Hypoxic Exercise Training Affects Thrombin Generation by Modulating Platelet‐derived Procoagulant Microparticles under Shear Flow

Abstract

This study investigated how exercise training with/without hypoxia affects thrombin generation (TG) mediated by platelet‐derived micropraticles (PDMPs) under physio‐pathological shear flows. Seventy five sedentary males were randomly divided into five groups. The subjects in each group (n=15) were exposed to 21% (NC) or 15% (HC) O2 at rest or were trained at 50% of Wmax under 21% (NT) or 15%O2 (HAT), or 50% of heart rate reserve under 15%O2 (HRT) for 30 minutes daily, 5 days weekly for 4 weeks. Before the intervention, strenuous exercise increased the levels of coagulant factor V/Va (FV/FVa)‐/FVIII‐/tissue factor (TF)‐rich and phosphatidylserine (PS)‐exposed PDMPs and the rate of TG in PDMP‐rich plasma (MRP) under 100 dyne/cm2 of shear stress. The NT and HRT, but not NC and HC, for 4 weeks attenuated the enhancements of shear‐induced FV/FVa‐/FVIII‐/TF‐rich and PS‐exposed PDMP formation and TG rate in MRP by severe exercise. Conversely, the HAT regimen promoted shear‐induced formation and procoagulant activation of PDMPs, concurrence with increasing plasma FV and TF levels at rest or following exercise. We conclude that a hypoxic exercise regimen, that performs a relative‐intensive workload according to exercise heart rate, may depress shear‐mediated procoagulant activity of PDMPs during exercise.