Abstract
A group of 18 asthmatics were evaluated in preparation for an expedition to climb the Aconcagua mountain (6900m).
Patients were evaluated at different time points before expedition: screening visit, hypoxia chamber and cold air exposition (in an attempt to simulate conditions at extreme altitude) as well as before/after the expedition. During the hypoxia simulating experiment, patients stayed for 30 min in a chamber filled with 11% of oxygen followed by a maximal exercise test. During the cold air exposition, patients resided for 24 hours in an indoor ski resort (mean temperature of -8 °C).
All patients except one (score of 18/25) had an ACT well controlled asthma (ACT > 20). During one year of preparation, FeNO values significantly reduced (p=0.01) while lung function parameters remained stable. FEV1 and FeNO values were slightly but significantly lower (mean change in%pred FEV1 of 2.7%, p=0.01 and mean change in FeNO of 2.2 ppb, p=0.03) after a maximal exercise protocol under hypoxic conditions (FiO2=11%). A significant decrease in FEV1 was also observed after a 24h stay at -8 °C (mean change of 6.6%, p=0.009). This was accompanied by an increase in sputum neutrophils (13% pre versus 48.6% post, p<0.01) but was not associated with a change in FeNO levels (p=0.07).
During one year of preparation prior to climbing the Aconcagua mountain, there was an improvement in airway inflammation despite adequate asthma control at baseline. Exercising in hypoxic conditions (60 min, FiO2 11%) induced a minor decrease in FEV1 and FENO in asthmatics. Exposure of asthmatic patients to cold air for 24hr resulted in a larger decrease in FEV1, which was associated with a neutrophilic airway inflammation.
- © 2011 ERS