Circulating hematopoietic progenitor cells in runners

J Appl Physiol (1985). 2002 Nov;93(5):1691-7. doi: 10.1152/japplphysiol.00376.2002.


Because endurance exercise causes release of mediators and growth factors active on the bone marrow, we asked whether it might affect circulating hematopoietic progenitor cells (HPCs) in amateur runners [n = 16, age: 41.8 +/- 13.5 (SD) yr, training: 93.8 +/- 31.8 km/wk] compared with sedentary controls (n = 9, age: 39.4 +/- 10.2 yr). HPCs, plasma cortisol, interleukin (IL)-6, granulocyte colony-stimulating factor (G-CSF), and the growth factor fms-like tyrosine kinase-3 (flt3)-ligand were measured at rest and after a marathon (M; n = 8) or half-marathon (HM; n = 8). Circulating HPC counts (i.e., CD34(+) cells and their subpopulations) were three- to fourfold higher in runners than in controls at baseline. They were unaffected by HM or M acutely but decreased the morning postrace. Baseline cortisol, flt3-ligand, IL-6, and G-CSF levels were similar in runners and controls. IL-6 and G-CSF increased to higher levels after M compared with HM, whereas cortisol and flt3-ligand increased similarly postrace. Our data suggest that increased HPCs reflect an adaptation response to recurrent, exercise-associated release of neutrophils and stress and inflammatory mediators, indicating modulation of bone marrow activity by habitual running.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, CD34 / analysis
  • Blood Cell Count
  • Blood Cells / cytology*
  • Blood Cells / immunology
  • Granulocyte Colony-Stimulating Factor / blood
  • Hematopoietic Stem Cells / cytology*
  • Hematopoietic Stem Cells / immunology
  • Humans
  • Hydrocortisone / blood
  • Interleukin-6 / blood
  • Male
  • Membrane Proteins / blood
  • Middle Aged
  • Physical Education and Training
  • Physical Endurance / physiology
  • Reference Values
  • Running / physiology*
  • Time Factors


  • Antigens, CD34
  • Interleukin-6
  • Membrane Proteins
  • flt3 ligand protein
  • Granulocyte Colony-Stimulating Factor
  • Hydrocortisone