Endurance exercise performance in acute hypoxia is influenced by expiratory flow limitation

Joshua C. Weavil, Joseph W. Duke, Jonathon L. Stickford, Joel M. Stager, Robert F. Chapman, Timothy D. Mickleborough

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Purpose: We sought to determine if expiratory flow limitation influences intensive aerobic exercise performance in mild hypoxia. Methods: Fourteen trained male cyclists were separated into flow-limited (FL, n = 7) and non-FL (n = 7) groups based on the extent of expiratory flow limitation exhibited during maximal exercise in normoxia. Participants performed two self-paced 5-km cycling time trials, one in normoxic (FIO2 = 0.21) and one in mild hypoxic (FIO2 = 0.17) conditions in a randomized, balanced order with the subjects blinded to composition of the inspirate. Percent change from normoxia to hypoxia in average power output (%ΔPTT) and time to completion (%ΔTTT) were used to assess performance. Results: Hypoxia resulted in a significant decline in estimated arterial O2 saturation and decrements in performance in both groups, although FL had a significantly smaller %ΔPTT (−4.0 ± 0.5 vs. −9.0 ± 1.8 %) and %ΔTTT (1.3 ± 0.3 vs. 3.7 ± 0.9 %) compared to non-FL. At the 5th km of the time trial, minute ventilation did not change from normoxia to hypoxia in FL (3.4 ± 3.1 %) or non-FL (2.3 ± 3.7 %), but only the non-FL reported a significantly increased dyspnea rating in hypoxia compared to normoxia (~9 %). Non-FL athletes did not utilize their ventilatory reserve to defend arterial oxygen saturation in hypoxia, which may have been due to an increased measure of dyspnea in the hypoxic trial. Conclusion: FL athletes experience less hypoxia-related aerobic exercise performance impairment as compared to non-FL athletes, despite having less ventilatory reserve.

Original languageEnglish (US)
Pages (from-to)1653-1663
Number of pages11
JournalEuropean Journal of Applied Physiology
Issue number8
StatePublished - Aug 25 2015
Externally publishedYes


  • Arterial
  • Dyspnea
  • Oxygen saturation
  • Time trial
  • Ventilation

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)


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