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. © 1997 S. Karger AG, Basel.
Bronchial asthma and airway hyperresponsiveness at high altitude
COGO, Annaluisa;
1997
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. © 1997 S. Karger AG, Basel.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
