Pulmonary capillary reserve and exercise capacity at high altitude in healthy humans

Bryan J. Taylor, Kirsten E. Coffman, Douglas T. Summerfield, Amine N. Issa, Alex J. Kasak, Bruce D. Johnson

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Purpose: We determined whether well-acclimatized humans have a reserve to recruit pulmonary capillaries in response to exercise at high altitude. Methods: At sea level, lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary membrane conductance (DmCO), and pulmonary capillary blood volume (Vc) were measured at rest before maximal oxygen consumption ($$\dot{V}{\text{O}}_{2\hbox{max} }$$V˙O2max) was determined in seven adults. Then, DLCO, DmCO and Vc were measured pre- and post-exhaustive incremental exercise at 5150 m after ~40 days of acclimatization. Results: Immediately after exercise at high altitude, there was an increase in group mean DmCO (14 ± 10 %, P = 0.040) with no pre- to post-exercise change in group mean DLCO (46.9 ± 5.8 vs. 50.6 ± 9.6 ml/min/mmHg, P = 0.213) or Vc (151 ± 28 vs. 158 ± 37 ml, P = 0.693). There was, however, a ~20 % increase in DLCO from pre- to post-exercise at high altitude (51.2 ± 0.2 vs. 61.1 ± 0.2 ml/min/mmHg) with a concomitant increase in DmCO (123 ± 2 vs. 156 ± 4 ml/min/mmHg) and Vc (157 ± 3 vs. 180 ± 8 ml) in 2 of the 7 participants. There was a significant positive relationship between the decrease in $$\dot{V}{\text{O}}_{2\hbox{max} }$$V˙O2max from sea level to high altitude and the change in DLCO and lung diffusing capacity for nitric oxide (DLNO) from rest to end-exercise at high altitude. Conclusion: These data suggest that recruitment of the pulmonary capillaries in response to exercise at high altitude is limited in most well-acclimatized humans but that any such a reserve may be associated with better exercise capacity.

Original languageEnglish (US)
Pages (from-to)427-437
Number of pages11
JournalEuropean Journal of Applied Physiology
Issue number2
StatePublished - Feb 1 2016


  • Lung diffusing capacity
  • Maximal oxygen consumption
  • Pulmonary artery systolic pressure
  • Sea level

ASJC Scopus subject areas

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


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