CPAP is normally prescribed for people with obstructive sleep apnea (OSA), which is caused by a physical blockage in the throat that hinders airflow in the breathing passages. People with OSA wake up choking or gasping for air due to episodes known as apneas and hypopneas.

Apnea refers to complete air obstruction, whereas hypopnea is partial air obstruction, but both can interfere with healthy sleep. Apneas and hypopneas both last at least 10 seconds, and hundreds of these episodes may occur during a single night. People with OSA are also prone to chronic snoring.

The most common risk factor for OSA is obesity, which accounts for roughly 60% of moderate to severe OSA diagnoses. Sleeping on your back can exacerbate the condition, as this allows the tongue to fall back into the throat and further obstruct breathing. Consuming alcohol before bed can also worsen OSA symptoms, since it can cause the throat muscles to relax. Other common causes of OSA include:

  • Facial irregularities: OSA can occur when someone has a large tongue, an irregular shape on the roof of their mouth, or a disproportionately small lower jaw compared with their upper jaw.
  • Large neck: A collar size of at least 17 inches for men and 16 inches for women has been linked to OSA.
  • Enlarged tonsils or adenoids: This is a leading cause of OSA in children. Both the tonsils and adenoids can be surgically removed.

Roughly 4% of men and 2% of women in the U.S. meet the diagnostic criteria for OSA. About 1% to 5% of children have OSA. The prevalence of the condition increases with age.

CPAP therapy is sometimes prescribed for people with central sleep apnea (CSA), a condition that occurs when the brain is unable to send signals to muscles that regulate breathing. However, the effectiveness of CPAP for treating this type of sleep apnea has not been proven.

How Does CPAP Therapy Work?

A doctor’s prescription is required to purchase the machine and face mask, but anyone can obtain the hose and other CPAP accessories. Following a sleep apnea diagnosis, your doctor will prescribe an air pressure level based on the severity of your symptoms.

The CPAP machine features a fan that draws in air and a filter to separate contaminants. Some machines also feature humidifiers to provide extra moisture when delivering air through the hose. Humidifiers can alleviate some of the uncomfortable side effects of CPAP therapy, such as dry mouth and sore throat, but this component is not required.

Before turning on the CPAP machine, check to see if the hose is properly connected to both the machine and your face mask. Also, make sure the mask is secure. Most CPAP masks have elastic straps that allow comfortable fitting regardless of your head’s size or shape. People with sleep apnea should use their CPAP equipment whenever they sleep. This includes not only in-home use each night, but also for napping or while traveling.

Adjusting to CPAP therapy can be challenging. Most doctors caution that the first few nights of using a CPAP machine can result in poor sleep. If you experience ongoing discomfort, this may necessitate a change to your CPAP prescription. The pressure level settings on a CPAP machine cannot be manually changed. After your doctor has updated the prescription, you will need to arrange for the machine’s manufacturer to adjust the settings.

CPAP Cleaning Guidelines

Regular maintenance is essential for keeping the equipment hygienic. If you use CPAP therapy, you’ll need to do the following:

  • Clean the CPAP mask and tubing every day. Most hoses can be washed in warm, soapy water. The mask should be disassembled, and each part should be washed separately with mild soap. Air-dry these components and make sure they are moisture-free before reassembling them.
  • If your machine includes a humidifier, sanitize it using a solution of warm water and white vinegar. The humidifier should soak for several minutes.
  • Clean or replace the air filter as needed. Disposable filters need to be replaced every couple of weeks, while reusable filters should be cleaned on a weekly or biweekly basis and replaced every three months or so.

These guidelines apply to most CPAP equipment sold today. Be sure to check the owner’s manual for specific cleaning instructions before using your CPAP machine for the first time.

Some companies sell devices designed to clean CPAP machines using ozone gas or ultraviolet light. However, the Food and Drug Administration has issued a warning about these devices. People who have used these types of CPAP cleaners report asthma attacks, headaches, and breathing problems. These devices are not approved by the FDA.

Types of CPAP Masks

CPAP masks are sold separately from CPAP machines. Like the machines, CPAP masks require a prescription. Your doctor can recommend which type of mask is best based on your sleep apnea symptoms. The most common types of masks are listed in detail below.

Type of Mask
Best for...

Full Face

A full seal over the nose and mouth, covering the lower half of the face

  • Back sleepers
  • People who primarily breathe through their mouths while sleeping
  • CPAP users who need high pressure settings
  • Bulky design
  • Not always conducive to side sleeping


A small seal over the nasal bridge and upper lip that delivers air to the nostrils, but not the mouth

  • Side sleepers
  • People who primarily breathe through their noses
  • Those who need high pressure settings
  • Largely ineffective for those who primarily breathe through their mouth
  • Potential for nasal blockage

Nasal Pillow

A seal over each nostril that provides airflow to the nose without covering any part of the mouth

  • People who find other CPAP masks too cumbersome
  • Side sleepers
  • Users who need low to moderate pressure settings
  • Not conducive to high pressure levels
  • Potential for nasal irritation


A seal over the mouth without delivering air to the nostrils

  • People with allergies or nasal blockages
  • Those who primarily breathe through their mouths
  • Less effective for people who breathe through their noses
  • High potential for air to escape

Total Face

Complete coverage of the face, resulting in airflow for the nose and mouth

  • People who have not found other mask types effective
  • Back sleepers
  • Heavy and bulky compared with other mask types

Prices for CPAP masks vary by type, with full face, nasal pillow, and total face masks being the most expensive. That said, most masks are available for $250 or less.


CPAP is often used as a catchall term for any type of PAP therapy for sleep apnea. However, CPAP machines differ from BiPAP and APAP machines in terms of pressure delivery.

  • CPAP: The air pressure level remains constant throughout the breathing cycle.
  • BiPAP: The air pressure increases during inhalation and decreases during exhalation, but each pressure level remains the same.
  • APAP: The machine automatically adjusts pressure levels during inhalation and exhalation based on the user’s breathing patterns.

Some people have a hard time breathing properly with a single fixed pressure level. These individuals are good candidates for BiPAP or APAP therapy. Devices for these types of PAP therapy tend to be more expensive than CPAP devices, but they may be a worthwhile investment if your sleep quality suffers during CPAP therapy. Talk to your doctor before purchasing your device, and continuously check in with them to discuss how your therapy is progressing.

Alternatives to PAP Therapy

CPAP, BiPAP, and APAP therapies are widely prescribed for people with OSA — and, to a lesser extent, CSA — but these are not the only treatment options for those living with sleep apnea. If you have been diagnosed with OSA, alternatives to PAP therapy include:

  • Dental devices: A mandibular advancement device (MAD) is a type of mouthguard that physically moves the lower jaw forward to increase airflow through the breathing passages. MADs can be effective anti-snoring tools, and may also reduce apnea and hypopnea episodes. Tongue-retaining devices (TRDs), which hold the tongue in place, are also widely available. Although prescriptions are rarely needed for either type of device, a sleep specialist may recommend a custom-fitted device in consultation with your dentist.
  • Wireless implants: A treatment called Inspire Sleep Apnea Innovation has received FDA approval. It involves the insertion of an electronic device under the skin in the chest and chin areas through a surgical procedure. The device is designed to transmit signals to muscles around the tongue that regulate breathing. Many insurance providers cover the procedure, but out-of-pocket costs may be a dealbreaker.
  • Surgery: If CPAP therapy has proven ineffective, surgery may be a viable sleep apnea treatment — though this should be considered a last resort. Depending on the person’s diagnosis, surgery may be used to remove excess tissue, change the facial structure, or widen the opening of breathing passages. For children with sleep apnea, removal of the tonsils, adenoids, or both, may be the most effective option.
  • Lifestyle changes: Some people can reduce their sleep apnea symptoms by losing weight, switching their sleep position to the side or stomach, or abstaining from alcoholic beverages before bedtime.


+13 Sources

  1. MedlinePlus: National Library of Medicine (US). (2021, August 20). Positive airway pressure treatment. Retrieved April 20, 2022, from
  2. Pinto, V.L., & Sharma, S. (2021, July 31). Continuous positive airway pressure. In StatPearls. StatPearls Publishing. Retrieved April 20, 2022, from
  3. MedlinePlus: National Library of Medicine (US). (2021, June 3). Obstructive sleep apnea – adults. Retrieved April 20, 2022, from
  4. Özer, T., Selçuk, A., Yılmaz, Z., Voyvoda, N., Çam, İ., Özel, H.E., Özdoğan, F., Esen, E., Genç, G. & Genç, S. (2018). The role of upper airway morphology in apnea versus hypopnea predominant obstructive sleep apnea patients: An exploratory study. The British Journal of Radiology, 91(1087), Article e20170322.
  5. American Academy of Sleep Medicine. (2014). The International Classification of Sleep Disorders – Third Edition (ICSD-3). Darien, IL.
  6. Slowik, J.M., & Collen, J.F. (2022, February 10). Obstructive sleep apnea. In StatPearls. StatPearls Publishing. Retrieved April 20, 2022, from
  7. Carter, K. A., Hathaway, N. E., & Lettieri, C. F. (2014). Common sleep disorders in children. American Family Physician, 89(5), 368–377.
  8. MedlinePlus: National Library of Medicine (US). (2021, July 12). Central sleep apnea. Retrieved April 20, 2022, from
  9. Strohl, K.P. (2020, September). Central sleep apnea. Merck Manual Professional Version. Retrieved April 20, 2022, from
  10. National Heart, Lung, and Blood Institute. (2022, March 24). CPAP. Retrieved April 20, 2022, from
  11. U.S. Food and Drug Administration. (2020, February 27). CPAP machine cleaning: Ozone, UV light products are not FDA approved.
  12. Patil, S.P., Ayappa, I.A., Caples, S.M., Kimoff, R.J., Patel, S.R., & Harrod, C.G. (2019). Treatment of adult obstructive sleep apnea with positive airway pressure: An American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment. Journal of Clinical Sleep Medicine, 15(2), 301–334.
  13. U.S. Food and Drug Administration. (2020, June 29). Inspire upper airway stimulation – P130008/S039.

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