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Respiratory function and the obesity paradox

Guenette, Jordan A; Jensen, Dennis; O'Donnell, Denis E

Current Opinion in Clinical Nutrition and Metabolic Care: November 2010 - Volume 13 - Issue 6 - p 618–624
doi: 10.1097/MCO.0b013e32833e3453
Nutrition and physiological function: Edited by Labros S. Sidossis and Annemie Schols

Purpose of review Obese individuals have impaired respiratory function relative to their normal-weight counterparts. Despite these negative effects, obesity is paradoxically associated with better survival in individuals with chronic obstructive pulmonary disease (COPD). The purpose of this review is to describe this ‘obesity paradox’, to discuss the effects of obesity on respiratory function, and to speculate as to whether obesity-related alterations in respiratory mechanics can influence the natural history of COPD.

Recent findings Given the known negative effects of obesity on respiratory physiology, it is reasonable to predict that obese COPD patients would be more likely to experience greater dyspnea and exercise intolerance relative to COPD patients of normal weight. However, recent evidence suggests that obese COPD patients have similar or better dyspnea scores during exercise and do not have diminished exercise capacity. These observations may be attributable to the fact that obese COPD patients have reduced operating lung volumes and higher inspiratory capacity to total lung capacity ratios than their lean COPD counterparts.

Summary Obese patients with COPD do not appear to be at a disadvantage during exercise relative to lean COPD patients. Obesity may be associated with improved survival in COPD but specific mechanisms for this paradox remain to be elucidated.

Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston General Hospital, Kingston, Ontario, Canada

Correspondence to Denis E. O'Donnell, MD, FRCP(I), FRCP(C), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, ON K7L-2V6, Canada Tel: +1 613 548 2339; e-mail: odonnell@queensu.ca

© 2010 Lippincott Williams & Wilkins, Inc.