OK TMI: Why Do I Suddenly Have To Fart on a Plane As Soon As it Hits Cruising Altitude?

Ever settled into a flight after a smooth take-off—book out, noise-canceling headphones in—when all of a sudden you feel an urgent need to, um, fart, once the plane soars above the clouds? If you’re wondering why your digestive system always seems to act up while you’re hurtling through space and time in very close quarters with strangers, you’re not alone. It’s not bad luck or last night’s calamari. There’s an honest-to-goodness, scientific reason why flatulence is a thing at high altitudes, aka farting on planes is totally normal.

But first, what exactly is gas and why do we fart under normal circumstances?

Gas production is just a part of digestion. When you eat, carbohydrates pass through your small intestine in an undigested form. When this undigested food enters your large intestine, or colon, the “good,” bacteria that inhabit your gut microbiome go to work. These bacteria produce gas while they break down the hard-to-digest foods you’ve eaten.

Excess gas is removed from the body through burping or farting. Both are normal, daily occurrences. According to the Mayo Clinic, most people expel gas up to 20 times a day. Unfortunately, if you’re flying, gas may rear its smelly, embarrassing head at the worst possible time. And, holding it in may have health repercussions that include pain, bloating, indigestion, and heartburn.

What does altitude have to do with the urgent need to fart on planes?

Passing gas on planes and in other high-altitude locales is so commonplace that 1980s researchers studied and named it. That uncontrollable urge that has you squirming on high is scientifically known as High Altitude Flatus Expulsion (HAFE). The cause of HAFE is simple physics.

If you can remember your high school science class, you may be familiar with the concept of Ideal Gas, a predictive model that explains the behavior of gasses. But just in case that info isn’t locked in as a core memory, we turned to a gastroenterologist to explain how it works.

“The short and simple explanation about flatulence on planes has to do with the laws of physics and the Ideal Gas Law. The law basically states that gasses expand in volume as temperature rises, or pressure decreases,” says gastroenterologist Joseph Weiss, MD, FACP, FACG, AGAF, clinical professor of medicine at the University of California.

“As you go higher up in altitude, the atmospheric pressure decreases and, as the law dictates, intestinal gas increases in volume. More gas in the digestive tract equals more gas to expel,” he says.

And finally, 4 tips to avoid farting on planes

When you have the urge to pass gas while flying, holding it in may cause cramps and intense discomfort. If the seat belt sign refuses to budge and you can’t make a run for it, you may have to just let it go. (Yes, it’s embarrassing, but everyone will get over it, including you.)

If you are a known farting-on-planes-person, though, there are a few things you can do ahead of time that may help.

1. Try drinking more water the day before you fly. Avoiding soda and fizzy drinks can also help reduce the amount of gas you introduce into your system.
2. Eating slowly may also help. You take excess air in when you eat and drink. This is more likely to happen when you eat quickly.
3. Not everyone has the same food triggers for flatulence. If certain foods tend to make you gassy, avoid them the day before and the day of your trip. A few of the worst offenders include dairy (if you’re lactose intolerant), beans and lentils, cruciferous veggies (like broccoli and Brussels sprouts), starchy foods (hi, potatoes), and foods that contain the artificial sweetener sorbitol.
4. You can also try taking over-the-counter gas medications, like digestive enzyme supplements, during meals. These supplements contain enzymes that help your body break down the carbohydrates in gas-producing foods. This may reduce the amount of gas in your system, limiting the (literal) blow.

If you’re really worried or normally pass gas way more often than you think you should, give your healthcare provider a call. They may have further recommendations or suggest testing for conditions that can cause excess gas, like Celiac disease and inflammatory bowel disease. But if your problem really is just farting too much on planes, it’s okay—we all do it.