Physical pretraining of 102 Wistar rats during 30 days altered the reactions of haemostasis system to one-day hypobaric hypoxia. Decreased level of thrombinemia, ameliorated platelete, and plasma hаemostasis, increased anticoagulation, and fibrinolytic activity were observed. These changes were more pronounced in the experimental group of animals having experienced intensive physical training.

Suprathreshold physical activity causing distress in the organism can lead to the damage of various organs and systems including the hemostatic system. A modern integrated method of the hemostatic system assessment is thromboelastography. The purpose of the present study was to evaluate the state of the hemostatic system under one-time suprathreshold physical activity of various durations by means of thromboelastography. Experimental groups of rats were exposed to 4-hour and 8-hour physical activities in the form of forced running on a moving platform with the speed of 6-8 m/min. Immediately after the one-time physical activity, blood samples taken from rats were examined using the thrombelastograph in the Natem mode for 35 minutes. The 4-hour physical activity caused a reduction in coagulation time (CT) and an increase in the alpha angle and the maximum clot firmness (MCF). After the 8-hour activity, the thrombelastograph registered a reduction in coagulation time (CT), an increase in the alpha angle, a decrease in the clot formation time (CFT), a decrease in the maximum clot firmness (MCF), and a reduction in the maximum clot lysis (ML). The 4-hour physical activity resulted in partial activation of the hemostatic system without changing the fibrinolytic activity of blood plasm. The changes revealed in thromboelastography parameters indicate a high risk of the development of thrombotic readiness. The 8-hour physical activity causes a shift of the hemostatic system parameters in rats towards the increased clot formation: hypercoagulation, fibrinogen and platelet consumption, inhibition of fibrinolysis. The combination of changes in thromboelastogram parameters is indicative of the development of thrombotic readiness

Aimed at investigating influence of hypoxic hypoxia of different duration on haemostatic system state, the assessment of coagulogram in 152 Vistar rats 1 and 3 hours after single «lifting» to the height of 5500 m over sea level in pressure chamber and after daily 3 hours during 7 and 30 days. Activating influence of single hypoxic xypoxia was on hemostasis was revealed. While in-creasing duration of single impact , activation hemostatic system increased and anticoagulant and fibrinolytic properties of blood plasma decreased. According to the coagulogram data, prethrombotic changes developed in the form of coagulation activation, thrombocytes intake, decreased anti-thrombin III level and fibrinolytic activity on the 7-th day of hypoxia. On the 30-th day, de-creased hemostatic activity with increasing anticoagulant plasma blood reserve and restorating fibrinolytic activity.