Sleep respiratory disturbances during the ascent to Mount Aconcagua

Introduction: Mountaineers exposed to hypobaric hypoxia (HH) show high-altitude periodic breathing (PB) and its characteristics may vary during the ascent. Purpose: 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 between 746 meters above sea level (m.a.s.l) and 5.380 m.a.s.l. Results: 43 RP were conducted in 4 women and 4 men, mean age: 36 years old (25-51), with a baseline body mass index (BMI) of 23.6 kg/m2(20.9-28.7) and 22.77 kg/m2(20.9-27.7) upon return, p RP without PB showed a lower Oxygen Desaturation Index (ODI) 5.43 (0 – 20) versus 45.95 (2-122) p PB was not observed at 746 m.a.s.l. All mountaineers, however, showed high-altitude PB above 4.900 m.a.s.l. with mean altitude of 4.130 (2,581–5,380 m.a.s.l.), cycles of 24.2 seconds, and Duty Cycle of 0.417 (0.37-0.49) without variations at different altitudes. Conclusion: High-altitude PB is frequent above 2,581m.a.s.l. healthy volunteers and is characterized by short cycles and a stable Duty Cycle during the ascent.