title: High-intensity interval training attenuates the exercise-induced increase in plasma IL-6 in response to acute exercise.
abstract: This aims of this study were to investigate the effects of carbohydrate availability during endurance training on the plasma interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-alpha response to a subsequent acute bout of high-intensity interval exercise. Three groups of recreationally active males performed 6 weeks of high-intensity interval running. Groups 1 (LOW+GLU) and 2 (LOW+PLA) trained twice per day, 2 days per week, and consumed a 6.4% glucose or placebo solution, respectively, before every second training session and at regular intervals throughout exercise. Group 3 (NORM) trained once per day, 4 days per week, and consumed no beverage during training. Each group performed 50 min of high-intensity interval running at the same absolute workloads before and after training. Muscle glycogen utilization in the gastrocnemius muscle during acute exercise was reduced (p < 0.05) in all groups following training, although this was not affected by training condition. Plasma IL-6 concentration increased (p < 0.05) after acute exercise in all groups before and after training. Furthermore, the magnitude of increase was reduced (p < 0.05) following training. This training-induced attenuation in plasma IL-6 increase was similar among groups. Plasma IL-8 concentration increased (p < 0.05) after acute exercise in all groups, although the magnitude of increase was not affected (p > 0.05) by training. Acute exercise did not increase (p > 0.05) plasma TNF-alpha when undertaken before or after training. Data demonstrate that the exercise-induced increase in plasma IL-6 concentration in response to customary exercise is attenuated by previous exercise training, and that this attenuation appears to occur independent of carbohydrate availability during training.
authors.affiliation: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 2ET, UK. J.P.Morton@ljmu.ac.uk
authors.forename: Louise
authors.initials: L
authors.lastname: Croft
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Bartlett
authors.forename: Don P M
authors.initials: DP
authors.lastname: MacLaren
authors.forename: Thomas
authors.initials: T
authors.lastname: Reilly
authors.forename: Louise
authors.initials: L
authors.lastname: Evans
authors.forename: Derek L
authors.initials: DL
authors.lastname: Mattey
authors.forename: Nicola B
authors.initials: NB
authors.lastname: Nixon
authors.forename: Barry
authors.initials: B
authors.lastname: Drust
authors.forename: James P
authors.initials: JP
authors.lastname: Morton
mesh_terms: D001706:Biopsy; D050260:Carbohydrate Metabolism / Q000502:physiology*; D016207:Cytokines / Q000097:blood; D050528:Diet, Carbohydrate-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000378:metabolism; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D012420:Running; D055815:Young Adult
chemical_list: D016207:Cytokines; D004040:Dietary Carbohydrates; D015850:Interleukin-6; D019344:Lactic Acid; D006003:Glycogen