title: Cardiovascular and ventilatory responses to dorsal, facial, and whole-head water immersion in eupnea.
abstract: OBJECTIVE
  Facial cooling can regulate reflexes of the dive response whereas further body cooling generally induces the cold-shock response. We examined the cardiovascular and ventilatory parameters of these responses during 3-min immersions of the head dorsum, face, and whole head in 17 degrees C water while breathing was maintained.
  
  
  METHODS
  From a horizontal position, the head was inserted into a temperature controlled immersion tank in which the water level could be changed rapidly. On four occasions, either the head dorsum, face or whole head (prone and supine) were exposed to water.
  
  
  RESULTS
  Mean decrease in heart rate (14%) and increases in systolic (9%) and diastolic (5%) blood pressures were seen during immersion. Relative mean finger skin blood flow had an early transient decrease (31%) for 90 s and then returned to baseline values. A strong transient increase was seen in minute ventilation (92%) at 20 s of immersion via tidal volume (85%). There were no consistent differences between the head dorsum, face, and whole head for all variables in response to immersion.
  
  
  CONCLUSIONS
  The cold-shock response (increased minute ventilation and tidal volume) predominated over the dive response in the initial moments of immersion only. The order of emergence of these responses provides further recommendation to avoid head submersion upon cold water entry. It is important to protect the face, with a facemask, and the head dorsum, with an insulative hood, in cold water.
authors.affiliation: Laboratory for Exercise and Environmental Medicine, Health, Leisure and Human Performance Research Institute, University of Manitoba, Winnipeg, Canada.
authors.forename: Dominique D
authors.initials: DD
authors.lastname: Gagnon
authors.forename: Thea
authors.initials: T
authors.lastname: Pretorius
authors.forename: Gerren
authors.initials: G
authors.lastname: McDonald
authors.forename: Glen P
authors.initials: GP
authors.lastname: Kenny
authors.forename: Gordon G
authors.initials: GG
authors.lastname: Giesbrecht
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure; D003080:Cold Temperature; D058639:Cold-Shock Response; D004242:Diving / Q000502:physiology*; D005145:Face; D005385:Fingers / Q000098:blood supply; D006257:Head; D006339:Heart Rate; D006801:Humans; D007101:Immersion; D008297:Male; D012039:Regional Blood Flow; D013990:Tidal Volume; D013997:Time Factors; D014867:Water
chemical_list: D014867:Water