If you use a continuous positive airway pressure (CPAP) machine for obstructive sleep apnea (OSA), you may breathe better at night. But you may also have dry mouth in the morning.

The good news: There are ways to avoid getting dry mouth from a CPAP machine. Keep reading to learn how.

CPAP therapy delivers a steady flow of air into your airway. For some people, the treatment causes the mouth to open during sleep, says Shannon Sullivan, MD, a sleep specialist and clinical professor of pulmonary medicine at Stanford University School of Medicine in California. When your mouth is open and exposed to air, it’s more likely to dry out.

Some people with OSA may already breathe through their mouths, partly because OSA affects the upper airway, and the CPAP might exacerbate this. “It can augment part of the abnormal breathing route or symptoms related to it,” says Dr. Sullivan.

It’s also possible that the CPAP mask doesn’t fit or seal properly, and air is escaping through your mouth and drying it out in the process, says Monica Mallampalli, PhD, president and CEO of the Alliance of Sleep Apnea Partners in Ellicott City, Maryland.

It can be. In fact, it’s one of the big reasons people stop using a CPAP machine, says Sullivan. But if you don’t use CPAP because your dry mouth is so uncomfortable, “The negative health impact is that … you’re letting the disease go untreated,” she says.

The first step is to talk to an expert, such as the healthcare provider who diagnosed you with OSA or the specialist who provided the CPAP machine, says Dr. Mallampalli.

A professional can help you figure out why you’re experiencing dry mouth and suggest some changes. They’ll likely start by assessing the data logged by the CPAP device. Most machines collect data on your breathing, such as air leak, which can help a professional determine if the mask fits properly and in a way that limits mouth breathing and dry mouth, says Sullivan.

If you decide to continue CPAP therapy, there are a few steps you can take to reduce the risk of dry mouth:

• Use the humidifier on the CPAP machine. “The heated humidifier and heated tubing can make an enormous difference for the overall sense of dryness,” says Sullivan. Adding distilled water to the compartment may be a little annoying at first, but it’s better than having dry mouth.
  
• Adjust the settings. If you’re already using the humidifier on the CPAP device, try adjusting the heat and humidity settings to see if you can get a little more comfortable.

• Try a new mask. If you’re using a nasal mask, your provider might recommend a mask that covers your mouth as well, which may help limit some of the dryness. You could also consider trying a chin strap that attaches to the CPAP and helps hold your mouth closed. “But it’s not for everyone,” says Sullivan.
• Stay hydrated. “A lot of people are in a chronically dehydrated state, and you’re going to notice dryness and thirst more,” says Sullivan. To stay hydrated, sip water regularly throughout the day, she says.

• Using a CPAP machine for obstructive sleep apnea may make you more likely to breathe through your mouth during the night, which can lead to dry mouth.
• Dry mouth is uncomfortable — a major reason people don’t adhere to CPAP treatment — and a risk factor for certain oral health concerns.
• To prevent dry mouth, talk to your healthcare provider. You may need to adjust how the mask fits, try a chin strap, stay better hydrated, or consider other forms of treatment. It’s possible another underlying condition could be contributing to dry mouth also.