Hypoxic exercise training improves cardiac/muscular hemodynamics and is associated with modulated circulating progenitor cells in sedentary men

Int J Cardiol. 2014 Jan 1;170(3):315-23. doi: 10.1016/j.ijcard.2013.11.005. Epub 2013 Nov 12.


Background: Circulating progenitor cells (CPCs) improve cardiovascular function and organ perfusion by enhancing the capacities of endothelial repair and neovasculogenesis. This study investigates whether exercise regimens with/without hypoxia affect cardiac and muscular hemodynamics by modulating CPCs and angiogenic factors.

Methods: Forty sedentary males were randomly divided into hypoxic (HT, n=20) and normoxic (NT, n=20) training groups. The subjects were trained on a bicycle ergometer at 60%VO(2max) under 15% (HT) or 21% (NT) O2 conditions for 30 min daily, five days weekly for five weeks.

Results: After the five-week interventions, the HT group exhibited a larger improvement in aerobic capacity than the NT group. Furthermore, the HT regimen (i) enhanced cardiac output (Q(H)) and perfusion (Q(M))/oxygenation of vastus lateralis during exercise; (ii) increased levels of CD34(+)/KDR(+)/CD117(+), CD34(+)/KDR(+)/CD133(+), and CD34(+)/KDR(+)/CD31(+) cells in blood; (iii) promoted the proliferative capacity of these CPC subsets, and (iv) elevated plasma nitrite/nitrate, stromal cell-derived factor-1 (SDF-1), matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor-A (VEGF-A) concentrations. Despite the lack of changes in Q(H) and the number or proliferative capacity of CD34(+)/KDR(+)/CD117(+) or CD34(+)/KDR(+)/CD31(+) cells, the NT regimen elevated both Q(M) and plasma nitrite/nitrate levels and suppressed the shedding of endothelial cells (CD34(-)/KDR(+)/phosphatidylserine(+) cells).

Conclusions: The HT regimen improves cardiac and muscular hemodynamic adaptations, possibly by promoting the mobilization/function of CPCs and the production of angiogenic factors.

Keywords: Circulating progenitor cells; Exercise; Hemodynamics; Hypoxia.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cardiovascular Physiological Phenomena
  • Chemokine CXCL12 / blood
  • Endothelium, Vascular / physiology
  • Exercise / physiology*
  • Exercise Test
  • Healthy Volunteers
  • Heart / physiology*
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / physiology*
  • Hemodynamics / physiology*
  • Humans
  • Hypoxia / physiopathology*
  • Male
  • Matrix Metalloproteinase 9 / blood
  • Muscle, Skeletal / physiology
  • Nitrates / blood
  • Nitrites / blood
  • Oxygen / administration & dosage
  • Oxygen / blood
  • Oxygen Consumption / physiology
  • Sedentary Behavior*
  • Stroke Volume / physiology
  • Vascular Endothelial Growth Factor A / blood
  • Young Adult


  • CXCL12 protein, human
  • Chemokine CXCL12
  • Nitrates
  • Nitrites
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • MMP9 protein, human
  • Matrix Metalloproteinase 9
  • Oxygen