Continuous Positive Airway Pressure (CPAP) therapy is a common treatment for obstructive sleep apnea. This device delivers a steady stream of pressurized air through a mask to keep the user’s airway open during sleep. While highly effective, the pressurized airflow can sometimes lead to uncomfortable side effects, including nausea. This queasiness is typically a symptom of how the body manages the pressurized air, often stemming from issues with pressure management or equipment fit. Understanding the root cause of this stomach discomfort provides actionable steps toward relief and helps ensure continued adherence to therapy.
How CPAP Use Leads to Stomach Discomfort
The primary mechanism linking CPAP use to gastrointestinal distress is aerophagia, the excessive swallowing of air. CPAP machines direct pressurized air into the lungs, but if the pressure is too high, this air can inadvertently be diverted. The air bypasses the larynx and enters the esophagus, the tube connecting the throat to the stomach. Once the air passes the lower esophageal sphincter, it becomes trapped in the stomach or intestines, causing a buildup of gas. This accumulation leads to common aerophagia symptoms, such as bloating, abdominal distention, and belching. The resulting feeling of excessive fullness and pressure in the abdomen can then manifest as nausea.
Adjustments to Pressure and Equipment
Addressing air swallowing involves adjusting the mechanical and physical aspects of the therapy. The first adjustment is the machine’s pressure settings, which should always be done in consultation with a healthcare provider. If the prescribed pressure is too high, the excess force can overwhelm the airway and push air into the esophagus. Switching to an auto-adjusting positive airway pressure (APAP) device can also help, as it provides the lowest effective pressure throughout the night, reducing excessive air delivery.
Comfort Features
Modern CPAP devices include comfort features designed to mitigate the feeling of high pressure. The “ramp” feature begins therapy at a lower pressure and gradually increases it over a set time until the prescribed therapeutic pressure is reached. Another element is Expiratory Pressure Relief (EPR), which lowers the pressure only during exhalation, making it easier to breathe out against the airflow. Utilizing EPR can reduce the air resistance that might otherwise cause a user to unconsciously swallow air.
Mask Fit and Position
Equipment issues, particularly mask fit, can also contribute to aerophagia. A poor mask seal causes air leaks, prompting the machine to increase pressure to compensate for the loss, which exacerbates air swallowing. Ensuring the mask is the correct size and fit minimizes leaks and stabilizes the airflow. Changing the sleeping position by elevating the head of the bed using a wedge pillow can also help. This incline uses gravity to discourage air from entering the stomach and keeps the esophagus aligned.
When Nausea Requires Medical Attention
If nausea persists despite successfully troubleshooting CPAP equipment and optimizing pressure settings, the cause may be unrelated to the sleep therapy device. Consult a physician to rule out other potential health conditions. Nausea accompanied by vomiting, severe abdominal pain, or significant unexplained weight loss requires immediate medical evaluation, as these symptoms are not typical of CPAP-related aerophagia.
Gastroesophageal Reflux Disease (GERD) is a common condition that causes nausea and may be worsened by CPAP pressure changes, especially if the esophageal valve is weak. Other non-CPAP causes for persistent nausea include certain medications, inner ear disorders affecting balance, or underlying digestive issues. If a sleep specialist cannot resolve the issue through equipment adjustments, a referral to a gastroenterologist may be necessary to identify and treat the separate cause of the distress.