title: Immunoendocrine response to cycling following ingestion of caffeine and carbohydrate.
abstract: OBJECTIVE
  This study investigated the effect of caffeine consumed with and without carbohydrate (CHO) on immunoendocrine responses after exercise.
  
  
  METHODS
  On four occasions, 12 recreational male cyclists cycled for 2 h at 65% V O2max. Sixty minutes before exercise, participants ingested 6 mg.kg(-1) body mass of caffeine (CAF) or placebo (PLA), then during exercise they consumed a 6% CHO or placebo (PLA) drink, providing CAF/CHO, PLA/CHO, CAF/PLA, and PLA/PLA conditions.
  
  
  RESULTS
  f-MLP-stimulated neutrophil oxidative burst responses were significantly higher after exercise on CAF/CHO and PLA/CHO (both P<0.05) than PLA/PLA when expressed as a percentage of baseline value. The response on CAF/PLA tended to be higher than PLA/PLA at this point (P=0.056). No significant differences between CAF/CHO, PLA/CHO, and CAF/PLA were observed after exercise; however, only PLA/CHO showed no significant postexercise decline. Coingestion of CAF/CHO significantly attenuated epinephrine (P<0.05) and IL-6 (P<0.05) responses that occurred after ingestion of CAF alone (CAF/PLA) and significantly attenuated the transient alterations in circulating leukocyte (P<0.05) and neutrophil (P<0.01) counts. Plasma cortisol concentration was significantly lower on PLA/CHO than CAF/PLA and PLA/PLA after exercise (P<0.05). Perceived exertion during exercise was significantly lower on CAF/CHO than the other three trials (P<0.05).
  
  
  CONCLUSIONS
  Taken together, this suggests that coingestion of caffeine and CHO has greater influence on immunoendocrine responses than neutrophil functional responses to prolonged exercise.
authors.affiliation: School of Sport and Exercise Sciences, Loughborough University, Leicestershire, UK. G.J.Walker2@lboro.ac.uk
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Walker
authors.forename: Oliver
authors.initials: O
authors.lastname: Finlay
authors.forename: Hannah
authors.initials: H
authors.lastname: Griffiths
authors.forename: James
authors.initials: J
authors.lastname: Sylvester
authors.forename: Mark
authors.initials: M
authors.lastname: Williams
authors.forename: Nicolette C
authors.initials: NC
authors.lastname: Bishop
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002110:Caffeine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002241:Carbohydrates / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004703:Endocrine System / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007107:Immune System / Q000187:drug effects* / Q000502:physiology; D007958:Leukocyte Count; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D016897:Respiratory Burst / Q000187:drug effects* / Q000502:physiology