Could riding a roller coaster help people pass painful kidney stones?
“Basically, I had patients telling me that after riding a particular roller coaster [the Big Thunder Mountain Railroad] at Walt Disney World, they were able to pass their kidney stone,” said Wartinger in a released statement. “I even had one patient say he passed three different stones after riding multiple times.”
Kidney stones form when certain substances found normally in the urine — particularly calcium, oxalate and uric acid — become highly concentrated and harden into a “stone.” As these stones travel done the urinary tract, they may get stuck, blocking the flow of urine and causing severe pain.
Patients with kidney stones are usually told to drink water and to take pain relievers and, perhaps, ureter-relaxing medications until the stone passes out of the body in urine. Sometimes, however, the stone becomes lodged in the urinary tract or causes other complications. In those cases, surgery or a procedure that uses shock waves to break up the stones (lithotripsy) may be recommended.
Each year, about 1 million Americans seek medical care for kidney stones, including about 300,000 who show up at hospital emergency departments, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
A 3-D silicon model
To test what their roller-coaster-riding patients had told them, Wartinger and Mitchell took 60 rides on three different roller coasters at Walt Disney World in Orlando, Fla., while carrying 3-D printed models of kidneys made from clear silicon. The models contained different weights and sizes of kidney stones, which were suspended in urine.
“The maximum speed [of the roller coaster] was 35 mph,” they write, “and the model was subjected to sharp turns and quick drops during the ride, which last 2 minutes and 30 seconds.”
While on the roller coaster, the researchers placed each model “in an anatomic position inside a padded backpack held against the back of the seat at [kidney] height between the researchers.”
Sometimes, the researchers sat near the front of the roller coaster. Other times, they sat in a rear seat.
The effect of each ride on the kidney stones was observed and recorded. The data revealed a 70 percent success rate of passing stones — if the kidney was “riding” in the back three rows of the roller coaster.
The rate jumped to 100 percent if the stones were located in the upper chamber of the kidney, probably because they are helped more by gravity, say the researchers.
But only one of the Disney roller coaster rides — Big Thunder Mountain — worked. The other two tried in the study — Space Mountain and Aerosmith’s Rock ‘n’ Roller Coaster — failed to get any stones to pass.
The researchers believe those rides, which are faster and rougher than Big Thunder Mountain, have a G-force that holds the stones inside the kidney, not letting them move down the urinary tract.
“The ideal coaster is rough and quick with some twists and turns, but no upside down or inverted movements,” said Wartinger.
This study has several important limitations. Most notably, it used a silicone model of a kidney, not real kidneys in real people. Also, the model was based on the anatomy of one particular patient’s kidney. Another model of a kidney from another person might have led to different results.
Despite these and other limitations, Wartinger and Mitchel seem willing to jump to clinical recommendations. People with a stone — particularly in the upper chamber of the kidney — may want to consider riding a roller coaster to help it pass, they say.
They also suggest that people who have undergone lithotripsy may want to jump on a roller coaster as a type of follow-up treatment.
“Lithotripsy can leave remnants in the kidney which can result in another stone,” said Wartinger. “The best way to potentially eliminate this from happening is to try going on a roller coaster after a treatment when the remnants are still small.”
Prevention is best approach
Before you do that, though, it should be underscored that the hypothesis of the “roller coaster effect” on kidney stones is far from proven with this one, small study. Much, much more research is needed.
In the meantime, if you’re at risk of developing kidney stones — if, for example, you have a personal or family history of kidney stones, you’re obese, or you have a medical condition that increases the likelihood of stones forming — you can take some simple preventive steps. Here are some tips from the Mayo Clinic:
- Drink water throughout the day.
- Eat fewer oxalate-rich foods (such as rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate and soy products).
- Choose a diet low in salt and animal protein.
- Continue eating calcium-rich foods (which don’t raise your risk of kidney stones), but use caution with calcium supplements.
FMI: The study by Wartinger and Mitchell can be read in full on the JAOA website.