How to Prevent CPAP Dry Mouth

CPAP machines are used to treat obstructive sleep apnea (OSA), a sleep disorder that can lead to gaps in breathing during sleep due to an airway restriction A CPAP delivers a constant stream of pressurized air through a hose and mask, which helps breathing by keeping the upper airway open. While CPAP machines can help alleviate OSA symptoms and improve the user’s quality of life, this therapy can come with unwanted side effects, including dry mouth – or xerostomia. 

Dry mouth is a reported CPAP side effect¹ and a reason people may discontinue CPAP therapy². If you’re experiencing dry mouth while using your CPAP machine, don’t despair – we’ll explain what can cause it, ways to prevent it, and what you should do if symptoms persist. 

Why Do CPAP Machines Cause Dry Mouth?

There are several reasons why you might experience dry mouth while using your CPAP machine, including a poorly-fitted mask, the flow of pressurized air decreasing saliva production, mouth breathing, and a lack of humidification.

• Decreased saliva – Pressurized air flowing through the nasal cavity can affect saliva production³ because the nose and mouth are connected via the nasopharynx (the top part of your throat). Decreased saliva production can leave you with a dry, uncomfortable mouth.
• Mouth breathing – Breathing through the mouth can dry up the saliva⁴ that usually keeps your mouth moist. However, the constant flow of air from a CPAP can exacerbate this. CPAP users who breathe through their nose but sleep with their mouth open may also experience dry mouth due to pressurized air escaping through the mouth and drying it out⁵.
• Dry air – Your CPAP draws in air from the environment, so unless a humidifier is used in the machine or room, those living in low-humidity climates can receive a pressurized stream of dry air, further zapping moisture from the mouth. 

Other Causes of Dry Mouth

Dry mouth during CPAP therapy may not necessarily be caused by your PAP device; there are a host of reasons why you might be experiencing decreased saliva, and it may be helpful to rule them out first.

• Medication – Dry mouth is a side effect of some medications⁶, both prescription and over-the-counter, resulting from the medicine decreasing saliva production. Medication that often causes dry mouth includes those used to treat depression, anxiety, high blood pressure, and Parkinson’s.⁶ It can also be an issue with antihistamines, decongestants, and certain pain relievers.⁶ 
• Illnesses – Certain health conditions can increase dry mouth⁷, including diabetes, HIV/AIDS, stroke, autoimmune diseases, and Alzheimer’s. 
• Dehydration – Dehydration occurs when the body loses more water than it’s taking in. Water is crucial for the body to function properly, as it’s made of up to 65 percent water⁸. Feeling thirsty is a sign that you’re already dehydrated. In addition to dry mouth, dehydration can cause tiredness, headaches, and constipation⁹.
• Salivary gland issues – Sialothiasis¹⁰ is a rare condition in which stones form in the salivary glands and block the flow of saliva. This causes pain, swelling, and dry mouth. The condition is more prevalent among males aged 30 to 60 years old.¹¹ Swollen salivary glands, or sialadenitis¹¹, can also cause a decrease in saliva, as well as pain while eating, swelling, and fever. Some causes of sialadenitis are dehydration, poor oral hygiene, infection, and certain medications.¹¹
• Tobacco – Research shows that smoking cigarettes can increase the risk of dry mouth¹². Additionally, some recent research¹³ found that e-cigarette users are even more likely than traditional cigarette smokers to experience dry mouth.
• Marijuana – Smoking cannabis is linked to a decrease in saliva production¹⁴, which can lead to dry mouth. It’s thought that tetrahydrocannabinol (THC), which is the main compound in cannabis, can negatively impact salivary glands.¹⁴
• Stress/anxiety – Several studies¹⁵ show a link between stress and anxiety, and a significant reduction in salivary flow​​.​​ The sympathetic and parasympathetic nervous systems control the salivary glands¹⁶. The sympathetic nervous system is activated when you’re stressed, triggering the body’s “fight or flight” response¹⁷, which diverts energy to body parts that may help you escape danger, including slowing down digestion. During this process, saliva becomes thicker to prohibit the first part of the digestive process, which can cause the mouth to dry out.

Tips to Prevent CPAP Dry Mouth 

Humidification 

Using a humidifier with your CPAP adds moisture to the air you breathe, which can reduce the risk of dry mouth. With a humidifier, the air is moistened when it passes over a chamber of distilled water before being delivered through the mask. Humidifiers are either built into the machine or attached externally. Another way to add moisture is to use heated tubing with your CPAP machine. 

Explore: Best Humidifiers for The Bedroom

Breathe Through Your Nose

Breathing through your nose instead of your mouth could help alleviate dryness since mouth breathing dries up saliva, which can cause dry mouth.⁵ For those who already breathe through your nose but keep their mouth open when they sleep, which could also cause dryness, a CPAP chin strap could help. The chin strap gently keeps the mouth closed¹⁸, and it can lessen unintentional air leaks. 

Relieve Nasal Congestion

Nasal congestion can cause you to breathe through your mouth, which means relieving the congestion could help. You can try using a saline spray¹⁹ to lubricate the nose and get rid of mucus. If the congestion is caused by allergies, a pharmacist can advise you on the most appropriate remedies.

Try a Different Style of Mask 

Research shows that dry mouth is more common among users of oronasal masks²⁰ than those who use nasal masks or nasal pillows. This may be because oronasal masks appear to leak more than nasal masks²¹, which can cause dry mouth. Therefore, it might be worth speaking to your doctor about trying out a nasal-type mask instead. 

Find the Best Nasal CPAP Masks.

Stay Hydrated 

Not consuming enough water can lead to dehydration and dry mouth. In the U.S. it’s recommended that men consume 3.7 liters of fluids a day²² and that women consume 2.7 liters. This includes water, other beverages, and water consumed through food. However, some people will require more or less than this recommendation; for example, if you’re unwell, live in a hot or humid climate, or exercise a lot, you may need to drink more. You’ll know you’re drinking enough when you seldom feel thirsty, and your urine is light yellow or colorless.

Tips to Prevent CPAP Dry Mouth 

How to Treat Dry Mouth Caused by Your CPAP Machine 

If your dry mouth persists throughout the day, you can grab a few quick fixes from the store. One option is to chew sugar-free gum, which can help to stimulate salivary flow²³. The National Institute of Dental and Craniofacial Research suggests sucking on sugarless hard candies²⁴, ideally citrus, cinnamon, or mint flavors. You should also avoid tobacco and alcohol, and limit your intake of caffeinated drinks as these can all dry out the mouth. 

Over-the-counter remedies²⁵ , including gels or sprays, can act as saliva substitutes. These should contain either xylitol, carboxymethylcellulose, or hydroxyethyl cellulose. You can also buy mouthwash designed for dry mouth; again, look for ones containing xylitol. Sipping water throughout the day or sucking on ice chips²⁶ are also helpful options.

What to Do If Your Dry Mouth from CPAP Persists 

If you have exhausted your options and are still experiencing dry mouth, you should talk to your healthcare provider. They can help rule out other causes of your dry mouth, and if CPAP is the reason why, they may offer a different solution for treating your sleep apnea that doesn’t involve CPAP therapy.