Adaptation to life in the high andes: Nocturnal oxyhemoglobin saturation in early development

Catherine Mary Hill*, Ana Baya, Johanna Gavlak, Annette Carroll, Kate Heathcote, Dagmara Dimitriou, Veline L'Esperance, Rebecca Webster, John Holloway, Javier Virues-Ortega, Fenella Jane Kirkham, Romola Starr Bucks, Alexandra Marie Hogan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Study Objectives: Physiological adaptation to high altitude hypoxia may be impaired in Andeans with significant European ancestry. The respiratory eburden f of sleep may challenge adaptation, leading to relative nocturnal hypoxia. Developmental aspects of sleep-related breathing in high-altitude native children have not previously been reported. We aimed to determine the influence of development on diurnal-nocturnal oxyhemoglobin differences in children living at high altitude. Methods: This was a cross-sectional, observational study. Seventy-five healthy Bolivian children aged 6 mo to 17 y, native to low altitude (500 m), moderate high altitude (2,500 m), and high altitude (3,700 m) were recruited. Daytime resting pulse oximetry was compared to overnight recordings using Masimo radical oximeters. Genetic ancestry was determined from DNA samples. Results: Children had mixed European/Amerindian ancestry, with no significant differences between altitudes. Sixty-two participants had . 5 h of nocturnal, artifact-free data. As predicted, diurnal mean oxyhemoglobin saturation decreased across altitudes (infants and children, both P < 0.001), with lowest diurnal values at high altitude in infants. At high altitude, there was a greater drop in nocturnal mean oxyhemoglobin saturation (infants, P < 0.001; children, P = 0.039) and an increase in variability (all P . 0.001) compared to low altitude. Importantly, diurnal to nocturnal altitude differences diminished (P = 0.036), from infancy to childhood, with no further change during adolescence. Conclusions: Physiological adaptation to high-altitude living in native Andeans is unlikely to compensate for the significant differences we observed between diurnal and nocturnal oxyhemoglobin saturation, most marked in infancy. This vulnerability to sleep-related hypoxia in early childhood has potential lifespan implications. Future studies should characterize the sleep- related respiratory physiology underpinning our observations.

Original languageEnglish
Pages (from-to)1001-1008
Number of pages8
Issue number5
Publication statusPublished - 1 May 2016


  • Altitude
  • Central apnea
  • Intermittent hypoxia
  • Respiratory control
  • Sleep disordered breathing


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