10 CPAP Machine Side Effects and How to Prevent Them

CPAP therapy is one of the primary treatments for sleep apnea. The treatment involves a machine to supply a steady stream of pressurized air through a mask worn when sleeping. The steady flow of air stops the upper airways from blocking and prevents the breathing difficulties associated with sleep apnea.

However, there can be some mild side effects from using CPAP which are outlined below.

Dry Mouth

People who tend to breathe through their mouth or who sleep with their mouths open can find they wake up with a dry mouth. This is caused by dry, pressurized air being exhaled from the mouth and can happen regardless of the type of mask worn, although it is usually more common when wearing a full-face mask. 

How to Prevent: You can moisten the air supplied by your machine using a humidifier, softening the air you exhale. If you use a nasal mask or a nasal pillow mask, then a chin strap will help keep your mouth closed when sleeping.

Dry Eyes

Air escaping from your mask and blowing in to your eyes can cause dry eyes.

How to Prevent: Check to make sure your mask fits correctly and if it does not, have it adjusted or replaced with one that does. Check your straps too, as headgear which is either too loose or too tight can also mean the seal on the mask cushion is not secure, leading to air leaking out.

Skin Irritation

An ill-fitting mask can also irritate your skin. Another source of skin irritation is the sweat, skin oils and dead skin cells which can collect on the mask. This can result in a buildup of bacteria and can cause irritation, rashes, sores and other skin issues.

How to Prevent: Regular cleaning of your mask will prevent bacteria and germ buildup. It is also recommended you replace the cushion of your mask frequently as it can tear with use, providing places for bacteria to gather. A mask liner can also prevent a build-up of sweat and skin oils.

Difficulty Exhaling

Some users can find CPAP difficult to adjust to initially. The continuous flow of pressurized air can lead to difficulties in exhaling.

How to Prevent: Consult with your doctor about changing the pressure settings on your machine. Your doctor may also recommend an APAP machine which monitors your breathing and adjusts the pressure settings accordingly, or a BiPAP machine, where a lower pressure can be set for exhalation.


Another reason users can struggle to adjust to wearing a CPAP mask overnight is due to a feeling of claustrophobia. This can be more so with those wearing a full-face mask.

How to Prevent: Gradually get used to your mask by wearing it while you are awake. Start without the machine switched off and then, when feeling more comfortable, with the machine on. There are full-face masks designed with more minimal facial contact, but otherwise a nasal mask or nasal pillow mask could also be a good option.

Nasal Congestion

This is one of the more common side effects of the treatment, and can range from a runny or blocked nose, as well as nose bleeds. Nasal congestion is caused by the flow of dry pressurized air.

How to Prevent: You can moisten the air using a humidifier to make it easier on the sinuses, while a heated humidifier will also gently heat the air you breathe. A nasal saline spray can also offer relief.


An ill-fitting mask can feel uncomfortable, which becomes a potential hurdle to sticking with your sleep apnea treatment plan. The mask may even be painful when worn overnight.

How to Prevent: Having a correctly fitting mask is crucial for the effectiveness of the treatment and reducing sleep apnea symptoms. Work with your doctor to find a mask which fits you properly, or to adjust the existing mask if necessary. Masks come in different sizes, and you should not settle for an ill-fitting mask.


The pressure of the air supplied by your machine may cause headaches, while headaches may also result from nasal congestion resulting from CPAP.

How to Prevent: If you experience headaches you should consult with your doctor, who may be able to reduce the pressure setting on your machine to relieve the headaches. If the headaches result from nasal congestion, using a heated humidifier to moisten and warm the air may also help relieve this issue.

Shortness of Breath

Although the pressure settings on a CPAP machine will allow for enough air to be inhaled as you sleep, problems exhaling against the pressure can lead to shortness of breath for some people. 

How to Prevent: If you are experiencing shortness of breath you should consult with your doctor, who may reduce the exhalation pressure setting on your machine. It is vital that you don’t try to adjust any settings by yourself. Your doctor may also recommend using an APAP or BiPAP machine, which will either automatically adjust the pressure settings according to your breathing, or provide the option for a lower pressure setting when exhaling to replicate a more natural breathing rhythm.


If you are finding it difficult to exhale against the pressure of the air supplied by your machine, the air can begin to enter the esophagus. This process is known as aerophagia, and tends to occur with higher pressure settings. The result can be uncomfortable levels of gas, stomach pain, burping and feeling bloated.

How to Prevent: Consult with your doctor about adjusting the pressure settings on your machine.

Final Thoughts

Such side effects are rarely dangerous, but they can deter people from persevering with their treatment plan. While CPAP can take some adjusting to, it is important to stick with the treatment to reduce the symptoms of sleep apnea, which left untreated can increase the risk of serious health complications.

Talk to your doctor about these problems, so you’re better able to continue your CPAP treatment comfortably and safely.