It was social suicide: “I can’t burp!” yelped little Suzie at the College party. There was howling and nasty finger pointing, as the peeps at the shin-dig filled their glasses with beer and downed it in record time. Burping and belching erupted in a gas filled night of fun and debauchery. Poor little Suzie, was something wrong with her schooling that meant she couldn’t belch? Or was there something wrong with everyone else that was making gas rise from their bellies and out of their mouths?

 Why do we burp?

Burping or belching, scientifically called eructation, happens when swallowed air is released from your throat or stomach through your mouth. As the stomach expands to let food in, it relaxes the lower part of your oesophagus and this allows air to be sucked into your stomach. Once the lower part of your oesophagus relaxes it triggers your upper oesophagus to relax and expand too. This means that air gets vacuumed up the throat, and out of your mouth in a big ol’ BURRP!

So, there was nothing wrong with the people at the party, because swallowing air is perfectly normal when you eat, and burping is a normal way to release that gas. In fact, scientists reckon that around 30mL of air is ingested every time we swallow.

Why can’t Suzie burp?

After much scientific searching, I couldn’t find any papers describing people who can’t burp, or explaining why some people can’t do it. Now this is not to say that some people don’t have difficulty burping, it’s probably more the case that not being able to burp isn’t a big enough problem for biologists and medical doctors to spend some hard earned funding trying to solve the conundrum.

From first principles, it seems that if little Suzie can’t burp, a few things could be happening. Perhaps the food and way that Suzie eats means that she doesn’t swallow very much air as she eats. Or maybe her lower or upper oesophagus doesn’t naturally expand to such a great extent to let air in – so it doesn’t vacuum pump a burp out of her mouth.

What if I burp too much?

Funnily enough, the real problem in the scientific burping community related to burping is people who burp too much. Outside of a college frat party, excessive belching can be quite embarrassing. And indeed if you do find yourself in front of the queen with such a condition, you might want to get acquainted with the word: Aerophagia, which literally means to eat air.

Aerophagia describes an array of conditions related to eating air, including excessive belching, abdominal pain, bloating and abdominal distension. According to studies describing the condition, it’s somewhat common – “every gastroenterologist occasionally encounters patients who consult primarily because of excessive belching” says one paper. Aerophagic patients often find themselves frequently belching at times unrelated to meals.

Quite interestingly, the vast majority of these aerophagic belches come from air sucked into the oesophagus and expelled out immediately, before it reaches the stomach. These supragastric belches are different to most burps, which enter the stomach and then get burped out.

What would cause excess belching?

Other gas-related symptoms that form aerophagia, such as bloating and abdominal distension are commonly associated with gastrointestinal disorders, like the irritable bowel syndrome. But since the excessive loud burps of aerophagia come from air that doesn’t reach the stomach, it’s difficult to say whether gastrointestinal disorders are to blame for this condition.

Studies have shown that patients with aerophagia swallow the same amount of air as patients without the condition. This removes excess air in the throat as a possible cause. In fact, even the air bubble size of the gases are the same for aerophagic and non-aerophagic people. This has left scientists rather confused about the condition, and an expert’s best guess at this point is that excess burping is caused by the mind, not the body.  

There are a couple of reasons that researchers pinpoint psychological issues as a cause of aerophagia. For one, most patients don’t have the condition forever – in fact the median duration of symptoms is 24 months. Plus, in a large analysis of aerophagic patients there was a high prevalence of anxiety and depression. Repetitive belching has also been spotted in the initial representation of some neuro-psychiatric disorders.

 To study if belching was somehow related to the mind rather than the body researchers took 10 patients with excessive belching and distracted them to test if distraction reduced the number of burps the produced. Amazingly – it did! When patients were told that their burping was being measured, the frequency of belching was more than doubled.  But during the distraction period, when patients were asked to fill in questionnaires, the belching rate substantially decreased. Why stress and psychology might lead to excessive belching is currently unknown.

 So it seems that it’s not little Suzie at that frat party that we should be worried about. Suzie is doing just fine. It’s the stressed, confused Sammy, that hasn’t drunk any beer, and is belching loudly and frequently that is a cause for concern. And to this day, with all of our scientific knowledge, the cause for his excessive burping remains an anomaly.