Kidney stones — hard deposits made of minerals and salts that form inside your kindeys, according to Mayo Clinic — are bad news. Many people compare the pain of passing them to the pain of giving birth; but according to some Reddit users, kidney stone pain might just be even worse:
David Wartinger, a urologist at Michigan State University, saw that multiple patients had come home from Disney World in Florida having passed their kidney stones. Wartinger noticed that each patient shared one more common factor: the Big Thunder Mountain Railroad roller coaster. One patient had even reportedly gone on the coaster three consecutive times — and had passed a stone each time.
So, what did Wartinger do? He went to Disney World, of course. He and a team member 3D-printed a transparent kidney, filled it with urine and a few kidney stones, and hopped on Big Thunder Mountain Railroad. The kidney, along with Wartinger, went on the roller coaster 20 times.
That's a lot of Thunder Mountain.
In an interview with Gizmodo, Wartinger said, "As far as having to ride the coaster repeatedly, honestly, the first five to six times were great. By the end we were just gritting our teeth and wishing to be done."
According to Gizmodo, the researchers repeated the test on Space Mountain and the Walt Disney World Railroad, totaling a painful 60 roller coaster rides (all in the name of science, of course).
According to the study, about 17 percent of kidney stones passed through the kidney while sitting in the front of Big Thunder Mountain Railroad. But, at the back of the coaster, a whopping 64 percent passed.
The same experiment didn't work so well on Space Mountain and the Walt Disney World Railroad.
The team concluded that riding the roughest coaster in town probably isn't the best way to go if you're looking for kidney stone relief. It's the moderately intensecoasters that are going to give you the best chance.
"An ideal roller coaster to facilitate [kidney stone] passage subjects riders to quick drops and sharp turns, but it does not exceed 40 miles per hour or invert riders," Wartinger says.
The video below shows Wartinger himself reporting his methods and findings. He uses a lot of intimidating language, but you'll get the gist of it.