The most common signs your CPAP pressure is too high are stomach bloating and gas from swallowing air, difficulty exhaling against the airflow, and frequent mask leaks. Most people need a pressure between 8 and 10 cm H₂O, though the therapeutic range runs from 4 to 20. If your pressure sits well above that average and you’re experiencing discomfort, it’s worth investigating.
Stomach Bloating and Excessive Gas
The single most telling sign of too-high pressure is aerophagia, which simply means you’re swallowing air pushed into your throat by the machine. Instead of all the pressurized air going into your lungs, some of it travels down your esophagus and into your stomach. The result is a bloated, distended belly, frequent burping, and more gas than usual. Cleveland Clinic notes that people with aerophagia can belch up to 120 times an hour, compared to a normal rate of about 10. If you’re waking up with a visibly swollen stomach or cramping that wasn’t there before you started CPAP, pressure is the first thing to look at.
Difficulty Breathing Out
CPAP delivers a constant stream of air to keep your airway open. When the pressure is set correctly, you barely notice it while exhaling. When it’s too high, breathing out starts to feel like blowing against a wall. You may catch yourself tensing your abdominal muscles to push air out, or you might wake up feeling short of breath even though air is flowing freely. Some people describe it as fighting the machine.
This sensation is different from the mild adjustment period most new users go through in the first week or two. If you’ve been using your machine for more than a few weeks and exhaling still feels like effort, the pressure is likely higher than it needs to be.
Frequent Mask Leaks
Higher pressure pushes harder against the seal of your mask. If you’re getting air blowing into your eyes, hearing a whistling sound, or seeing “large leak” alerts on your machine’s data readout, excessive pressure could be the cause. Mask leaks have several possible explanations (a worn cushion, a poor-fitting frame, sleeping on your side), but air pressure that’s too high increases the likelihood of leaks regardless of mask fit. If you’ve already ruled out the obvious culprits and your mask still won’t seal, your pressure setting deserves a closer look.
Leaks also create a secondary problem. When air escapes around the mask, it flushes out carbon dioxide from the space between your face and the cushion. That shift in gas balance can actually trigger pauses in breathing, which your machine may then interpret as apnea events and ramp up pressure even further, making leaks worse in a frustrating cycle.
New Breathing Pauses That Weren’t There Before
This one is harder to notice on your own, but it shows up clearly in your machine’s nightly data. When CPAP pressure is set too high, some people develop a condition called treatment-emergent central sleep apnea. Unlike obstructive apnea (where your airway physically collapses), central apnea means your brain temporarily stops sending the signal to breathe. The excessive pressure stretches receptors in your lungs that trigger a reflex to pause breathing.
If your AHI (the number of breathing interruptions per hour your machine records) was improving but has started climbing again, or if your data shows a new category of “central” events, that’s a strong indicator your pressure has crept too high. An AHI under 5 is considered normal for someone on treatment. A sudden, unexplained rise over several days or weeks is worth flagging to your sleep specialist.
Waking Up More, Not Less
CPAP is supposed to reduce nighttime awakenings, not increase them. If you’re waking up multiple times gasping, pulling your mask off in your sleep, or just feeling restless through the night despite good mask fit, overpressure may be disrupting your sleep architecture. Some of these awakenings happen because of the central apnea events described above. Others happen simply because the sensation of too much air triggers a startle response during lighter stages of sleep.
What Your Machine Data Can Tell You
Most modern CPAP machines track several data points overnight, and reviewing them is the fastest way to confirm a pressure problem. Look for three things:
- AHI trend: A number under 5 is the goal. If it was low and is now rising, something has changed. A rising AHI paired with central events specifically points toward overpressure.
- Leak rate: Your machine reports this in liters per minute. Consistently high leak numbers, especially if your mask fits well, suggest the pressure is overwhelming the seal.
- Pressure graph: If you use an auto-adjusting machine (APAP), check what pressures it’s actually delivering overnight. An APAP set to a range of 5 to 20 cm H₂O might be spending most of the night at 15 or higher. That tells you something different than a machine hovering at 9.
Free software like OSCAR can pull detailed data from most machines and display it in graphs that make these patterns easy to spot.
Pressure Relief Settings Worth Trying
Before requesting a full pressure change, there’s a comfort feature built into most machines that can help. It’s called expiratory pressure relief (EPR on ResMed machines, C-Flex or A-Flex on Philips). When turned on, it drops the air pressure slightly each time you breathe out, then brings it back up when you inhale. You still get the full therapeutic pressure to keep your airway open, but exhaling feels much more natural.
EPR has three levels (1, 2, or 3), with each level reducing the pressure by about 1 cm H₂O during exhalation. At the maximum setting of 3, you’d feel 3 cm H₂O less pressure every time you breathe out. The machine won’t let pressure drop below 4 cm H₂O regardless of your EPR setting. If you’re on a pressure of 12 and exhaling feels difficult, turning EPR to 3 means you’d exhale against a pressure of 9, which can make a noticeable difference. This is particularly helpful for people who need high pressures to treat their apnea but struggle with the sensation of blowing against strong airflow.
Getting Your Pressure Adjusted
Your CPAP pressure is a prescription, so changing it involves your sleep specialist or equipment provider. If you use a fixed-pressure CPAP, the number was set based on your original sleep study or titration test. Bodies change over time (weight loss, aging, alcohol use, sleep position shifts), and the pressure that worked a year ago may not be right today. Bring your machine data to your appointment so your provider can see the patterns rather than relying on symptoms alone.
If you use an auto-adjusting APAP machine, your provider can narrow the pressure range. For example, if your machine is set to 5 to 20 and it’s consistently delivering 16 to 18, your provider might lower the upper limit. Alternatively, if the machine is overshooting and causing central events, switching to a bilevel (BPAP) machine may help. Bilevel machines deliver a higher pressure when you inhale and a lower pressure when you exhale, which is a more aggressive version of what EPR does and can resolve both the discomfort and the central apnea issue.