For many years, it was believed that the sole mechanism for postnatal growth of new blood vessels is angiogenesis, occurring through vascular sprouting and intucesseption. Today, accumulating evidence indicates that peripheral blood contains bone marrow derived endothelial progenitor cells (EPC). This study was undertaken to investigate the effects of hypoxia and/or exercise (90min) on endothelial progenitor cells and angiogenic growth factors. Blood samples were taken before, 0h and 3h after exercise and were analysed by ELISA for EPO, VEGF and IL-6. Plasma was also used for migration assays, to study the effects on EPC. EPO showed a significant increase 3h after exercise in hypoxia. IL-6 increased significantly 0h after exercise but seemed to be independent of hypoxia. VEGF showed no changes. The migratory activity of EPC was not stimulated after various treatments.

Especially the combination of hypoxia and exercise should have induced, according to the current state of knowledge, a mobilization of EPCs. It appears as if the exercise stimuli were not intense enough to mobilize EPCs or other additional factors, not determined in this study are responsible for mobilization.