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The Science Behind How a CPAP Machine Works

The Science Behind How a CPAP Machine Works

The Science Behind How a CPAP Machine Works

Millions of Americans have sleep apnea, a disorder in which one’s breathing is interrupted while they sleep. These interruptions can lead to episodes of waking throughout the night and impair one’s ability to get restorative sleep.

Fortunately, a continuous positive airway pressure (CPAP) machine might offer relief. CPAP machines are the most prescribed devices to treat sleep apnea, and they can profoundly improve quality of life. Find out more by looking at the science behind how a CPAP machine works.

The Three Types of Sleep Apnea

Different factors can cause sleep apnea. Understanding these causes will help you understand how a CPAP machine helps. Here are the 3 types of sleep apnea:

1. Obstructive Sleep Apnea

The most common type of sleep apnea is obstructive sleep apnea. This occurs when the muscles that support the soft palate, uvula, tonsils, and side walls of the throat and the tongue relax. This relaxation creates an obstruction in the airway and prevents the lungs from getting enough oxygen.

2. Central Sleep Apnea

If you have central sleep apnea, your nervous system doesn’t send the proper signals to the muscles that control breathing. You won’t breathe for a short period of time, and you might awaken with shortness of breath or have a difficult time falling or staying asleep.

3. Complex Sleep Apnea

The third type is complex sleep apnea, also known as treatment-emergent central sleep apnea. This is a combination of obstructive sleep apnea and central sleep apnea.

How a CPAP Machine Functions

Doctors commonly prescribe CPAP machines to treat sleep apnea. To put it briefly, these devices deliver pressurized air, which keeps the airway open. The pressurized air ensures that one breathes continuously as they sleep.

Here’s a more detailed explanation. The CPAP machine consists of 3 basic components: a motor, a tube, and a mask. You’ll place the motor, which is a small, quiet compressor, on your bedside table. It pulls in air from the room and pressurizes it to a level set by your sleep specialist. Your sleep specialist calibrates your device to deliver air from 4 centimeters of water pressure (CWP) to a maximum of 25 CWP. For most people, the best CPAP pressure is between 6 and 14 CWP. The pressure level is key to the science behind how a CPAP machine works. If you find you need to adjust the pressure level, your sleep specialist can help you make the necessary changes.

You can use a CPAP humidifier to warm the pressurized air, which helps you avoid a dry mouth and nose. The air passes through a filter before entering a flexible tube that delivers the purified air into your mask. Headgear made of soft, stretchable material keeps the mask in position. You might have a mask that goes over your nose (nasal mask) or over your nose and mouth (full-face mask).

When choosing a mask, you’ll consider your favorite sleeping positions, your body type, and other variables such as facial hair. For example, a nasal pillow mask can also have soft prongs that fit into your nostrils, which works well if you have a lot of facial hair. Choosing the right mask will help you sleep comfortably with your device.


CPAP machines provide air at one preset pressure level and require manual adjustments if you need to change the pressure. However, another type of CPAP machine, called an automatic positive airflow pressure (APAP), can automatically adjust air pressure. APAP machines can detect a collapse of the airway and increase the pressure of the air to reopen it. They can also test if a lower pressure is appropriate and, if so, lower the pressure.


A bilevel positive airway pressure (BiPAP) machine is a type of CPAP machine that delivers air at 2 different pressure settings. One setting helps the user inhale, and a lower setting makes it easier for the user to exhale. BiPAP machines typically treat central sleep apnea because they can prompt breathing.

Benefits of Using a CPAP Machine

Without a CPAP device, relaxed muscles can partially or completely obstruct your airway. By constantly flowing pressurized air into the upper airway, the CPAP machine creates a cushion of air that prevents anything from collapsing or shifting. This air also reduces snoring vibrations.

The machine might also relieve swelling in your nose and clear out mucus from your airways. Your sleep quality will improve because your sleep is no longer fragmented. Because of this, the CPAP machine can reduce your daytime sleepiness and lower your risk of having a heart attack, stroke, or other cardiovascular event.

Common Issues

You might have to make some adjustments before finding the right mask for you. For example, if you wear a full-face or nasal mask and have air leaking from the bridge of your nose, you might have a poorly fitting mask. You can get a mask in a different size or style to address this.

Another common issue you might encounter is a dry mouth. Using a humidifier will help with this. Your equipment provider or sleep specialist can help you adjust the tube’s temperature or your humidifier’s settings so that you can receive air at a comfortable humidity level.

If you keep waking up or snoring loudly, your pressure is probably too low. Check to make sure your device isn’t leaking any air. If necessary, increase your pressure level settings. Too-low pressure can cause you to gasp for air during the night, causing bloating, gas, discomfort, and belching. Similarly, if the air pressure setting is too high, you can end up swallowing air. Overly high pressure can also cause discomfort in your mouth, nose, or airways, such as a burning sensation in the nose and throat.

If you’re uncomfortable in any way while using the CPAP machine, talk to your health-care provider. A board-certified sleep specialist can review your sleep study and monitor your apnea-hypopnea index (AHI). The AHI indicates how many times you stop breathing during the course of an hour of sleep. With your AHI, your specialist can make any necessary adjustments.

Get Your CPAP Equipment

CPAPnation is your trusted CPAP equipment supplier. We carry a large inventory of nasal, nasal pillow, and full-face masks from top brands in the industry. We also offer other supplies for your CPAP machine, such as cushions and tubing. CPAPnation makes it easy for you to get and customize your CPAP equipment for your needs. Browse our selection and get a good night’s rest.

The Science Behind How a CPAP Machine Works


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