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Cellular Immunity and Inflammatory Mediator Responses to Intense Exercise in Overweight Children and Adolescents
  1. Robert G. McMurray,
  2. Frank Zaldivar,
  3. Pietro Galassetti,
  4. Jennifer Larson,
  5. Alon Eliakim,
  6. Dan Nemet,
  7. Dan M. Cooper
  1. From the Pediatric Exercise Research Center (R.G.M., F.Z., P.G., J.L., A.E., D.N., D.M.C.), Department of Pediatrics, University Children's Hospital, University of California, Irvine, Irvine, CA; Department of Exercise and Sport Science (R.G.M.), University of North Carolina, Chapel Hill, Chapel Hill, NC; Department of Pediatrics (A.E., D.N.), Meir Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
  1. This research was supported by National Institutes of Health grants R01 HD26939-14, P01HD-048721, and MO1RR00827-S1.
  2. Address correspondence to: Dr. Pietro Galassetti, UCI GCRC Bionutrition/Metabolism Core, 101 The City Drive, Bldg 25, 2nd Floor, Orange, CA 92868; e-mail: pgalasse{at}


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 ≈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 α, IL-1β, 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.

Key words
  • pediatric obesity
  • proinflammatory cytokines
  • leukocytes
  • physical activity
  • immune responses
  • cytokines

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