The Fear F8ctor Study - Does Fear Induce a Blood Curdling State?

Rationale: For centuries the term "blood curling" has been used to describe extreme frightening situations. The term dates back to the medieval physiology, it was believed that the human body contained four chief fluids, blood, phlegm, bile and black bile. It was thought that fear or horror would 'run the blood cold' or 'curdle' (solidify). To date large parts of the complex mechanism of the coagulation cascade have been unravelled and many risk factors for clotting, i.e., thrombosis have been identified. However, the origin of this ancient theory has never been studied and it remains unknown if fear induces the coagulation system. Objective: To explore the effects of acute fear on the coagulation system while sitting still. The investigators will compare systemic coagulation markers before and after both movies in each subject: 13 subjects will be exposed to the horrifying movie first, followed by the dull movie (at least 1 week later). Both movies will be shown on the same day of the week, at the same time of the day and will last approximately 90 minutes. One group of 13 will first view the horrifying movie, followed by the dull move the next week (Group I) and 13 subjects will be exposed to the dull movie first, followed by the horrifying movie (Group II). Spacious seats will be used to avoid the effect of immobilisation due to tight cinema seats. Blood is drawn at four time points (TP); (0) before the first movie (baseline), after the first movie (1), before the second movie (2) and after the second movie (3). A needle puncture is used to collect 12 ml of blood at each time point. Individual markers of coagulation activity will be determined from the blood samples. Pulse rates will be measured and an anxiety/fear score will be collected from each student for both movies.