Friday Weird Science: The Best Pose for Passing Gas

Jul 05 2013 Published by under Friday Weird Science, Uncategorized

Today's post fodder comes to you from the former NCBI ROFL, now "Seriously, Science?" over at Discover Blogs. I swear, I do TONS of pubmed searches for farts, but somehow never found this one.

In what position do you prefer to fart? Do you let them loose while lying down? Cut the cheese crouching? Squeak one out while standing? Squirt while sitting? Do you find one position more effective to really let it go?

I imagine that if you took a poll of your friends (your hopefully very honest friends who would all admit they farted and pooped rather than passing colorless, odorless, stackable cubes), they all would give you different answers. Maybe one prefers legs up to the chin, another prefers a slight 45 degree angle. I've been told (from the back of an herbal tea box offering yoga poses for various things) that the best position is a cat/cow, on hands and knees, with the head lowered to the floor and the butt in the air. Gas rises, you know (also, according to this tea, you breathe through one nostril for energy and the other for peace. This is clearly why I walk around with one nostril blocked).

But most of the time, we don't have the leisure to be carefully taking the forty-five degree angle of the buttocks. Often, we we're stuck standing, or we're in bed. And so all of us, at one point or another, come to a brief crisis in our lives...which is better for farting? Lying down? Or standing up?

Worry not, friends. SCIENCE is here.

Dainese et al "Influence of body posture on intestinal transit of gas" Neurogastroenterology, 2002


How do you test whether gas is best passed while standing or lying down? First, you take 8 very, very patient subjects. And then you need to control how much gas goes IN, so that you know how much is going to come OUT.

And so they took these poor participants (all healthy and checked to make sure they were very regular in their bowel habits), and they intubated them. At both ends. After carefully following a bean-free diet for a few days, the subjects got a tube in through the mouth, going all the way down to the jejunum, the first part of the small intestine. Through the...other end, they got a rectal catheter leading to a polygraph, and the needle would fluctuate every time gas was detected. Once the tubes were in places, the subjects were given gas in through the mouth (5.5% oxygen, the rest nitrogen and carbon dioxide). And of course, they were told to relax. Because nothing feels quite so natural as a tube coming out of each end. I really hope they were paid.

Each subject was tested twice for how fast the gas was gotten rid of, once while lying down at a 30% angle (why? Sciences does not disclose this), and once while standing up. And the winner?

Above you can see Figure 1 from the paper, which measures the amount of gas retained, standing vs lying down (supine). You can see that, well, first, the error bars are gigantic. Hey, when gas has to get out, it's got to get OUT. But there was a difference, people lying down had more gas retention (black squares) compared to standing up. Apparently standing up makes it all move a little better.

The authors were a little surprised, and so am I. You'd think that standing up, with gas rising as it does, it wouldn't really want to get...down and out, you know?

But they conclude that standing is better. Me, I'd like to see it compared to downward dog, see the REAL effect of rising gas. But I guess that's for another study.

Dainese R, Serra J, Azpiroz F, & Malagelada JR (2003). Influence of body posture on intestinal transit of gas. Gut, 52 (7), 971-4 PMID: 12801953

4 responses so far

  • Janne says:

    The possibilities for follow-up studies are truly endless... Under water, or at high altidude? Under high-altitude water? While singing? What about a rubber chicken? During a regular stressful work week versus a serene stay at a waterfront lodge in the Seychelles (the lead author selflessly volunteered)?

  • HCP says:

    At high enough altitude (military air transport,) we were told to stand, put one foot up on something, and rub our belly.
    Sounds silly, but we didn't want to be distracted when jumping out of the aircraft. With all that gear and stress, it's uncomfortable enough as it is; gotta focus.
    Now that I'm thinking about it, we simply accepted the rationale that if your ears could pop, gas in your guts would expand too. Hmmmmm.

  • [...] Favouring flatulence. How to know the best position to let it rip? Science! [...]

Leave a Reply