Blood suckers fluid dynamics explain how quickly a vampire could drain your blood

Throughout human history there have been tales of vampires – bloodsucking creatures of folklore that prey on their victims by draining their life essence, usually via the blood.

To coincide with the 85^th anniversary of Universal Pictures’ ‘Dracula’ starring Bela Lugosi, using fluid dynamics students from the Department of Physics and Astronomy have examined how long it would take for the undead fiend to drain an average human’s blood – and have calculated that it would take only 6.4 minutes to drain 15 per cent of the blood from the external carotid artery in a human’s neck.

15 per cent was used as the benchmark as any more blood loss causes the heart rate to change, while less can be taken without affecting the circulatory system of a human.

Diagram defecting the blood flow out of the aorta as is modelled in the paper

Considering the human body has an average of 5 litres of blood and that a vampire might feasibly take 15%, in the study a vampire would drain 0.75 litres of blood, and by their calculations it would take 6.4 minutes to do so.

The students presented their findings in a paper for the Journal of Physics Special Topics, a peer-reviewed student journal run by the University’s Department of Physics and Astronomy. The student-run journal is designed to give students practical experience of writing, editing, publishing and reviewing scientific papers.

Course tutor, Dr Mervyn Roy, a lecturer in the University of Leicester’s Department of Physics and Astronomy, said: “Every year we ask each student to write around 10 short papers for the Journal of Physics Special Topics. It lets the students show off their creative side and apply some of physics they know to the weird, the wonderful, or the everyday.”

• Press release
• The paper ‘The Draining of a Lifetime’ is available here
• Read an article on why it is important to make physics and science education relevant and accessible to the public here