While science has yet to conclusively prove the existence of vampires, some of the greatest minds in the field have spent some time looking into the matter… including a recent study by physics students at the University of Leicester in the UK.

Testing the principles of fluid dynamics, the students decided to calculate how long it would take for a vampire to drain enough blood to kill the average adult human.

The study took into account several factors: the assumption that a vampire would pierce the victim’s external carotid artery; the amount of blood loss that would eventually lead to heart failure (approximately 40 percent of a human body’s blood supply); the velocity of blood flow based on average blood pressure and arterial thickness; the density of human blood at room temperature; and the imagined size of the holes made in the artery by the vampire’s fangs.

The answer may come as a surprise to vampire fans: it would take a leisurely 17.3 minutes for the victim to die.

The team arrived at this figure based on the fact that fatal blood loss would require 15% of the body’s total blood supply to be drained every 6.4 minutes, and the fatal 40% would be reached after that time had nearly tripled. At that same rate, a complete exsanguination (loss of 100% of blood supply) would take just under 43 minutes.

Their results were published under the title “The Draining of a Lifetime” in Journal of Physics Special Topics, as an appropriately macabre tribute to the Universal classic DRACULA, starring Bela Lugosi — which premiered 85 years ago on Valentine’s Day. You can download a PDF copy of the study here.