title: Carbohydrate and fluid intake affect the saliva flow rate and IgA response to cycling.
abstract: OBJECTIVE
  The purpose of this study was to examine the effect of regular CHO beverage ingestion and restricted fluid intake on various salivary parameters during prolonged cycle exercise.
  
  
  METHODS
  In a randomized block design, 15 recreationally active men cycled for 2 h at 60% VO2max on three occasions, separated by 1 wk. On the CHO and placebo (PLA) treatments, subjects consumed either a glucose (60 g x L(-1)) or placebo drink before (400 mL), during (150 mL every 15 min), and after (400 mL) the exercise. On the restricted fluid intake (RFI) treatment subjects were given a total of 200 mL of placebo fluid to take as desired every 15-min during the exercise. Timed, unstimulated saliva samples were collected preexercise, at 1, 1.5, and 2 h of exercise and at 1 h postexercise. Blood samples were obtained from a subset of 8 subjects preexercise, postexercise, and at 1 h postexercise.
  
  
  RESULTS
  Postexercise plasma glucose levels were 18% and 20% lower on the PLA and RFI treatments, respectively, compared with the CHO treatment (P < 0.01). Saliva flow rates were significantly higher on the CHO treatment compared with the RFI treatment at 1.5 h and 2 h of exercise (P < 0.01 and P < 0.05, respectively). Salivary IgA (s-IgA) concentration was significantly lower on the CHO treatment compared with the RFI treatment throughout the exercise (P < 0.05). No other differences were seen between treatments for either saliva flow rate or s-IgA concentration. Neither s-IgA secretion rate, alpha-amylase activity, nor alpha-amylase secretion rate were affected by treatment.
  
  
  CONCLUSIONS
  These findings suggest that CHO and fluid intake influence the s-IgA and saliva flow rate response to prolonged submaximal exercise.
authors: School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, England.
authors: N C
authors: NC
authors: Bishop
authors: A K
authors: AK
authors: Blannin
authors: E
authors: E
authors: Armstrong
authors: M
authors: M
authors: Rickman
authors: M
authors: M
authors: Gleeson
mesh_terms: D000328:Adult; D001628:Beverages; D001642:Bicycling / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D008297:Male; D012463:Saliva / Q000737:chemistry*; D012472:Salivation / Q000187:drug effects / Q000502:physiology*; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D007070:Immunoglobulin A; D000516:alpha-Amylases