Scientists actually looked into Santa’s ability to deliver giant bags of presents

Santa may only work one night a year, but he’s got a pretty tough job. He has to drive a sleigh at super high speeds, carry heavy sacks of presents, and walk on unstable rooftops—all while wearing a big, red, cumbersome suit.

Knowing the challenges Santa faces, especially with the extra girth he carries, researchers from the Department of Sport, Exercise and Health at the University of Basel in Switzerland decided to test Santa’s ability to perform his worldly duties. Yes, this really happened—though, to be fair, they ran the “study” mostly as a holiday joke.

“It seems plausible that only a tough, healthy, and sporty Santa Claus could face the difficulties of the overnight global delivery of billions of toys: Steering a sleigh with high velocities (just below light speed), carrying heavy weights, motivating reindeer and managing a tight delivery schedule require a physical conditioning that is nothing short of a Greek God,” explain the authors. Given that Santa appears to be old and out of shape, however, he is “likely to jeopardize Christmas Eve by slipping, tripping and falling.”

For the experiment, the researchers recruited 17 men with an average age of 30 to complete a series of tasks to measure gait, balance, and cognitive function—skills they believed a successful Santa would need. For extra laughs, they did not tell the participants what they were testing. “Whilst the investigator constantly giggled about the genuine study purpose,” explained the authors, “the included volunteers were unaware of the study aim.”

Half of the men were assigned to the “Santa group,” in which they donned a big red robe, white beard, and Santa wig, and were forced to carry a 44-pound sack throughout the experiment. (The researchers did not indicate how they arrived at this specific weight—it seems they were basically just going for “really heavy.”) The other half wore their street clothes, and were not asked to carry any sacks.

To measure gait, participants were asked to walk barefoot along a 10-meter walkway—while spelling a reindeer’s name backward, saying only every third letter. While they walked, their spatiotemporal gait parameters were measured using super science-y equipment. The scientists were basically looking at how their bodies moved.

To measure balance, participants were asked to stand perfectly still on a force plate—an instrument that measures the ground reaction force—generated by a body standing on or moving across it—with their hands placed on their hips. The participants were also asked to walk on a treadmill while counting backwards.

Turns out there was a pretty big difference between the Santas’ performance and the performance of men who weren’t carrying heavy sacks. Shocking, right?

“Our Christmas randomized controlled cross-over study indicates that spatiotemporal gait characteristics, static balance performance, and ground reaction forces during treadmill walking deteriorate when Santa Claus carries a 20 kg (44 pound) Christmas sack while suited up for Christmas present delivery,” the authors conclude.

The Santas did even worse when an additional cognitive task was thrown in, like saying a reindeer’s name backwards or counting backward by threes.

The combination of Santa’s age, a big suit, and the job’s necessary mental and physical demands “could lead to fatal fall(s) with a high chance of hospitalization of the beloved Santa Claus,” explain the authors. The researchers did not address how Santa has been so successful for so many decades. Or the fact that he may not be of this earth.

So what do they reckon the beloved guy should do? “We shed light on the fact that Christmas may not be saved unless Santa Claus completes physical training,” write the researchers. They suggest Santa participate in strength and balance training during the Christmas off season, reduce the amount of heavy presents he carries, and maybe even consider spreading the delivery period across several days. You know, to lessen the weight of that sack.

The study was published in the medical journal Gait & Posture as a fun holiday piece. “Since Santa is pictured jolly and obese, we thought this study might reveal the effects we were assuming in a funny way,” Lars Donath, the lead author and an expert in sports medicine, told me over email. “Science should not always be ultra serious.”

The real Santa has not commented on the study at the time of publication.