Holding in your fart

(The recent subdued-sneeze question got me thinking…)

As some of you may know, it is possible to hold in a fart. I don’t do so often, but there are situations that are too close for comfort where I feel that I must. Sometimes, holding in a fart causes it to dissipate inward (or at least it feels that way). Often this results in sharp pain in big muscles (usually leg muscles).

What exactly is happening in these situations, and what is causing the muscle pain being felt? I assume that this can’t be healthy? Should I worry about doing this, even if only once in a while?

Pain in your intestines is almost always from the pressure of gas or water pushing against the sensitive sides. Holding in a fart means applying back pressure against the peristalsis that is trying to move the air out. How much pain you feel will depend on the amount of air and pressure.

The air will come out eventually. You may not even feel it when it does.

You are extremely unlikely to be able to physically hurt yourself by holding in a fart. If the pressure is that great, it will be greater than the amount of pressure you can apply to your sphincter muscles.

I can’t explain why you would feel pain in your leg muscles. Perhaps your body is just transferring pain from the other muscle activity.

“God alone knows how many times our bellies, by the refusal of one single fart, have brought us to the door of an agonising death.”

Dissipation I think is either A) when the gas retreats back behind an earlier “valve” or cutoff point or B) when the gas is released, but your sphincter is so tight that only the smallest air molecules squeeze through and the larger volatile (smelly) molecules are filtered out (in).

I could see this causing pain in the bowel area as it causes distension of the bowel walls, but I can’t imagine why it would cause muscle pain, or any pain in the leg area…

Holding your farts in can cause spontaneous human combustion. Cite.

Garrison Keillor’s cowboy Lefty, on this subject said that holder-inners can be spotted by their tight skin and nervous dispositions. “It’s not safe to smoke around them,” he said. “It’s best to avoid them.” :eek:

Man, that’s some tight ass.

A) No.

B) No.


I don’t think your sphincter can close at the molecular level. But, then again, I’ve been known to clear out entire rooms, sections of bleachers, and forced people to pull over while driving. Also, IANAB.

Ignotius, is that you? Would you like a Dr. Nut?

You’ve never met my last landlord.

Your alternative explanation being? It’s fairly obvious to anyone who has held in a bowel movement that stuff can retreat.

And I’ve definitely had great big farts waiting to happen that I’ve managed to do something that felt like slowly deflating it without releasing any odor.

If the sphincter can be tight enough to prevent a fart all together I don’t see why it can’t be tight enough to filter out things on the molecular level. Especially if the mucus lining is involved. It may be that the air molecules are diffusing through the mucus but the odor molecules are getting trapped. There are air filters that work this way, running the air through water to trap contaminants.

But again, if no, why not, and how else?

You really don’t want to hold it in.

Imagine - you close off to stop eructation. The gas hangs around, accumulating in the colon. Eventually, as it builds up, it starts moving back, through the intestines, running past all the crap (technical term) already there. Eventually, the intestines are so full of gas and your butt clenched so tight, that it can only bubble out one way - into the stomach.

And stomach gas is just a burp away from release, via your nasal cavities and tongue. :eek:

Relax and let it out, for goodness sake :wink:


Because the stinky molecules (hydrogen sulfide) are smaller than the odorless molecules (methane and carbon dioxide).

A) The last actual valve is at the entrance to the large intestine. There is no possible way that you are pushing the gas in the rectum back more than five feet through that one-way valve. Physiologically impossible.

B) Similarly, muscles working at the molecular level is physiologically impossible. You obviously have no conception of how small a molecule is. A release of gas involves millions, billions, possibly trillions of molecules. That we can squeeze tightly enough to filter out differences of size in particular molecules is ludicrous.

I already stated that the air will leak through if it doesn’t come out in a bubble. And I stated that you may not feel it. Testing shows that each of us farts many times a day without being consciously aware of it. That’s because the physical structure of the anus is many times too large to prevent small quantities of air from escaping. A molecular filter? Please.

It doesn’t have to be an actual valve, just a squeeze point. It’s an obvious fact that both feces and farts can retreat. There’s obviously some sort of barrier. If you can specify what you think is the correct term for this barrier that’s fine, but the general principle hasn’t changed. You still haven’t explained the phenomenon.

Again, as I stated, I never claimed that the tightness of the squeeze was the actual mechanism of filtering, just the proximate cause. I theorized that perhaps when the sphincter was closed, the air was forced through the mucus, creating some sort of dampening effect on the volatile molecules. Maybe the air is just released with less pressure and so less of it is forced through the fabric of one’s clothing.

It’s fine and dandy to criticize a theory, although it usually helps if you actually read the theory and don’t misconstrue it while at the same time being condescending. But you still haven’t explained the phenomenon. It’s a fact that a tighter squeeze can release the gas while minimizing the odor. If you don’t like the mucus theory, come up with your own.

That barrier is called the anus.

Feces and farts do not retreat. They stay in the rectum. If you disagree, find an actual cite that says differently, not just your unscientific notions of what happens inside your body.

It’s not a fact. It’s an assertion on your part.

Show some evidence that it’s true rather than some bizarre belief on your part based solely on your personal experience, chosen from a highly selective number of events.

Neither of these claims is obvious to anyone with even a passing familiarity with human physiology.

I think that there may be an explanation for what jackdavinci has felt, but maybe has not understood.

In general, pressure on the anus (for gas or solids) is generated by peristaltic motions of the colorectal walls. This keeps happening during, it’s what your gut does. Sometimes, as material moves closer to the anus, these peristaltic motions create the feeling that drives us to evacuate or eructate. But in general, the bowel is not full by any means. So a tight clenching of the anal sphincter can be enough to hold it closed against the pressure of the peristaltic motion, and can (because it is semi-autonomous) shut those motions down temporarily. It does feel like you have “pushed back”. You haven’t, and the material that needs to be expelled is still there. But gases can leak out the more relaxed anus slowly under weaker peristalsis, or it will push out the fecal material with a gush when you let it all out.

But nothing goes back up past the sphincter to the large intestine, gas or solids, unless you are very sick. And nothing you can do will change the odour for the better. Of course, holding the gas in longer may act to increase … potency.


Here are two

from Salon and

From smellypoop.com yeah, I know, but YOU try and find serious pages discussing farts

Feel free to provide your own cites that held in farts stay in the rectum, or are leaked out unknowingly, instead of migrating back to the large intestine for eventual release.