title: [Is olfactory function impaired in moderate height?].
abstract: BACKGROUND
  The human sense of smell seems to be influenced by the surrounding barometric pressure. These factors appear to be especially important during flights, for example, in order to recognize the smell of fire etc. Thus, questions are whether pilots or passengers exhibit an impaired smell sensitivity when tested at moderate heights, or, whether changes in humidity would affect the sense of smell.
  
  
  METHODS
  Using climate chambers, odor discrimination and butanol odor thresholds were tested in 77 healthy normosmic volunteers (5 female, 72 male; aged 25+/-8 years from 18 up to 53 years) under hypobaric (2 700+/-20 m, 20 degrees C+/-1 K, rh=50+/-5%) and hyperbaric, (10+/-0.5 m (2 bar)) and different humidity conditions (30 vs. 80%, 20 degrees C+/-1 K, normobaric). During all conditions cognitive performance was tested.
  
  
  RESULTS
  Among other effects, olfactory sensitivity was impaired at threshold, but not suprathreshold level, in a hypobaric compared to a hyperbaric milieu, and thresholds were lower in humid, compared to relatively dry conditions.
  
  
  CONCLUSIONS
  In conclusion, environmental conditions modulate the sense of smell, and may, consecutively, influence results from olfactory tests. During flight hypobaric conditions, mild hypoxia and dry air may cause impaired sensitivity of smell.
authors.affiliation: Flugmedizinisches Institut der Luftwaffe, Abteilung Flugphysiologie, Königsbrück.
authors.forename: M
authors.initials: M
authors.lastname: Kühn
authors.forename: H
authors.initials: H
authors.lastname: Welsch
authors.forename: T
authors.initials: T
authors.lastname: Zahnert
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
mesh_terms: D000293:Adolescent; D000328:Adult; D000401:Aircraft; D000531:Altitude; D001274:Atmospheric Pressure; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D012684:Sensory Thresholds / Q000502:physiology; D012903:Smell / Q000502:physiology*; D055815:Young Adult