Exercise and activity limitation are characteristic features of chronic obstructive pulmonary disease (COPD). Exercise intolerance may result from ventilatory limitation, cardiovascular impairment, and/or skeletal muscle dysfunction. Exercise training, a core component of pulmonary rehabilitation, improves the exercise capacity (endurance and, to a lesser degree, maximal work capacity) of patients with COPD in spite of the irreversible abnormalities in lung function. Dyspnea and health-related quality of life also improve following pulmonary rehabilitation. The clinical benefits of exercise rehabilitation last up to 2 years following 8 to 12 weeks of training. Existing evidence-based guidelines recommend that exercise training/pulmonary rehabilitation be included routinely in the management of patients with moderate to severe COPD. Exercise training/ pulmonary rehabilitation may be undertaken in an inpatient, outpatient, or home-based setting, depending on the individual needs of the patient and available resources. The type and intensity of training and muscle groups trained determine the expected outcomes of exercise training. Both high- and low-intensity exercise lead to increased exercise endurance, but only high-intensity training also leads to physiologic gains in aerobic fitness. The rationale for and outcomes of lower- and upper-limb training, as well as ventilatory muscle training, are reviewed, and the potential for anabolic hormone supplementation to optimize the benefits of exercise training is discussed.