Want to Pass a Kidney Stone? Try Riding a Roller Coaster

Kidney stones don’t exactly feel like a trip to the amusement park—but, as Gizmodo reports, a study suggests that riding on a moderate-intensity roller coaster might make it easier to pass small ones. The research was published in the Journal of the American Osteopathic Association.

Kidney stones are solid clumps of salts and minerals that form from highly concentrated substances normally found in urine. They range in size from as small as a grain of sand to as large as a golf ball. Physicians don’t quite know what causes a kidney stone to pass through the urinary canal, although they have noted that some physical activities—manual labor, bungee jumping, and trampoline bouncing, to name a few—can loosen them. Nevertheless, anyone who’s ever suffered a large one can attest that the process can be incredibly painful. (It’s often even compared to childbirth.) Kidney stones are also expensive, costing nearly $4 billion each year in treatment fees.

David Wartinger, a urologist at Michigan State University, noticed that multiple patients had passed kidney stones while on spring break at Disney World in Orlando. All of them had been riding the Thunder Mountain Railroad rollercoaster—and one male patient who rode it three times had even passed a different stone after each consecutive session.

Noticing a therapeutic opportunity, Wartinger teamed up with study co-author Marc Mitchell to 3D-print a clear silicone model of a kidney—specifically, the organ of the man who’d experienced the trio of rollercoaster relief. They then filled it with urine and placed three different-sized kidney stones inside the model’s upper, middle, and lower passageways. The sealed kidney was transported to Disney World, where the researchers put the mock organ in a backpack, held it between them (right next to their real kidneys), and rode Thunder Mountain Railroad 20 times.

The researchers found that sitting in the back of Big Thunder Mountain Railroad yielded a stone passage rate of nearly 64 percent. In contrast, front seat rides resulted in a nearly 17 percent passage rate. They think the jostling they experienced in the rollercoaster’s back helped knock the stone loose from the kidney, down into the ureter, through the bladder, and out of the body.

"In all, we used 174 kidney stones of varying shapes, sizes, and weights to see if each model worked on the same ride and on two other roller coasters," Wartinger said in a press statement. "Big Thunder Mountain was the only one that worked. We tried Space Mountain and Aerosmith's Rock 'n' Roller Coaster and both failed." (These rides, according to the urologist, are so fast and violent that they actually trap the stone inside the kidney.)

The preliminary study's findings "support the anecdotal evidence that a ride on a moderate-intensity roller coaster could benefit some patients with small kidney stones," Wartinger concluded.

By now, the researchers have tried the test on Big Thunder Mountain Railroad 200 times, NBC News reports. They are hopeful that their findings can be replicated on other coasters, and that riding these amusement park attractions might help people avoid surgery or painful blockages.

But since every person has his or her own unique kidney passage pattern, not everyone will experience the same relief as Wartinger’s patient. Different roller coasters might provide a better fix—and for some people, other movement-yielding activities might be more effective.

In the meantime, Wartinger hopes to eventually conduct a clinical trial, using real people with kidney stones. To guarantee precise results, he'd give them an ultrasound right before a rollercoaster ride, and another one after to see if the stones moved.

Moderate-intensity rollercoasters probably aren’t the ultimate clinical fix for people with kidney stone woes. However, Wartinger is hopeful that they might help people pass small stones before they grow larger, or stones that have been broken into fragments by ultrasound procedures. “If you have a kidney stone, but are otherwise healthy and meet the requirements of the ride, patients should try it,” Wartinger told The Atlantic. “It’s definitely a lower-cost alternative to health care."