CPAP therapy is the standard treatment for obstructive sleep apnea (OSA), a condition where the airway repeatedly collapses during sleep. The machine delivers a steady stream of pressurized air through a mask, acting as an air splint to keep the upper airway open and prevent blockages. This mechanism eliminates the breathing pauses characteristic of sleep apnea and should reduce or eliminate snoring, which is the sound of vibrating tissue. However, residual snoring can still occur even with CPAP use. When snoring persists, it signals that the therapy is not working optimally and requires troubleshooting.
Why Residual Snoring Occurs Despite CPAP Use
CPAP therapy prevents the complete or partial collapse of the airway that defines apnea events. Snoring is the vibration of the soft palate and surrounding tissues, and the air pressure may not be sufficient to eliminate all vibration, especially if the pressure setting is too low. Pressure inadequacy is a frequent cause of residual snoring, as the prescribed setting may not be strong enough to maintain a fully open airway throughout all stages of sleep or in all sleeping positions.
Mask leaks are another significant cause of persistent noise and vibration. When air escapes through a poor seal, the intended therapeutic pressure is lost, allowing the airway to partially collapse and resulting in snoring. The escaping air can also cause turbulence or vibrate the tissues near the leak, which can mimic or exacerbate the snoring sound.
If a patient uses a nasal mask but breathes through their mouth during sleep, the pressurized air bypasses the intended pathway. This mouth breathing allows the soft palate to vibrate freely, leading directly to snoring and potentially causing a dry mouth upon waking. Nasal congestion or obstruction, such as from allergies, a cold, or a deviated septum, can force mouth-breathing, which reduces the effectiveness of the nasal CPAP pressure and promotes snoring.
Differentiating Snoring from CPAP Noise
Users and their partners often struggle to determine if the disruptive noise is true physiological snoring or simply a sound produced by the machine or mask itself. True snoring is a deep, guttural, vibratory sound originating in the throat and soft palate. This sound is intermittent and corresponds with the user’s breathing cycle, often becoming louder during deep inhalation.
Sounds produced by the CPAP equipment are more mechanical or turbulent. For instance, air escaping from a poor mask seal can create a high-pitched whooshing or whistling sound. This noise is turbulence, not tissue vibration, and clearly indicates a leak that needs to be addressed.
The CPAP machine’s motor produces a low, constant hum or mechanical vibration whenever the device is powered on. The exhalation ports on the mask, which release the used air, create a steady, whooshing noise as the pressurized air vents away from the face. Distinguishing these consistent, non-vibratory equipment sounds from the intermittent, deep rumble of true snoring is helpful for accurate troubleshooting.
Immediate Troubleshooting and Adjustments
A mask leak is a primary cause of lost pressure and residual snoring, so performing a systematic mask fit check is the most direct user adjustment. This involves ensuring the mask cushion is centered and seated correctly, then gently adjusting the tension of the headgear straps. The mask must be snug enough to prevent leaks when the machine is running, but not so tight that it causes painful pressure points or skin indentations.
If mouth breathing is the source of snoring, users of nasal masks or nasal pillows can use a chin strap to keep the jaw closed during sleep. Another option is switching to a full-face mask that covers both the nose and mouth, ensuring pressurized air delivery regardless of the breathing route.
Sleeping on the back often worsens snoring because gravity increases the likelihood of the tongue and soft palate falling backward into the airway. Changing sleep position to lie on the side can reduce this gravitational effect and may eliminate minor snoring. For individuals with frequent nasal congestion, using a heated humidifier on the CPAP machine can moisten the air and help keep nasal passages open. Saline nasal sprays can also be used before bed to clear obstructions caused by allergies or colds.
When Residual Snoring Indicates a Deeper Issue
If immediate troubleshooting efforts fail and snoring persists, the core CPAP therapy may be insufficient, requiring professional intervention. The most important indicator of a problem is continued excessive daytime sleepiness, even if snoring has lessened. This symptom suggests that sleep apnea events are still occurring.
Users should check their CPAP machine’s data, which reports the Apnea-Hypopnea Index (AHI). The AHI is the average number of breathing pauses or shallow breathing events per hour; a score above five indicates inadequate treatment. If the AHI remains elevated despite consistent use, the prescribed pressure is likely too low to adequately splint the airway.
The user must contact their sleep physician to discuss a pressure re-evaluation. Pressure requirements can change over time due to weight fluctuation, aging, or progression of the underlying condition. The physician may recommend an in-lab or at-home re-titration study to determine a higher, more effective pressure setting. Persistent, loud snoring could also point to a secondary anatomical issue, such as a deviated septum or enlarged tonsils, requiring consultation with an ear, nose, and throat specialist.