In humans, belching can be caused by normal eating processes, or as a side effect of other medical conditions. When belching is excessive it may be classed as a belching disorder, one of thegastroduodenal disorders.[2] Belching is a frequent symptom ofgastroesophageal reflux disease (GERD) but this is distinct from a belching disorder.[3]
There is a range of levels of social acceptance for burping: within certain contexts and cultures, burping is acceptable. In some cultures and situations it may even be perceived as humorous, while in others it is seen as impolite or even offensive and therefore unacceptable. An infant often accumulates gas when feeding, and this needs to be vented by way of burping. To burp the baby is the common expression.[4]
Thebelch reflex is responsible for the ability to belch. Most of the air that is swallowed during eating and drinking cannot be absorbed in the gastrointestinal tract and is vented by way of belching. Swallowed air is allowed to rise from the stomach into the esophagus, through a relaxedlower esophageal sphincter. The gaseous distention of the esophagus triggers the belch reflex in the relaxation and opening of theupper esophageal sphincter to release the air into the pharynx.[6]
The expelled gas is mainly a mixture of the main components of atmospheric air -oxygen andnitrogen.[7] Burps can be caused by drinking beverages such asbeer andcarbonated drinks, and in these cases, the expelled gas is mainlycarbon dioxide.
Chewing gum, sucking onhard candy, talking while eating or drinking, or while smoking, can also cause more air to be swallowed and therefore increased belching. Also swallowing air may in some people be anervous habit.[8]
Inmicrogravity environments, burping is frequently associated withregurgitation, known aswet burping. With reduced gravity, the stomach contents are more likely to rise up into the esophagus when thegastroesophageal sphincter is relaxed, along with the expelled air.[12]
Belching, when excessive, can be due to either of twobelching disorders,excessive supragastric belching orexcessive gastric belching, two types ofgastroduodenal disorders.[1] A belching disorder is also termed as adisorder of gut–brain interaction (DGBI).[13]
Supragastric occurs above the stomach in theesophagus, and is classed as voluntary.[14] In supragastric belching the reflux episodes are mainly non-acidic making the use ofproton pump inhibitors that reduce stomach acidity, non-effective.[14] This type of belching disorder is often linked to anxiety, and is classed as abehavioral disorder as isrumination syndrome, another gastroduodenal disorder.[14][15]
Gastric belching arises from the stomach itself, and is classed as involuntary.[14] When gas is accumulated in thestomach it collects in thecardia the part nearest to thelower esophageal sphincter (LES). The increased volume stimulates stretch receptors in the wall of the stomach that initiates avagovagal reflex that temporarily relaxes the LES, known as atransient LES relaxation/TLESR, to allow air to move into the esophagus.
Both types of belching disorder may triggerreflux.[15]
SomeSouth Asian cultures view burping as acceptable in particular situations. For example, a burping guest can be a sign to the host that the meal satisfied them and they are full.[22]
InJapan, burping during a meal is considered bad manners.[23] Burping during a meal is also considered unacceptable in Western cultures, such asNorth America andEurope.[22]
An infant being burped against an adult's shoulder
Babies are likely to accumulate gas in the stomach while feeding and experience considerable discomfort (and agitation) until assisted. Burping an infant involves placing the child in a position conducive to gas expulsion (for example against the adult's shoulder, with the infant's stomach resting on the adult's chest) and then lightly patting the lower back. Because burping can causevomiting, a "burp cloth" or "burp pad" is sometimes employed on the shoulder to protect clothing.[4]
TheGuinness World Record for the loudest burp was 112.4dB, set by Neville Sharp fromDarwin, Australia in 2021.[24] This is approximately as loud as ajet engine at 100 m (330 ft).[25] The record was previously held by Paul Hunn, who held the record for 12 years.[26]
It is possible to voluntarily induce burping through swallowing air and then expelling it, and by manipulation of thevocal tract produce burped speech. While this is often employed as a means of entertainment or competition, it can also act as an alternative means ofvocalisation for people who have undergone alaryngectomy, with the burp replacing laryngealphonation. This is known asesophageal speech.[27]
Despite virtually no scientific research on the subject, small online communities exist for burping as asexual fetish.[28] Online, people of anysexual orientation anecdotally report some attraction to burping, with what appears to be psychological or behavioural overlaps with other sexual fetishes includingbody inflation,feedism,vorarephilia, andfarting fetishes.[29] Anecdotally, the 'loudness' aspect appears to be an important element to burp fetishists. Despite being a rather uncommon fetish,[30] it continues to follow a general well-known pattern of sexual behaviour where hearing influences sexual arousal and response, noting that "it is the noise made rather than the action itself that appears to be what is sexualized and/or interpreted by the fetishist as sexually pleasurable and arousing".[29]
One reason why cows burp so much is that they are often fed foods that their digestive systems cannot fully process, such ascorn andsoy. Some farmers have reduced burping in their cows by feeding themalfalfa andflaxseed, which are closer to the grasses that they had eaten in the wild before they were domesticated.[35]
There is no documented evidence that birds burp, thoughornithologists believe that there is nothing which physiologically prevents them from doing so. However, since themicrobiota of birds do not include the same set of gas-producing bacteria that mammals have to aid in digestion, gas hardly builds up in thegastrointestinal tracts of birds.[36]
^Cormier, René E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.),"Abdominal Gas",Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.), Butterworths,ISBN0-409-90077-X,PMID21250257{{citation}}: CS1 maint: work parameter with ISBN (link)
^abSawada, A; Fujiwara, Y (2024). "Belching Disorders and Rumination Syndrome: A Literature Review".Digestion.105 (1):18–25.doi:10.1159/000534092.PMID37844547.
