title: Increased inflammatory response of blood cells to repeated bout of endurance exercise.
abstract: OBJECTIVE
  The aim of the present study was to assess the effects of two 30-min consecutive exercise bouts on a treadmill at 80% VO2max separated by a 4-h rest interval, on blood cell counts and the production of tissue factor, cytokines, and eicosanoids in lipopolysaccharide (LPS)-stimulated blood.
  
  
  METHODS
  Blood samples were taken from eight endurance athletes (mean+/-SD: age, 23.4+/-1.6 yr; VO2max, 66.0+/-6.4 L.min.kg), both immediately before and after each exercise bout. Cell counts were performed, and the heparinized blood was subjected to LPS-stimulation for 2 h.
  
  
  RESULTS
  There was a significant rise in white blood cell counts after the first exercise bout (81%, P<0.001), increasing to 123% (P<0.001) after the second bout. After the first and second runs, the tissue factor activity in LPS-stimulated monocytes was enhanced by 70% (not significant) and almost 200% (P=0.012), respectively, compared with baseline values. The high monocyte responsiveness after the second bout remained undiminished 2 h later. Similarly, the interleukin (IL)-8 production had risen 70% (P=0.022) after the first run and 100% (P=0.005) after the second run, relative to baseline values. IL-6 or leukotriene B4 levels did not change significantly. The rise in LPS-induced thromboxane B2 was 80% (P=0.024) after the first run and 63% after the second run (P=0.071, not significant). VO2max correlated negatively with the concentration of granulocytes immediately after the second exercise bout (R=0.864, P=0.006).
  
  
  CONCLUSIONS
  The results of this study are evidence that two physical exercise bouts separated by a 4-h rest are associated with an enhanced propensity of the blood cells to generate tissue factor activity and some proinflammatory products compared with one exercise bout.
authors.affiliation: Department of Biochemistry, Institute of Medical Biology, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Jorid
authors.initials: J
authors.lastname: Degerstrøm
authors.forename: Bjarne
authors.initials: B
authors.lastname: Østerud
mesh_terms: D016207:Cytokines / Q000097:blood; D015777:Eicosanoids / Q000097:blood; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000503:physiopathology; D007958:Leukocyte Count; D007962:Leukocytes / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D009664:Norway; D005082:Physical Exertion; D013925:Thromboplastin
chemical_list: D016207:Cytokines; D015777:Eicosanoids; D013925:Thromboplastin