Abstract
Introduction: Both the membrane (Dm) and the capillary (Vc) component of lung diffusing capacity (DL) have been shown to be increased in high altitude residents and to remain essentially unchanged in high altitude sojourners. Maximal exercise has been reported to decrease Dm at sea level (Manier 1993). The effects of high altitude exercise on Dm and Vc as evaluated from the DL for carbon monoxide (DLCO) and nitric oxide (DLNO) respectively, are incompletely understood.
Methods: Lowlanders (n=10) and highlanders (n=14) were tested at 4380m above sea level (Cerro de Pasco, Peru); lowlanders also underwent tests at sea level. Spirometry, alveolar volume (VA), DLCO, DLNO, Dm and Vc were assessed (Hypercompact Medisoft, Belgium) using the NO/CO transfer technique. Values were corrected for PcapO2, Hb and are presented as mean predicted value (Aguilaniu 2008) ±SEM. Measurements took place at rest and after an endurance test at 80% of VO2max at heart rate returned to rest values.
Results: Spirometry was normal in all subjects. Hb nor SaO2 at rest were significantly different between the groups.
At sea level, lowlanders did not demonstrate alterations in diffusion parameters pre- vs. post-endurance test.
Conclusion: Strenuous exercise in lowlanders resulted in a decrease of DLCO which was probably caused by interstitial lung edema thickening the alveolocapillary membrane, whereas highlanders were capable of maintaining DLCO-levels by an increase in Dm.
- © 2011 ERS