Acute mountain sickness at 3500 and 4250 m. A study of symptom Incidence and severity

Background: Acute Mountain Sickness (AMS) refers to signs and symptoms asso ciated with hypoharic hypoxia. Its reported incidence is highly variable. A im: To determine the incidence of AMS symptoms and severity at 3,500 and 4, 250 m above sea level. Subjects and methods: A population of 362 soldiers w ithout former exposure to altitude was studied. AMS symptoms, were assessed by an extensively used standard questionnaire (Lake Louise), applied 36-72 hours after exposure to high altitude. Results: A group of 200 recruits as cended to Putre (3,500 m) and a second group (162) ascended to Alto Pacollo (4,250 m). The incidence of AMS was 28% and 60% respectively (p<0.05). Hea daches and sleeping difficulties were the most frequent symptoms at both al titudes. Furthermore, severe digestive problems and dizziness were describe d in a high proportion of individuals at both 3,500 and 4,250 m. Conclusion s: The prevalence of AMS in this study is similar to that reported elsewher e at equivalent altitudes.