Acute Dynamic Exercise and Redox Regulation of Blood Coagulation in Pre-Hypertension.

An acute bout of exercise is associated with both increased oxidative stress and beneficial hemodynamic status in the human. Whilst in vitro evidence points to a redox regulation of coagulation no study has examined this relationship in vivo. 9 pre-hypertensive males, MAP = 106 ± 5 mmHg were studied for 2-hours following 30-minutes of cycle exercise at 70% maximal oxygen consumption. Subjects were followed post-exercise for 2-hours. Echocardiography assessed cardiac output ( ) determined systemic vascular resistance (SVR) [MAP/ ] and vascular conductance (SVC) [ /MAP]. Blood was sampled from an antecubital vein pre-, immediately post-, 1-hour (P1) and 2-hours post- (P2) exercise and corrected for hemoconcentration/dilution. Plasma was assayed for fibrinogen, international normalized ratio (INR), activated partial thromboplastin time (aPTT), activated partial thromboplastin time ratio (aPTTr), and prothrombin time (PT) parameters utilising coagulometric analysis. Lipid hydroperoxides (LOOH) were determined spectrophotometrically whilst blood was also assayed for selective antioxidants (HPLC). Exercise decreased SVR by 31% whilst elevating LOOH concentration by P1 (Pandlt;0.05). Both SVR and MAP (5mmHg; Pandlt;0.05) remained attenuated until P2. Fibrinogen, INR, aPTT, aPTTr, PT and antioxidant status were unmodified by the acute exercise bout. The concentration of LOOH post exercise (D) inversely correlated with DINR (r = -0.50; Pandlt;0.01). Exercise induced a vasodilation and hypotension. Coagulation was not modified when corrected for plasma volume change. In this in vivo model it appears that systemic oxidative stress is associated with activation of clotting