IntroductionMountaineers exposed to hypobaric hypoxia (HH) show high-altitude periodic breathing (PB).ObjectiveTo analyze high-altitude PB during the ascent of Mount Aconcagua (Argentina).Materials and MethodsDescriptive study in healthy volunteers using respiratory polygraphy (RP) at different altitudes.ResultsWe studied 8 andinist, mean age: 36 years old (25-51), body mass index (BMI) of 23.6 (20.9-28.7) and 22.77 (20.9-27.7) upon return, p<0.01. RP without PB showed a lower Oxygen Desaturation Index (ODI) and a lower Apnea-Hypopnea-Index (AHI); 5.43 (0 - 20) versus 45.95 (2-122) p<0.001 and 3.9 (0-15.5) versus 44.35 (4-115) p<0.001. AHI increased with altitude at the expense of central apneas and hypopneas: p<0.05.ConclusionHigh-altitude PB is frequent above 2,581m.a.s.l. And it is characterized by short cycles. None of the mountaineers showed PB at baseline; however, high-altitude PB occurred in all subjects above 4,900 m.a.s.l

Introduction: Mountaineers exposed to hypobaric hypoxia (HH) show high-altitude periodic breathing (PB). Objective: To analyze high-altitude PB during the ascent of Mount Aconcagua (Argentina). Materials and Methods: Descriptive study in healthy volunteers using respiratory polygraphy (RP) at different altitudes. Results: We studied 8 andinist, mean age: 36 years old (25-51), body mass index (BMI) of 23.6 (20.9-28.7) and 22.77 (20.9-27.7) upon return, p<0.01. RP without PB showed a lower Oxygen Desaturation Index (ODI) and a lower Apnea-HypopneaIndex (AHI); 5.43 (0 -20) versus 45.95 (2-122) p<0.001 and 3.9 (0-15.5) versus 44.35 (4-115) p<0.001. AHI increased with altitude at the expense of central apneas and hypopneas: p<0.05. Conclusion: High-altitude PB is frequent above 2,581m.a.s.l. And it is characterized by short cycles. None of the mountaineers showed PB at baseline; however, high-altitude PB occurred in all subjects above 4,900 m.a.s.l