Exercise capacity and breathing mechanics in patients with airflow limitation

T. G. Babb, J. R. Rodarte

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


To investigate the impact of expiratory airflow limitation on ventilation during exercise, we studied six control subjects with normal lung function (FEV1/FVC = 79 ± 6%) and eight patients with borderline-to-mild airflow limitation (FEV1/FVC = 68 ± 4%) during cycle ergometry. VO2, HR, and VE/MVV were not different between the control subjects or patients during maximal or submaximal exercise. In contrast, five of the eight patients achieved maximal expiratory flow over a large portion (37%) of their tidal volume (VT) during submaximal exercise, whereas none of the control subjects achieved maximal expiratory flow. To estimate the fraction of expiratory capacity used by the control subjects and the patients, we • calculated a mechanical ventilatory maximum (VEmaxCal) for each level of exercise using the individual’s VT, end-expiratory lung volume (EELV), and maximal expiratory flow-volume curve. The patients used a greater fraction of their VEmaxCal at each level of submaximal exercise (P < 0.03). Despite the flow limitation during submaximal exercise, EELV was similar between the control subjects and patients. In conclusion, even patients with borderline-to-mild airflow limitation achieve maximal expiratory flow during submaximal exercise and these restrictions are not reflected by VE/MVV nor by EELV.

Original languageEnglish (US)
Pages (from-to)967-974
Number of pages8
JournalMedicine and science in sports and exercise
Issue number9
StatePublished - Feb 1992


  • Breathing
  • Copd
  • Lung mechanics
  • Lung volumes
  • Maximal ventilation
  • Pattern

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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