This article hypothesizes that endothelial progenitor cells derived from bone marrow have a role in ongoing endothelial repair. Depletion of these cells over time, or any hindrance to their mobilization, contributes to endothelial dysfunction and cardiovascular disease progression. The results show a strong correlation between the number of circulating EPCs and cardiovascular health, and the conclusion is that an absence of sufficient circulating progenitor cells may affect the progression of cardiovascular disease.