Relation between acute hypoxia and activation of coagulation in human beings

The risk of venous thrombosis may be increased during aeroplane flights, which may, partly, relate to activation of coagulation by hypoxia that is caused by the reduction of pressure in the aircraft cabin. To find out whether hypoxia activates coagulation, we exposed eight healthy human participants to 8 h of isocapnic hypoxia and 8 h of air as a control. Venous blood was sampled before and after the exposure and analysed for markers of activated coagulation. There were no significant changes. We conclude that hypoxia has no major effect on coagulation in the general population.