title: Effect of exercise intensity on the cytokine response to an acute bout of running.
abstract: OBJECTIVE
  We compared the effects of exercise intensity (EI) on the cytokine response to an acute bout of running.
  
  
  METHODS
  Ten males (mean ± SD VO(2max)= 56.2 ± 8.1 mL·min(-1)·kg(-1)) completed three, counterbalanced, 8-d trials. After three control days, on day 4, participants completed 60 min of running at 55%, 65%, and 75% VO(2max). The cytokines tumor necrosis factor (TNF)-α, interleukin-1β (IL-1β), IL-6, and IL-1 receptor antagonist (ra), and creatine kinase were measured during and for 3 h after exercise and on four follow-up days (FU1-FU4).
  
  
  RESULTS
  RER was higher at 75% V(O2max) compared with both 55% (P < 0.001) and 65% (P < 0.01) VO(2max). IL-1β was undetectable in six participants. There was a small (18%-27%) increase in TNF-α during exercise but no effect of EI. IL-6 concentrations peaked at the end of exercise, with a greater increase at 75% VO(2max), resulting in higher concentrations at the end of exercise and at 30 min after exercise compared with 55% (P < 0.001) and 65% VO(2max) (P < 0.01). IL-1ra concentrations peaked at the end of exercise at 75% VO(2max), resulting in higher (P < 0.05) concentrations at 1-2 h after exercise compared with 55% and 65% VO(2max). Creatine kinase was increased at FU1 and FU2, but there was no effect of EI.
  
  
  CONCLUSIONS
  Sixty minutes of treadmill running at 75% VO(2max) results in a greater increase in IL-6 but not TNF-α compared with 55% and 65% V(O2max). The higher IL-1ra concentrations at 75% VO(2max) might be related to the higher IL-6 concentrations that precede them.
authors.affiliation: Human Protection and Performance Enhancement, QinetiQ, Farnborough, UK.
authors.forename: Jonathan Paul Richard
authors.initials: JP
authors.lastname: Scott
authors.forename: Craig
authors.initials: C
authors.lastname: Sale
authors.forename: Julie P
authors.initials: JP
authors.lastname: Greeves
authors.forename: Anna
authors.initials: A
authors.lastname: Casey
authors.forename: John
authors.initials: J
authors.lastname: Dutton
authors.forename: William D
authors.initials: WD
authors.lastname: Fraser
mesh_terms: D000328:Adult; D003402:Creatine Kinase / Q000097:blood; D016207:Cytokines / Q000097:blood* / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D016207:Cytokines; D003402:Creatine Kinase