What Is CPAP Aerophagia (Swallowing Air), and Does It Matter?

Aerophagia means swallowing air. On CPAP, researchers identify it by symptoms people report, such as bloating, belching and more flatulence [S1][S2]. ResMed's FAQ for clinicians says some people get bloating when they use a PAP device, “particularly when treatment first starts” [M1].

Studies define it by what people report, not by a test. A 2008 study counted any history of painful bloating, belching or flatulence related to CPAP use [S2]. A 2013 study counted anyone who noticed at least one of six changes after starting CPAP: more stomach noise, bloating (especially in the morning), less appetite in the morning, belching, more flatulence or more diarrhea [S1]. The authors of the 2008 study wrote that they had no objective measure of aerophagia or reflux [S2].

No. AirwayLab does not detect, measure or estimate aerophagia, and it has no chart or metric for it. Bloating, belching and gas are things you notice yourself, so you are the one who can report them to your clinician or sleep team.

There is no single reliable number, because the figure depends on how aerophagia is defined and who is asked.

• In the 2013 study, 130 of 259 sleep apnea patients (50.2%) reported at least one possible sign after starting CPAP [S1]. They had used CPAP at home and were back at a sleep lab for an overnight CPAP check, for reasons that included a routine pressure check and problems tolerating or using CPAP [S1]. A commentary on that study notes that the group may have included more people who struggled with CPAP, and that because some of the symptoms counted are not specific to aerophagia, the study may have overestimated how common it is [S3].
• A 2025 questionnaire study from Helsinki analysed 324 replies. It found that most people who reported aerophagia symptoms on CPAP already had those symptoms before they started CPAP, and its authors wrote that earlier figures “may be overestimated” [S4]. About a third of the people sent the questionnaire replied (32%), which the authors list as a limitation [S4].

In the 2013 study, reflux symptoms meant heartburn or acid coming back up [S1]. In that study, people with aerophagia symptoms more often reported reflux symptoms at least once a week (29% vs 10%) and reflux symptoms during sleep (9% vs 2%) [S1]. The 2008 study compared 22 CPAP users with aerophagia and 22 CPAP users without it, matched for age, gender and body mass index. More of the aerophagia group reported reflux symptoms (77.3% vs 36.4%), though reflux disease recorded by a doctor was not significantly more common [S2].

Both studies found a link. Neither shows what causes what. The 2013 authors wrote that their data “cannot directly answer the question” of which comes first, though they thought swallowed air leading to reflux was more likely than the other way round [S1]. Neither study measured reflux with a test [S1][S2].

Tell your sleep team or the clinician who prescribed your CPAP if:

• bloating, belching or gas bothers you
• it makes you want to use CPAP less, or stop. In the 2025 study, 3 of 324 people who replied (about 1%) said they had stopped CPAP because of stomach or gut symptoms [S4]
• you also get heartburn or acid coming back up, especially at night, because aerophagia symptoms and reflux symptoms during sleep went together in the 2013 study [S1]

You do not have to wait to be asked. A commentary on the 2013 study notes that most CPAP users do not openly mention aerophagia symptoms and clinicians may not specifically ask about them [S3]. The 2013 study's authors recommended that clinicians watch for aerophagia and reflux symptoms in patients on CPAP [S1].

Your clinician or sleep team can look at what is behind your symptoms. Any change to your therapy is their call, not something to work out from a web page.