title: Salivary IgA response to prolonged exercise in a cold environment in trained cyclists.
abstract: OBJECTIVE
  The purpose of the present study was to determine the effect of a prolonged bout of exercise in freezing cold conditions on saliva immunoglobulin A (s-IgA) responses in endurance-trained males.
  
  
  METHODS
  Using a randomized cross-over design, 15 trained male cyclists cycled for 2 h on a stationary ergometer at 70% VO(2max) in an environmental chamber on one occasion at a temperature of -6.4 +/- 0.1 degrees C (cold) and on another occasion at a temperature of 19.8 +/- 0.2 degrees C (control). Trials began at 12:30 h to avoid the fall in s-IgA concentration that occurs during the morning hours. Unstimulated whole-saliva samples were collected over a 2-min period at preexercise, postexercise, and 2-h postexercise. The s-IgA concentration was determined using a sandwich-type ELISA method.
  
  
  RESULTS
  Saliva flow rate decreased postexercise by 31%, returning to preexercise levels by the 2-h postexercise collection (main effect of time: < 0.01). The decrease in saliva flow rate postexercise in the control trial (39% compared with 22% on cold trial) approached significance (interaction: = 0.08) and may have accounted for the corresponding increase in s-IgA concentration postexercise in the control trial (s-IgA concentration: control preexercise; 91 +/- 12; postexercise; 110 +/- 13 mg x L(-1); < 0.05). Saliva IgA secretion rate decreased postexercise by 19.5% returning to preexercise levels by 2-h postexercise measure (main effect of time: < 0.05).
  
  
  CONCLUSIONS
  These data show that performing a bout of prolonged exercise results in a reduction in s-IgA secretion rate. Additionally, these data demonstrate that performing prolonged exercise in freezing cold conditions does not influence saliva flow rate or s-IgA secretion rate responses to prolonged exercise.
authors.affiliation: School of Sport, Health and Excercise Sciences, University of Wales, Bangor, United Kingdom. n.walsh@bangor.ac.uk
authors.forename: Neil P
authors.initials: NP
authors.lastname: Walsh
authors.forename: Nicolette C
authors.initials: NC
authors.lastname: Bishop
authors.forename: James
authors.initials: J
authors.lastname: Blackwell
authors.forename: Simon G
authors.initials: SG
authors.lastname: Wierzbicki
authors.forename: Joanna C
authors.initials: JC
authors.lastname: Montague
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002940:Circadian Rhythm; D003080:Cold Temperature; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis / Q000378:metabolism*; D008297:Male; D012463:Saliva / Q000737:chemistry / Q000378:metabolism*; D012472:Salivation / Q000502:physiology; D013997:Time Factors
chemical_list: D007070:Immunoglobulin A