Exercise training improves endothelium-dependent vasodilation, whereas hypoxic stress causes vascular endothelial dysfunction. Monocyte- derived endothelial progenitor cells (Mon-EPCs) contribute to vascular repair process by differentiating into endothelial cells. This study investigates how high-intensity interval (HIT) and moderate intensity-continuous (MCT) exercise training affect circulating Mon-EPC levels and EPC functionality under hypoxic condition. Sixty healthy sedentary males were randomized to engage either HIT (3-minute intervals at 40% and 80%VO2max , n=20) or MCT (sustained 60%VO2max , n=20) for 30 minutes/day, 5 days/week for 6 weeks, or to a control group that did not received exercise intervention (n=20). Mon-EPC characteristics and EPC functionality under hypoxic exercise (HE, 100W under 12%O 2 ) were determined before and after various interventions.

Inclusion Criteria:

• Sedentary life
• Age 20~28

Exclusion Criteria:

• Smokers
• Users of medication/vitamins
• Any cardiopulmonary/hematological risk
• Regular exercise habits at least 1 year
• Exposed to high altitudes (>3000 m) for at least 1 year