title: Women candidates for diving with oxygen-enriched gas mixtures have a lower end tidal CO2 than men during moderate exercise.
abstract: We have previously determined the thresholds for CO2 detection (conscious recognition of elevated CO2) and retention in male divers, beyond which a diving candidate should not continue his diving activity due to an increased risk of CNS oxygen toxicity. The purpose of the present study was to establish whether there is a difference in end tidal PCO2 between male and female divers who use oxygen-enriched gas mixtures. Ventilatory and perceptual responses to variations in inspired CO2 (range 0-42 mm Hg) were assessed during moderate exercise in 18 males and 18 females. End tidal PCO2 was lower in the female divers when breathing oxygen with 42 mm Hg CO2 (58.2±3.0 mm Hg vs. 61.5±4.5 mm Hg, P<0.03). These results suggest that female divers have a lower end tidal CO2 than males when breathing a hyperoxic gas mixture during exercise, which might imply that women are less susceptible to CNS oxygen toxicity than men.
authors.affiliation: Israel Naval Medical Institute, IDF Medical Corps, Haifa, Israel. Electronic address: estie@idf.gov.il.
authors.forename: Mirit
authors.initials: M
authors.lastname: Eynan
authors.forename: Amir
authors.initials: A
authors.lastname: Abramovich
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Arieli
mesh_terms: D000293:Adolescent; D002245:Carbon Dioxide / Q000378:metabolism*; D004242:Diving / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen; D010806:Physical Education and Training / Q000379:methods*; D012123:Pulmonary Ventilation / Q000502:physiology*; D012727:Sex Characteristics; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: Carbon dioxide detection; Carbon dioxide retention; Central nervous system oxygen toxicity; Ventilatory response; Women divers