Impact of obesity on exercise performance and pulmonary rehabilitation

Authors


  • The Authors: Michael Dreher, MD is a senior respiratory physician at the Department of Pneumology, University Hospital Freiburg, Germany. His research focuses on several aspects of mechanical ventilation including its effects at rest and during exercise, and the process of weaning from mechanical ventilation. Hans-Joachim Kabitz, MD works as respiratory specialist in the Department of Pneumology, at the University Hospital Freiburg, Germany, where he also heads the Respiratory Physiology Research Group. His research focuses on the evaluation of respiratory muscle function and fatigue both at rest and during exercise.

  • SERIES EDITOR: AMANDA J PIPER

Michael Dreher, Department of Pneumology, University Hospital Freiburg, Killianstrasse 5, D—79106 Freiburg, Germany. Email: michael.dreher@uniklinik-freiburg.de

ABSTRACT

While the impact of obesity on respiratory function has been extensively studied, and several definitive conclusions have emerged, its impact on exercise performance is complex, with the available data sometimes providing contradictory or inconclusive information.

Based on the literature discussed, it appears that resting alterations in lung volumes and gas exchange become attenuated during exercise in the obese, while oxygen cost of breathing and dyspnoea are increased. Respiratory muscle function also seems to be impaired, such that inspiratory muscle strength is reduced and respiratory drive is increased. Furthermore, while there is no reduction in the absolute values of maximal oxygen uptake compared with normal-weight subjects, oxygen uptake at a given workload is increased and maximal workload is reduced in the obese, caused by increases in body mass and/or basal metabolic rate. To date, obesity has not been listed as an indication for pulmonary rehabilitation (PR), hence the reason why conclusive data on the impact of obesity per se on PR are lacking. The majority of evidence discussed is based on comparative data from obese versus normal-weight patients, with respiratory disorders currently established as indications for PR. The best evidence currently available regarding the impact of obesity on PR is for patients with chronic obstructive pulmonary disease (COPD); here, it appears that obesity per se has no negative impact on PR. Otherwise, there are no conclusive data on the impact of obesity on PR in respiratory disorders other than COPD, and this remains to be investigated in the future.

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