What is a CPAP Machine and How Does It Work?

Medically reviewed by
 Dr. Nayantara Santhi

Dr. Nayantara Santhi

Dr. Nayantara Santhi holds an academic position at Northumbria University. After completing her Ph.D. at Northeastern University (Boston, MA), she joined the Division of Sleep Medicine at Harvard Medical School as a post-doctoral fellow to research how sleep and circadian rhythmicity influence our cognitive functioning.

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If you’ve been diagnosed with sleep apnea, your doctor may suggest using a CPAP machine during the night. Throughout this article, we explain what a CPAP machine is and how…

Last Updated On March 7th, 2023
What is a CPAP Machine and How Does It Work?

If you’ve been diagnosed with sleep apnea, your doctor may suggest using a CPAP machine during the night. Throughout this article, we explain what a CPAP machine is and how it works.

What is Sleep Apnea?

Sleep apnea (SA) interferes with your sleep. To better understand how a CPAP machine can prevent sleep disruptions, we describe the three different types of sleep apnea Verified Source Mayo Clinic Ranked #1 hospital by U.S. News & World Report and one of the most trusted medical institutions in the world. The staff is committed to integrated patient care, education, and research. View source below.

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  • Obstructive sleep apnea (OSA): Obstructive sleep apnea occurs when the muscles supporting the soft palate in the back of the throat relax. This response causes the airways to collapse and narrow. As the airways close, breathing becomes difficult, and oxygen levels in the blood decrease. The brain recognizes a lack of oxygen and wakes the sleeper up to breathe. Those with OSA typically wake 5 to 30 times every hour with a gasp, snort, or cough.
  • Central sleep apnea (CSA): Central sleep apnea occurs when the brain doesn’t send signals to the muscles that control breathing. When this communication becomes impaired, sleepers may stop breathing during sleep, causing them to wake up gasping for air.
  • Complex sleep apnea syndrome: Those with complex sleep apnea experience both obstructive sleep apnea and central sleep apnea.

What is a CPAP Machine and How Does it Work?

A CPAP (continuous positive airway pressure) machine provides relief from all three types of sleep apnea. This machine supplies a steady stream of air to the throat to keep the airways from collapsing as sleepers inhale. The continuous airflow makes breathing easier, so those with sleep apnea can find restful sleep.

A standard CPAP machine has a hose and an attached facemask, which is secured with a chin strap. A small water tank and filter work to power the device—similar to a humidifier. A CPAP machine produces air pressure that is strong enough to keep the airways open, but gentle enough not to interfere with sleep.

An NCPAP (nasal continuous positive airway pressure) machine is similar to a standard CPAP machine; however, it covers just the nose. Instead of a full face mask, the hose is attached to prongs that fit inside the nostrils—this is often called a nasal mask. Air pressure is then supplied through the mask to the nose to keep sleepers breathing comfortably throughout the night.

A BiPAP (bilevel positive airway pressure) machine works in much the same way as a CPAP and NCPAP machine, but a BiPAP machine automatically adjusts the air pressure as you sleep. A BiPAP machine increases pressure as sleepers inhale since inhalation is difficult for sleep apnea patients. However, it decreases air pressure during exhalation to keep the nose and throat from drying out.

Frequently Asked Questions

Which type of CPAP machine is right for you?

If your health care provider prescribes a CPAP machine, they will work with you to determine the best type of CPAP device. You may also have CPAP therapy to fine-tune the size of your CPAP mask, the pressure settings, and the best way to sleep while wearing the mask. In some cases, your doctor may recommend working with a sleep specialist or participating in an overnight sleep study to discover exactly what type of CPAP machine you need.

Does a CPAP give you oxygen?

A CPAP machine cannot increase the percentage of oxygen in the air. The air in the room contains the same amount of oxygen and other elements we usually breathe. However, a CPAP machine can improve the blood’s low oxygen levels by preventing breathing disruptions.

What are two benefits of a CPAP device?

CPAP machine

When used correctly and consistently, a CPAP device can reduce sleep disruptions, lower blood pressure, and reduce heart problems. This improves memory, mood, immune function, and muscle recovery.

When should a CPAP be used?

If you have sleep apnea and have been prescribed a CPAP machine by your doctor, you should use it every night. It is also a good idea to use the device when you are napping. Even if you are resting for 10 to 20 minutes, you may still experience disruptive apneas in this short time. A CPAP machine can prevent this and help you sleep peacefully.

What are the side effects of using a CPAP machine?

Using a CPAP machine can lead to a dry mouth, nose, and throat. In some cases, sleepers may also develop nasal congestion and skin and eye irritation. It can also be challenging to get comfortable with the mask on. However, untreated sleep apnea can lead to severe complications, including high blood pressure, stroke, heart disease, depression, and daytime drowsiness.


Dr. Nayantara Santhi says, “Sleep apnea is a prevalent and often undiagnosed condition. Because it causes sleep disturbances, sleep apnea leads to significant impairment in memory, mood and cognitive functioning. Treating it can go a long way in restoring good sleep and thereby health and well-being.”

If you suspect you have sleep apnea, talk to your doctor about treatment options. Ignoring this sleep disorder may lead to more nighttime disruptions and other medical complications. With your doctor’s help, you can discover which CPAP machine is right for you and start getting a good night’s sleep immediately.

About the author

Stacy Liman is a journalism graduate student and a freelance writer with a focus on mindfulness and content marketing. Stacy enjoys discovering new mattresses and connecting people with their perfect bed, but she more so enjoys understanding and writing about the science of sleep to help people get deeper, healthier rest.

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