title: Timing of post-exercise carbohydrate ingestion: influence on IL-6 and hepcidin responses.
abstract: OBJECTIVE
  Carbohydrate ingestion prior and during exercise attenuates exercise-induced interleukin-6. This investigation examined if an analogous effect was evident for interleukin-6 and hepcidin response when carbohydrates were ingested post-exercise.
  
  
  METHODS
  In a crossover design, 11 well-trained endurance athletes completed two experimental trials. Participants completed an 8 × 3 min interval running session at 85 % vVO2peak followed by 5 h of monitored recovery. During this period, participants were provided with two 1.2 g kg(-1) carbohydrate beverages at either an early feeding time (immediately post-exercise and 2 h post-exercise) or delayed feeding time (2 h post-exercise and 4 h post-exercise). Venous blood samples were collected pre-, immediately post-, 3 and 5 h post-exercise. Samples were analysed for Interleukin-6, serum iron, serum ferritin and hepcidin.
  
  
  RESULTS
  Interleukin-6 was significantly elevated (p = 0.004) immediately post-exercise compared to baseline for both trials. Hepcidin levels were significantly elevated at 3 h post-exercise (p = 0.001) and 5 h post-exercise (p = 0.002) compared to baseline levels in both trials, with no significant difference between the two conditions and any time point. Serum iron was significantly increased from baseline to immediately post-exercise (p = 0.001) for both trials, with levels decreasing by 3 h (p = 0.025) and 5 h post-exercise (p = 0.001). Serum ferritin levels increased immediately post-exercise compared to baseline (p = 0.006) in both conditions.
  
  
  CONCLUSIONS
  The timing and ingestion of post-exercise carbohydrate ingestion do not appear to impact post-exercise interleukin-6 and hepcidin responses; this is likely a result of the interval running task inducing an inflammatory response and subsequent up-regulation of hepcidin.
authors.affiliation: School of Sport Science, Exercise and Health (M408), The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia. claire.badenhorst@research.uwa.edu.au.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Badenhorst
authors.affiliation: School of Sport Science, Exercise and Health (M408), The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
authors.forename: Brian
authors.initials: B
authors.lastname: Dawson
authors.affiliation: Sports Nutrition, Australian Institute of Sport, Gold Coast, Queensland, Australia.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Cox
authors.affiliation: Department of Laboratory Medicine (TML 830), Radboud University Medical Center, Nijmegen, The Netherlands.|Hepcidinanalysis.com, Geert Grooteplein 10 (830), 6525 GA, Nijmegen, The Netherlands.
authors.forename: Coby M
authors.initials: CM
authors.lastname: Laarakkers
authors.affiliation: Department of Laboratory Medicine (TML 830), Radboud University Medical Center, Nijmegen, The Netherlands.|Hepcidinanalysis.com, Geert Grooteplein 10 (830), 6525 GA, Nijmegen, The Netherlands.
authors.forename: Dorine W
authors.initials: DW
authors.lastname: Swinkels
authors.affiliation: School of Sport Science, Exercise and Health (M408), The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Peeling
mesh_terms: D000293:Adolescent; D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004334:Drug Administration Schedule; D004435:Eating; D015444:Exercise; D064451:Hepcidins / Q000097:blood*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007501:Iron / Q000097:blood; D008297:Male; D010807:Physical Endurance / Q000187:drug effects
chemical_list: D004040:Dietary Carbohydrates; D064451:Hepcidins; D015850:Interleukin-6; D007501:Iron
keywords: Cytokine; Interval running; Iron metabolism; Nutrition