Exercise capacity can be directly measured in the
clinic. A number of drugs that improve airflow have
been shown to increase exercise capacity in COPD,
though effect sizes vary between trials. Various types
of exercise training also increase exercise capacity. One mechanism through which exercise training
improves exercise capacity is by improving skeletal
muscle function; this occurs when training intensity
is high enough to provide an overload stimulus on the
skeletal muscle. The combination of pulmonary
rehabilitation with bronchodilator therapy increases
exercise capacity to a greater extent than either component
alone, and guidelines recommend that optimal
bronchodilator therapy should be given prior to exercise
training to enhance performance in and outside the
training programme.