Attacking the disease spiral in chronic obstructive pulmonary disease: an update.
In chronic obstructive pulmonary disease (COPD) a pathophysiological cycle occurs such that locomotor muscle weakness and fatiguabilty exist, which in turn limit exercise performance both because of leg discomfort and also because anaerobic metabolism leads to lactic acid production. Since the lactic acid is buffered by bicarbonate there is consequent carbon dioxide (CO2) production. Patients with advanced COPD are flow limited and cannot excrete the CO2 by raising ventilation and thus these patients experience breathlessness which discourages exercise and, in turn, prompts further deconditioning. Structured exercise, termed pulmonary rehabilitation is at the core of reversing the cycle but novel strategies should be employed for patients with advanced disease and alternative therapeutic opportunities may soon be available to improve pulmonary mechanics.
National Heart and Lung Institute, Respiratory Biomedical Research Unit, Royal Brompton Hospital and Imperial College, London. m.polkey@rbht.nhs.uk
Michael I
MI
Polkey
John
J
Moxham
D018493:Cardiovascular Deconditioning / Q000502:physiology; D018450:Disease Progression; D005080:Exercise Test; D006801:Humans; D055435:Myostatin / Q000378:metabolism; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000534:rehabilitation; D052097:Quadriceps Muscle / Q000503:physiopathology; D015656:Respiratory Mechanics
D055435:Myostatin