Medicine and science in sports and exercise
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Med Sci Sports Exerc · Jul 2001
ReviewVentilatory limitations in chronic obstructive pulmonary disease.
Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder characterized by dysfunction of the small and large airways, as well as by destruction of the lung parenchyma and vasculature, in highly variable combinations. Breathlessness and exercise intolerance are the most common symptoms in COPD and progress relentlessly as the disease advances. Exercise intolerance is multifactorial, but in more severe disease, ventilatory limitation is often the proximate exercise-limiting event. ⋯ DH compromises the ability of the inspiratory muscles to generate pressure, and the positive intrathoracic pressures likely contribute to cardiac impairment during exercise. Progressive DH hastens the development of critical ventilatory constraints that limit exercise and, by causing serious neuromechanical uncoupling, contributes importantly to the quality and intensity of breathlessness. The corollary of this is that therapeutic interventions that reduce operational lung volumes during exercise, by improving lung emptying or by reducing ventilatory demand (which delays the rate of DH), result in clinically meaningful improvement of exercise endurance and symptoms in disabled COPD patients.