title: Extended observation of the nasal cycle using a portable rhinoflowmeter.
abstract: OBJECTIVE
  Nasal patency varies owing to the effects of humidity, temperature, and exercise. In addition, periodic cycles of congestion and decongestion that alternate between the right and the left side of the nose, which are termed the "nasal cycle," have been observed. The physiologic mechanisms underlying this cycle are not clear. Sympathetic nerves that supply the nose are regulated by the hypothalamus and the vasomotor areas of the brainstem. It is possible that the nasal cycle could be involved in protection against respiratory infection or allergies. Conventional methods of studying the nasal cycle, including rhinomanometry and acoustic rhinometry, impose limitations on the location and timing of evaluation. We studied the nasal cycle using a new portable device for relatively long-term rhinoflowmetry.
  
  
  METHODS
  Twenty normal subjects aged 24 to 77 years were fitted with the portable rhinoflowmeter (Rhinocycle, Rhinometrics, Lynge, Denmark) to continuously measure nasal air flow via each nostril over 12 daytime hours.
  
  
  RESULTS
  No subject complained of discomfort owing to the device, and 14 of them showed a detectable nasal cycle. The mean nasal cycle duration was 110 minutes, although variation was considerable, even in a single subject.
  
  
  CONCLUSIONS
  The portable device proved useful for observing the nasal cycle, and it should be valuable for the general investigation of nasal physiology.
authors.affiliation: Department of Otorhinolaryngology, Ohashi Hospital, Toho University, Tokyo, Japan. mtohki@med.toho-u.ac.jp
authors.forename: Motofumi
authors.initials: M
authors.lastname: Ohki
authors.forename: Toshio
authors.initials: T
authors.lastname: Ogoshi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yuasa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kawano
authors.forename: Madoka
authors.initials: M
authors.lastname: Kawano
mesh_terms: D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology*; D015444:Exercise; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000502:physiology*; D015508:Nasal Obstruction / Q000503:physiopathology*; D012123:Pulmonary Ventilation / Q000502:physiology*; D012212:Rheology / Q000295:instrumentation*; D013696:Temperature