Is there a hypercoagulable state in military fighter pilots?

A hypercoagulable state is associated with an increased incidence of cardiovascular disease, the most important cause of permanent grounding of flying personnel.The aim of our study was to investigate whether a hypercoagulable state is present in jet pilots, and whether it can be due to flight activity.To this purpose we studied Fibrinopeptide A (FPA), Thrombin-Antithrombin complexes (TAT) and D-Dimer (DD), sensitive biochemical markers of blood coagulation and fibrinolysis activation, in 10 jet pilots after a standardized training flight mission, and in a control group. Also evaluated before flight were 6 jet pilots.We were able to show increased thrombin and plasmin activity both in jet pilots compared to the control group, and after flight in the 6 pilots who were evaluated twice.We conclude that a hypercoagulable state due to flight activity is present in jet pilots after flight. Possible mechanisms involve an effect of psycho-physical stress mediated by a neuroendocrine response to flight activity, or an effect of chronic +Gz exposure on cardiovascular structure and function.