9 signs you breathe through your mouth at night

You can't watch yourself sleep, but your body leaves clues by morning. A dry mouth, drool on the pillow, a scratchy throat, snoring and stale breath are the most common signs that you spent part of the night breathing through your mouth. Here are nine to look for, and what to do if several sound familiar.

It helps to know the baseline. In a 2003 study of 10 healthy adults with clear noses, only about 4% of the air they breathed in during sleep went through the mouth. So regular mouth breathing at night usually means something is nudging you off the default, most often a nose that doesn't let enough air through.

Signs you'll notice in the morning

You wake up with a dry mouth

Waking up with a dry mouth is the classic sign of mouth breathing at night. The NHS lists breathing through your mouth at night as one of the main causes of a dry mouth, whether from a blocked nose or simply sleeping with your mouth open. Air that skips the nose dries your tongue and gums for hours while your body makes less saliva. Why do I wake up with a dry mouth? covers the other causes.

There's drool on your pillow

Drool on your pillow sounds like the opposite of a dry mouth, but both come from the same open mouth. Cleveland Clinic lists drooling when asleep as a common symptom of mouth breathing, and notes that when you sleep with your mouth open, saliva either dries out or escapes as drool.

Your throat is scratchy or your voice is hoarse

Cleveland Clinic explains that breathing through your nose keeps moisture in your mouth and throat, and that mouth breathing is one of the reasons people wake up with a sore throat. It also lists hoarseness among the common symptoms. If it eases within an hour of getting up, a night of dry air over your throat is the likely cause.

Your breath is worse than it should be

Cleveland Clinic says morning breath happens when your mouth dries out overnight and bacteria multiply, and names mouth breathing as something that makes it worse. Bad breath is also on its list of common mouth breathing symptoms.

Your lips are dry or cracked

The National Institute of Dental and Craniofacial Research lists cracked lips among the symptoms of dry mouth. It also lists a dry feeling in the throat and a burning or itchy feeling in the mouth. Lips that feel chapped every morning, even in humid weather, are another hint that air has been moving across them all night.

Signs during the night and the day

You snore, or someone tells you that you do

Snoring is on Cleveland Clinic's list of common mouth breathing symptoms, and the Sleep Foundation explains that breathing through the mouth can make the soft tissues in the throat vibrate. Not all snoring comes from an open mouth, but if a partner says your mouth hangs open while you snore, that's a strong clue.

Your nose feels blocked when you lie down

Cleveland Clinic says most people breathe through their mouth because they can't get enough air through their nose, from congestion, allergies, a deviated septum, enlarged turbinates or nasal polyps. Lying flat adds to it: a 2022 meta-analysis of nine studies found that nasal resistance rises when you lie down. If your nose feels tight at bedtime, your mouth is probably taking over later.

You wake up tired after a full night

Cleveland Clinic lists feeling tired all the time as a common symptom of mouth breathing and says it can affect your sleep. Tiredness has many causes, though, and heavy daytime sleepiness is also a warning sign of sleep apnea, so read the section below before putting it down to mouth breathing.

You can't comfortably keep your mouth closed

Not being able to comfortably keep your mouth closed is a sign doctors check with a simple test. Cleveland Clinic describes a lip seal test, which checks whether you can breathe with your mouth closed. It also describes a mirror test, where a mirror held under the nose fogs up if you're breathing through it, and a water test, where you hold water in your mouth so you have to breathe through your nose. Try the same idea with our two-minute nose test. If breathing through your nose with your lips together feels like hard work, your nose is the place to start.

When it could be more than mouth breathing

A dry mouth on waking can also be a sign of obstructive sleep apnea. In a 2020 study from Spain, it affected 45% of people with sleep apnea compared with 20.4% of healthy people. The American Academy of Sleep Medicine lists snoring, choking or gasping during sleep, and daytime sleepiness among the warning signs, along with morning headaches, unrefreshing sleep and waking during the night to pee. If your signs come with any of those, see a doctor before trying fixes at home. Snoring vs. sleep apnea explains the difference.

Children are different too. Cleveland Clinic says mouth breathing in children can affect growth, behaviour and face shape, so a child who breathes through the mouth should see a pediatrician rather than try tape or strips.

What should you do if these signs sound familiar?

If these signs sound familiar, start by noticing how often they happen, since two or three of them on most mornings is a fair hint that you mouth breathe at night. If you share a bed, ask your partner to glance at you once or twice during the night. Cleveland Clinic suggests talking to a healthcare provider if you have symptoms like bad breath or drool on your pillow, so they can find out why air isn't getting through your nose.

Start with your nose. Clear what you can before bed, and if your nose feels narrow, try a nasal strip. A 2016 meta-analysis noted that nasal dilators have been shown to improve nasal breathing, although they didn't improve sleep apnea measures. How nasal strips work explains the mechanics.

If your nose is clear and your mouth still drifts open, mouth tape is a simple way to keep your lips together. The Sleep Foundation describes it as a gentle reminder that encourages nasal breathing, while noting the research is still limited and that it isn't for anyone with a blocked nose or untreated sleep apnea. Start with our first-week guide, and see mouth tape vs. nasal strips if you're deciding between them.

Our pick: the Titan Sleep System (paid partner)

Since most mouth breathers need help on both ends, the set we recommend is the Titan Sleep System, which pairs TitanAir Nasal Strips with Titan Bamboo Silk Mouth Tape. Titan says the strips are drug-free with flexible spring-loaded bands, worn just above the flare of the nostrils, and that the tape is bamboo silk with an adhesive made to grip through stubble and beards. Titan says both are third-party tested and certified PFAS-free, and both come with a 30-night guarantee.

For more, browse our nasal breathing articles.

Read next

• Why do I breathe through my mouth at night?
• 11 ways to breathe through your nose at night
• Nasal breathing vs. mouth breathing

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.