The Impact of Both Physical Exhaustion and Disruption of Circadian Rhythm on Blood Coagulation Factors in Rats

Abstract

Effects of circadian rhythm and different durations of physical exercise on blood clotting and fibrinolytic systems were measured in 60 male Wistar rats.

Rats were divided into control (n=20) and experimental groups (n=40). Blood samples were collected from rat tail tip at several stages; before and after physical activity in various functional conditions of pineal gland (activation and inhibition). The first group of  rats were housed in absolutely  light-  conditions (inhibition phase) for 10 days ,while the other group was kept in absolutely dark room for 10 days , at ambient temperature 23ºC±2ºC. A standard rat diet and water were supplied ad labium.

Our data showed that no statistically significant variation was found in blood clotting time and thrombin time of samples after a short – physical exercise in the normal subject, but there was a significant shortening in blood clotting time and thrombin time after strenuous exercise.

Physical activity significantly prolonged clotting time in animals with inhibited pineal gland.

Rats with activated pineal gland (dark phase), the clotting time prolonged after both durations (short and long exercise); thrombin generation time shortened.