Bronchial Asthma and Airway Hyperresponsiveness at High Altitude

Abstract

The mountain climate can modify respiratory function and bronchial responsiveness of asthmatic subjects. Hypoxia, hyperventilation of cold and dry air and physical exertion may worsen asthma or enhance bronchial hyperresponsiveness while a reduction in pollen and pollution may play an important role in reducing bronchial inflammation. At moderate altitude (1,500-2,500 m), the main effect is the absence of allergen and pollutants. We studied bronchial hyperresponsiveness to both hyposmolar aerosol and methacholine at sea level (SL) and at high altitude (HA; 5,050 m) in 11 adult subjects (23-48 years old, 8 atopic, 3 nonatopic) affected by mild asthma. Basal FEV₁ at SL and HA were not different (p = 0.09), whereas the decrease in FEV₁ induced by the challenge was significantly higher at SL than at HA. (1) Hyposmolar aerosol: at SL the mean FEV₁ decreased by 28% from 4.32 to 3.11 liters; at 5,050 m by 7.2% from 4.41 to 4.1 liters (p < 0.001). (2) Methacholine challenge: at SL PD20-FEV₁ was 700 μg and at HA > 1,600 μg (p < 0.005). In 3 asthmatic and 5 nonasthmatic subjects plasma levels of cortisol were also measured. The mean value at SL was 265 nmol and 601 nmol at HA (p < 0.005). We suppose that the reduction in bronchial response might be mainly related to the protective role carried out by the higher levels of cortisol and, as already known, catecholamines.

Travel to high altitude with pre-existing lung disease

“…One problem with this study, however, was the fact that all subjects received either dexamethasone or acetazolamide at the highest elevation, which might have affected bronchial hyperreactivity. COGO et al [147] reached a different conclusion than LOUIE and PARE [146]. They studied 11 mild asthmatic patients at sea level and 5,050 m and demonstrated decreased bronchial reactivity to both hypoosmolar aerosol and methacholine at high altitude.…”

High-altitude alpine therapy and lung function in asthma: Systematic review and meta-analysis

“…The remaining 35 studies underwent further review. Critical review of complete texts of the 35 eligible studies identified two publications [9,10] that were excluded because they were based on data ultimately subsumed in two other publications [11,12]. We also found that a study set of one publication [13] was included within a larger cohort [14], so only the latter was included.…”

High‐Altitude Climate Therapy Reduces Local Airway Inflammation and Modulates Lymphocyte Activation

“…Main factors that are suggested to influence asthma in high-altitude climate therapy are allergen avoidance, increased cortisol and catecholamine level, the dry air and high UV light exposure [15][16][17][18]. However, only little is known about the underlying immunological mechanisms [19,20].…”