Carbon monoxide exposure from cooking in snow caves at high altitude

L. E. Keyes, R. S. Hamilton, J. S. Rose

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Objective. To determine the physiological consequences of acute CO exposure from cooking in snow caves at 3200 m. We hypothesized that ambient CO and serum carboxyhemoglobin (COHb) levels would increase and that even low levels of COHb would be associated with symptoms of CO poisoning at high altitude. Method. This was a prospective observational study. Twenty-two healthy volunteers age 18 years or older were recruited during a winter camping trip at 3200 m. Subjects filled out symptom questionnaires, and heart rate (HR), oxygen saturation (SaO2), serum COHb, and ambient CO were all measured before and after cooking inside snow caves. Results. Median age of subjects was 32 years, and 87% were male. The median ambient CO level increased by 17 ppm (IQR, 2-27 ppm), P = .005. Mean serum COHb level rose from 0.3% (IQR, 0.2%-0.4%) to 1.2% (IQR, 0.7%-2.6%) after cooking, for a difference of 1% (IQR, 0.4%-2.3%), P < .001. There were no differences in symptom scores before and after cooking, and there was no significant effect on HR or SaO2. Conclusion. A single exposure to CO at 3200 m increases ambient CO and COHb but not to clinically important levels. Further studies are needed to examine the risks of longer exposures at higher altitudes.

Original languageEnglish (US)
Pages (from-to)208-212
Number of pages5
JournalWilderness and Environmental Medicine
Issue number3
StatePublished - 2001


  • Air pollutants
  • Carbon monoxide
  • Carboxyhemoglobin
  • Environmental exposure
  • Heating
  • High altitude
  • Mountaineering

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Orthopedics and Sports Medicine


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