Abstract
Regular exercise is theorized to reduce cardiovascular risk by attenuating
coagulation and augmenting fibrinolysis. However, these adaptations have not
been consistently observed during traditional exercise programs. The purpose
of this study was to examine hemostatic adaptations in healthy men following
four (4W) and eight (8W) weeks of high intensity interval training.
Twenty-one men (age=25±1 y; body mass
index=26.5±6.4 kg/m2)
completed eight weeks, three days/week of high intensity interval
training on a cycle ergometer. Activated partial thromboplastin time,
prothrombin time, and plasma concentrations of thrombin-antithrombin III,
fibrinogen, tissue plasminogen activator, and plasminogen activator
inhibitor-1 were assessed at baseline (BL), 4W, and 8W. Repeated measures
ANOVA were used to determine potential effects of training. There were no
significant changes observed for activated partial thromboplastin time
(BL=43.3±5.5, 4W=43.2±5.1,
8W=44.2±6.4 s); prothrombin time
(BL=13.2±0.9, 4W=13.0±0.6,
8W=13.1±0.8 s); thrombin-antithrombin III
(BL=6.0±2.3, 4W=5.8±2.3,
8W=5.6±3.1 ng/mL); tissue plasminogen
activator (BL=9.7±3.3, 4W=9.4±3.2,
8W=8.7±2.8 ng/mL); and plasminogen activator
inhibitor-1 (BL=19.0±17.5, 4W=19.3±17.0,
8W=18.9±18.9 ng/mL) (all p>0.05).
Fibrinogen was significantly lower at 4W
(238.6±70.3 mg/dL) compared to BL
(285.0±82.1 mg/dL; p<0.05) and 8W
(285.3±83.2 mg/dL; p<0.05). These findings
indicate that eight weeks of high intensity interval training does not
influence coagulation potential and/or stimulate fibrinolysis.
Key words
coagulation - fibrinolysis - thrombosis - hemostasis
