Psychological stress catalyses free radical–mediated activation of coagulation in humans

suggests that free radical-mediated oxidative stress is an upstream driver of psychological stress-induced activation of haemostasis, specifically altering clot quality. The TSST selectively shortened activated partial thromboplastin time (aPTT), indicating activation of the intrinsic/contact coagulation pathway. There were no changes in prothrombin time (PT) or D-dimer, suggesting haemostatic activation occurred without engaging fibrinolysis. The findings demonstrate that even a brief episode of emotional stress can increase thrombotic potential in healthy individuals and identify oxidative stress as a key mechanistic link and a potential therapeutic target for treating stress-related CVD.