Flatulence is a natural bodily function, but it can sometimes cause discomfort or signal gastrointestinal issues, making it an important symptom. Until recently, however, the “normal” amount of gas production had not been precisely determined. Brentley Hall from the University of Maryland told Scientific American: “We don’t know exactly what normal flatulence looks like. Without baseline data, it’s difficult to say whether a person’s gas production is within normal limits or not.”

In response to this medical need, Hall’s team from the Department of Cell Biology and Molecular Genetics developed Smart Underwear—the first portable device to measure flatulence, Euronews reports. The device discreetly attaches to underwear and uses electrochemical sensors to continuously monitor gas production in the gut.

The results of the experiment were published in Biosensors and Bioelectronics. Sensors recorded an average of 32 flatulence episodes per day in healthy adults—nearly double the previously cited medical literature figure of 14 ± 6 episodes. Researchers also noted a wide individual variation, ranging from 4 to 59 episodes per day.

“Objective measurement allows us to increase scientific rigor in a field that has long been difficult to study,” Hall commented.

The study included 38 volunteers, who wore the device during waking hours for a week while following a low-fiber diet at the start. Midway through the experiment, half of the participants were given additional fiber to observe its effect on gas production (flatulence increased with fiber). The researchers note that the wide range of daily flatulence challenges the assumption that “human physiology can be described by a single average value.”

Encouraged by the success of the first experiment, the team announced an initiative to create a “Human Flatulence Atlas.” The goal is to build an extensive database of gas production patterns across the population, linking hundreds of patterns to participants’ diets and gut microbiota composition.

“We know which microbes live in the gut, but we don’t know much about what exactly they are doing at each moment,” Hall said.

Experts believe such research could help develop more effective treatments for intestinal disorders.