Julian, Colleen Glyde2026-03-222026-03-222013https://andeanlibrary.org/handle/123456789/6999Abstract. Chronic mountain sickness (CMS) is considered to be a loss of ventilatory acclimatization to high altitude (>2500 m) resulting in marked arterial hypoxemia and polycythemia. This case-control study explores the possibility that sleep-disordered breathing (SBD) and associated oxidative stress contribute to the etiology of CMS. Nocturnal respiratory and SaO2 patterns were measured using standard polysomnography techniques and compared between male high-altitude residents (aged 18–25) with preclinical CMS ([excessive erythrocytosis (EE)], n=20) and controls (n=19). Measures of oxidative stress and antioxidant status included isoprostanes (8-iso-PGF2 alpha), superoxide dismutase and ascorbic acid. EE cases had a greater apnea-hypopnea index, a higher frequency of apneas (central and obstructive) and hypopneas during REM sleep, and lower nocturnal SaO2 compared to controls. 8-iso-PGF2alpha was greater in EE than controls, negatively associated with nocturnal SaO2, and positively associated with hemoglobin concentration. Mild sleep-disordered breathing and oxidative stress are evident in preclinical CMS, suggesting that the resolution of nocturnal hypoxemia or antioxidant treatment may prevent disease progression.enALTURAESTRÉS OXIDATIVOPOLICITEMIAArticle