title: Cellular immunity and inflammatory mediator responses to intense exercise in overweight children and adolescents.
abstract: BACKGROUND
  Obesity modifies inflammatory mediators, but little is known about how obesity modifies the inflammatory responses of exercising children. This study assessed the acute effect of exercise on inflammatory mediators in overweight children.
  
  
  METHODS
  Twenty-eight overweight (OW) youth (body mass index > 85%) and 30 normal-weight (NW) controls of the same proportions of age and gender performed 10 2-minute bouts of cycle ergometry exercise above the anaerobic threshold, with 1-minute rest intervals between bouts. Pre- and postexercise blood samples were collected for white blood cell subpopulation and inflammatory cytokines.
  
  
  RESULTS
  Baseline leukocyte populations were higher in OW youth (p < .05). Exercise increased most leukocyte subtypes for both groups (p < .05). Granulocytes remained elevated 2 hours postexercise (p < .05) for both groups, whereas monocytes remained elevated 2 hours postexercise for the OW children. Natural killer (NK) cells dropped below baseline 2 hours postexercise. Exercise significantly decreased CD4 and CD8 cells, which remained depressed 2 hours postexercise in the OW children. Baseline levels of interleukin (IL)-6 were congruent approximately 64% higher in OW children (p < .001). Exercise increased IL-6 in both groups (p < .001), which further increased 2 hours postexercise (p < .05). Tumor necrosis factor alpha, IL-1beta, and IL-1 receptor antagonist did not change with exercise.
  
  
  CONCLUSIONS
  Elevated baseline leukocyte subtypes and IL-6 levels in OW children suggest that childhood obesity is associated with a chronic low-grade inflammatory state. The acute inflammatory response to intense exercise appears to be similar between NW and OW children for most markers, but the depression of NK, CD4, and CD8 cells 2 hours postexercise suggests that an acute risk of mitogen-induced inflammation may exist in OW children after high-intensity exercise.
authors.affiliation: Pediatric Exercise Research Center, Department of Pediatrics, University Children's Hospital, University of California, Irvine, Irvine, CA, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: McMurray
authors.forename: Frank
authors.initials: F
authors.lastname: Zaldivar
authors.forename: Pietro
authors.initials: P
authors.lastname: Galassetti
authors.forename: Jennifer
authors.initials: J
authors.lastname: Larson
authors.forename: Alon
authors.initials: A
authors.lastname: Eliakim
authors.forename: Dan
authors.initials: D
authors.lastname: Nemet
authors.forename: Dan M
authors.initials: DM
authors.lastname: Cooper
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D016207:Cytokines / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D053583:Interleukin-1beta / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D016176:T-Lymphocyte Subsets / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D015850:Interleukin-6; D017472:Receptors, Interleukin-1; D014409:Tumor Necrosis Factor-alpha