Peripheral blood mononuclear cell derived endothelial progenitor cells (EPCs) are associated with cardiovascular function and their numbers decline with older age hypertensive risk and HIV infectionisease burden. Emergent evidence suggests that their functionality and presence may be related to cardio-autonomic and psychological functioning. This study examined whether in a sample of post-menopausal (PM) women (n = 5 HIV+/HTN + mean PM age = 53, n = 11 HIV+/HTN- mean PM age = 57, n = 6 HIV-/HTN + mean PM age = 53, or n = 14 HIV-/HTN- mean PM age = 53) ex vivo expansion of EPC counts derived from peripheral blood mononuclear cells covary with measures of high and low frequency heart rate variability. Mononuclear cells were isolated from each subject’s blood sample and incubated for 15 days in a fibronectin coated flask at 37 degrees Celsius, with the EPC medium changed every 2–3 days. Total cell, cluster, and spindle counts were recorded every 5 days for 2 weeks at 3 different time points labeled (t1, t2, and t3). After 10 days, EPC counts were significantly lower in HIV + HTN + and HIV + HTN- women compared to HIV-HTN+ (ps