Some bodily functions seem difficult to pull off simultaneously. We can’t sneeze with our eyes open, for example. But can we burp and fart at the same time, an act the Urban Dictionary has dubbed a furp? Or would this feat create some kind of gastronomic pressurized vacuum that would turn us inside out—or worse, make us explode?

Before we answer this pressing question, it’s helpful to understand how and why a person belches and emits flatulence in the first place. “When we eat, or drink carbonated sodas, or eat too fast, part of the process is that we collect air in the stomach,” Niket Sonpal, M.D., an adjunct assistant professor of clinical medicine in the department of basic biomedical science at New York City's Touro College of Osteopathic Medicine, tells Mental Floss. “Belching is a release of that stomach air. Eating also disperses air that’s already in the stomach, which can also cause belching. It’s not associated with the gas created with digestion.”

When we eat and swallow, we typically ingest about 1 tablespoon of air at the same time. (We swallow air throughout the day, too.) When enough air enters the stomach, the esophageal sphincters relax and allow the build-up of air to escape out of the mouth. If you add carbon dioxide from soda, the gas mixes with the air and makes the burps more pronounced.

Farting, on the other hand, is fueled by gases that build up in the intestine as the result of bacteria breaking down food in the gut. Certain gases, like methane, can result in an odor. So can foods that aren’t easily broken down, like beans or broccoli. An excess of gas can be absorbed by the body, but much of it needs to escape. The average person toots around 15 times per day. “Farting is part of digestion,” Dr. Sonpal says.

Belching is an act of the upper gastrointestinal tract; farting is an act of the lower gastrointestinal tract. It’s possible for a fart to escape out of the mouth if it’s held for too long, at which point gas will be reabsorbed by the body and subsequently exhaled. (This is not a burp, however.) And the air that could turn into a burp can be passed into the small intestine, and then the large intestine, creating a flatulent event.

But can we expel air out of both ends simultaneously?

“Most people could do both at the same time,” Dr. Sonpal says. “Both involve your stomach muscles contracting. You’re putting positive pressure on the abdominal space to push air out. But it usually won’t happen at the same time.”

Why? “The reason is because different muscle contractions occur. You contract the lower abdomen for passing gas and the upper abdomen for expelling air from the stomach. You won’t necessarily do both at the same time.”

The symphonic burp-and-fart is therefore a rare, though not impossible, phenomenon. So is there anything the body definitely can’t do while farting? Could we, for example, sneeze and fart? Yes, Dr. Sonpal says. But there can be consequences. “When you sneeze, you’re putting pressure into the abdomen. You’re bearing down. It’s the same when you pass wind. People can get leakage of urine from sneezing. Same with coughing or laughing. There can be leakage of urine or stool.” All the more reason to try and let your body sort itself out one emission at a time.

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