Effect of exercise on cytokines and growth mediators in prepubertal children

Pediatr Res. 1999 Oct;46(4):429-34. doi: 10.1203/00006450-199910000-00011.


Many of the anabolic effects of exercise are mediated through insulin-like growth factor-I (IGF-I), but in adolescents, brief exercise training leads to reductions, rather than the expected increase, in circulating IGF-I. Certain cytokines--interleukin-(IL) 1beta (IL-1beta), IL-6 (IL-6), and tumor necrosis factor-alpha--are increased by exercise in adults and are known to inhibit IGF-I. To test the hypothesis that these cytokines might play a role in the adaptation to exercise, we measured the acute effects of exercise on selected cytokines and growth factors in 17 healthy 8- to 11-y-old children (4 females). Designed to mimic patterns and intensity of exercise found in the real lives of American children, the exercise protocol consisted of a 1.5-h soccer practice (of which about 40 min constituted of vigorous exercise). Pre- and postexercise urine and saliva samples were obtained in all subjects and both blood and urine in nine subjects. The exercise led to significant increases in circulating tumor necrosis factor-alpha (18 +/- 7%, p < 0.05) and IL-6 (125 +/- 35%, p < 0.01) as well as a significant increase in the antiinflammatory cytokine IL-1 receptor antagonist (33 +/- 10%, p < 0.01). Urine levels of IL-6 were also substantially increased by exercise (440 +/- 137%, p < 0.0001). Circulating levels of IGF-I were reduced to a small but significant degree (-6.4 +/- 3.2%, p < 0.05), although IGF-binding protein-1 (known to inhibit IGF-I) was substantially increased (156 +/- 40%, p < 0.001). Cytokines are systemically increased after relatively brief exercise in healthy children. This increase may alter critical anabolic agents such as IGF-I and its binding proteins.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Cytokines / metabolism*
  • Epinephrine / blood
  • Exercise / physiology*
  • Female
  • Growth Substances / metabolism*
  • Humans
  • Hydrocortisone / blood
  • Insulin-Like Growth Factor I / metabolism
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-6 / metabolism
  • Male
  • Norepinephrine / blood
  • Sialoglycoproteins / metabolism
  • Tumor Necrosis Factor-alpha / metabolism


  • Cytokines
  • Growth Substances
  • IL1RN protein, human
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-6
  • Sialoglycoproteins
  • Tumor Necrosis Factor-alpha
  • Insulin-Like Growth Factor I
  • Hydrocortisone
  • Norepinephrine
  • Epinephrine