Aerobic Interval Training Improves Muscular Oxygen Utilization and Depresses Vascular Endothelial Shedding in Sedentary Males

This study investigated the effects of aerobic interval (AIT) and moderate continuous (MCT) trainings on hemodynamics and oxygenation of skeletal muscles in men. Twenty sedentary males were randomized to perform either AIT (3‐minute intervals at 40% and 80% VO 2peak , n=10) or MCT (sustained 60% VO 2peak , n=10) for 30 minutes/day, 5 days/week for 5 weeks. A near‐infrared spectroscopy was employed to assess hemodynamics and oxygenation in vastus lateralis and gastrocnemius muscles. The level of circulating CD34 − /KDR + /phosphatidylserine + cells, which was defined as the shedding of endothelial cells from the vessel wall, was detected by three‐color flow cytometry. After the interventions, the AIT group exhibited a larger improvement in aerobic capacity than the NT group. Furthermore, the AIT regimen significantly (i) enhanced the ability of vastus lateralis muscle to extract oxygen during exercise, (ii) augmented the extents of hyperemic response and re‐oxygenation rate following ischemic stress in gastrocnemius muscle, and (iii) reduced the elevation of circulating CD34 − /KDR + /phosphatidylserine + cells caused by hypoxic stress. However, no significant changes in muscular hemodynamic function and vascular endothelial shedding were observed following 4‐week NT intervention. Hence, we conclude that the AIT regimen simultaneously improves muscular oxygenation and reduces the shedding of endothelial cells from the vasculature in sedentary males.