Just about everybody has their go-to drink to get their workday started off right. Whether it’s a tall cup of coffee or a fresh mug of tea, people love a quick pick-me-up in the morning. But what about those who work the mandatory graveyard shift and still feel deadly tired—the vampires? How much time should they set aside to sit down with a warm body of blood before rushing off to vampire work? Now we know the answer to that question thanks to a morbidly curious (and hopefully totally human) team of physics students from England.

The team of students, currently studying at the University of Leicester, decided to take on the question of how much time would be required for a vampire to get his or her blood flow on the go, and it turns out that, according to their research paper published in the university’s Journal of Physics Special Topics, it would take about 6.4 minutes in total. But vampires have to be careful because humans have this lame tendency of dying if they’ve had too much of their vital fluids drained.

With this fact in mind, the students decided that a vampire wouldn’t drink any more than 15% of a given person’s blood, because after 15% blood loss, heart rate starts to change, and then it’s all downhill (into the grave) from there. The students also decided that their hypothetical vampires drink rather than suck blood out of their fleshy beverages’ necks, because the blood would flow freely through puncture holes, already pressurized by the circulatory system.

Using that 15% target (which would be about .75 liters of the body’s approximate 5 liter total) the students then calculated, based on the velocity of the blood flow through External Carotid Arteries in the neck and the size of the fang puncture wounds, how quickly a vampire could possibly drink a human’s blood.

Carotid arteries are colored in red.

So everybody thank science. Because even though it didn’t really give us a way to defend ourselves against vampires (no, garlic and crosses don’t count), at least we now know how long we’ll have to wait around as vampires get their fill of our blood. And as long as we don’t spell their names wrong on their orders, and let the soy-drinkers sacrifice themselves first, everything should be totally sanguine.

What do you think about this research on vampire blood drinking speed? Check out the Because Science video on vampire bloodletting below, then let us know your thoughts in the comments section!

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HT: Gizmodo

Images: Philip Burne-Jones, Gray’s Anatomy