ACUTE MOUNTAIN-SICKNESS AND VENTILATORY F UNCTION IN SUBJECTS INTERMITTENTLY EXPOSED TO HYPOBARIC HYPOXIA

Aiming to assess the magnitude of acute mountain sickness symptoms and ventilatory function in subjects intermittently exposed to hypobaric hypoxia, we studied 48 healthy men aged 32.6 +/- 8.2 years old who wor ked in a gold mine at a altitude of 4600 m, using a shedule of 8-12 da ys of work at the mine followed by 4 days of rest at the sea level. St udies were performed at the sea level (A), during the first two days o f ascension (B) and after three or four days of stay at 4600 m (C). Mo untain sickness symtoms were evaluated with a questionnaire devised in the 1991 International Hypoxia Symposium and respiratory function was assessed with a Collins Eagle II respirometer, following American Tho racic Society recommendations. Subjects reported mild to moderate symp toms during the first 24 hours of ascending (mean scor of 6.4 +/- 3.1 for a maximum of 15). Forced vital capacity fell significantly in peri od B and returned to normal in period C and forced expiratory volume i n 1 s did not change in any period. However, maximal expiratory flow a nd maximal midexpiratory flow rate significantly increased and remaine d elevated during the four days stay at the mine. No correlation was f ound between acute mountain sickness symptoms and changes in ventilato ry function.