High-intensity interval training modulates thrombotic susceptibility in metabolic syndrome: Attenuation of plasma PAI-1 and fibrinogen via ameliorated metabolic dysfunction

Metabolic syndrome (MetS) elevates thrombotic risk through dysregulated coagulation factors, including plasminogen activator inhibitor-1 (PAI-1) and fibrinogen, driven by visceral adiposity and metabolic dysfunction. High-intensity interval training (HIIT) improves cardiometabolic health, but its effects on hemostatic markers in MetS remain underexplored. Twenty-four men with MetS (ATP-III criteria; age 44.4 ± 5.4 years, BMI 31.7 ± 2.3 kg·m⁻²) were randomized to HIIT (n=12) or control (n=12). HIIT comprised 3 sessions/week for 8 weeks (4 × 4-min intervals at 90% HRmax, interspersed with 3-min active recovery at 70% HRmax). Fasting plasma PAI-1, fibrinogen, insulin resistance (HOMA-IR), body composition, and lipid profiles were assessed pre/post-intervention. HIIT significantly reduced PAI-1 (−30.7%, p<0.001) and fibrinogen (−21.8%, p<0.001) versus controls. Concurrent improvements occurred in HOMA-IR (−20.6%, p<0.001), body fat (−3.8%, p<0.05), systolic/diastolic BP (−7.5%/−5.2%, p<0.05), LDL-c (−5.6%), triglycerides (−9.4%), and HDL-c (+3.0%; all p<0.05). Control group exhibited no significant changes. HIIT attenuates prothrombotic risk in MetS, evidenced by reductions in PAI-1 and fibrinogen. These hemostatic improvements are mechanistically linked to ameliorated metabolic dysfunction, highlighting HIIT’s role in modulating adipose tissue–vascular cross talk.