Thirdly, the volume of flatus produced by patients with irritable bowel syndrome who have pain and abdominal distension would be tolerated in normal subjects without any complaints of pain. Patients who complain of bloating frequently can be shown to have objective increases in abdominal girth, often increased throughout the day and then resolving during sleep. The increase in girth combined with the fact that the total volume of flatus is not increased led to studies aiming to image the distribution of intestinal gas in patients with bloating. They found that gas was not distributed normally in these patients: there was segmental gas pooling and focal distension. In conclusion, abdominal distension, pain and bloating symptoms are the result of abnormal intestinal gas dynamics rather than increased flatus production. Excessive volume
The normal range of volumes of flatus in normal individuals varies hugely (476–1,491 mL/24 h). All intestinal gas is either swallowed environmental air, present intrinsically in foods and beverages, or the result of gut fermentation. Swallowing small amounts of air occurs while eating and drinking. This is emitted from the mouth by eructation (burping) and is normal. Excessive swallowing of environmental air is called aerophagia, and has been shown in a few case reports to be responsible for increased flatus volume. This is, however, considered a rare cause of increased flatus volume. Gases contained in food and beverages are likewise emitted largely through eructation, e.g., carbonated beverages. Endogenously produced intestinal gases make up 74 percent of flatus in normal subjects.
"Spinraza access by country". TreatSMA. 18 October 2018. Retrieved 2019-05-28.