Exercise intolerance is an important problem for individuals with
COPD, often leading to a sedentary lifestyle and a downward spiral
of further deconditioning and disability (Casaburi 1993). Exercise
limitation in individuals with COPD has been attributed
to a reduction in ventilatory capacity (expiratory airflow limitation
and decreased elastic recoil causing lung hyperinflation)
and increased ventilatory requirements (ventilation to perfusion
mismatch) (Casaburi 1993; Wasserman 1993). Exercise training
for individuals with COPD decreases ventilatory requirements by
yielding more efficient exercise breathing patterns and lowering
ventilation, allowing for improved exercise tolerance (Casaburi
1997). Exercise training is an integral component of pulmonary
rehabilitation (PR), a multidisciplinary program of care that is
directed to persons with COPD and their families and is designed
to optimize physical and social performance and autonomy
(ATS 2004; Lacasse 2006). PR results in reduced dyspnoea, increased
exercise ability and improvement in both disease-specific
and generic health status (Chronic Respiratory Disease Questionnaire,
St. George’s Respiratory Questionnaire) (ATS 2004).