients and has become a standard of care for these patients [2]. PR and pharmacological therapy are not competitive but rather, must work closely together, if they are to result in a more successful outcome [9].

Despite increasing awareness on positive impact of rehabilitation in COPD, it remains underutilized in most countries. Lack of understanding on the benefits of a PR program, in addition to the incremental cost to the management, has hindered the widespread adoption of comprehensive PR for COPD patients [9]. This chapter aims at highlighting the impact of PR on patients with COPD, focusing on the clinical usefulness of PR. We also hope to stimulate primary care and pulmonary physicians to use PR more often.
