The Science of Mouth Breathing

Let’s be real.

Most of us don’t spend much time thinking about how we breathe at night.

You go to bed, close your eyes, and wake up eight hours later. Hopefully you feel refreshed. But maybe you notice a dry mouth. Maybe your partner mentions you’ve been snoring lightly. Or maybe you just feel less rested than you should.

It turns out the way you breathe while you sleep might be part of the picture.

This isn’t about diagnosing or treating anything. It’s about looking at what research says about mouth breathing versus nasal breathing, and why more people are experimenting with nighttime lip taping as part of their wellness routines.

GIF via GIPHY/ The Simpsons / Used for illustrative/commentary purposes.

How common is mouth breathing at night?

It’s more common than you might expect.

One study found that nearly everyone with sleep-disordered breathing—about 97%—showed signs of mouth breathing during sleep. Even among healthy sleepers, around one in four did the same.¹

And when a national survey asked adults about their own habits, over half said they sometimes or often breathe through their mouth.² That means open-mouth breathing is happening quietly in bedrooms everywhere, often without the person even realising.


GIF via GIPHY/ from Disney’s “Frozen” (2013). Used for illustrative/commentary purposes. 

Why your mouth feels dry in the morning

When you breathe through your mouth, you skip your nose’s natural humidifier. Air comes in cooler and drier, which can leave your tongue or throat feeling parched by morning.

Some research has linked mouth breathing with a higher likelihood of waking up with dryness and oral discomfort.³ Saliva production naturally slows down during sleep, and if you’re already breathing through your mouth, you’re losing even more moisture. With less saliva, bacteria can build up more easily overnight. Not the best start to your day.


GIF via GIPHY

The quiet work your nose does while you sleep

Your nose isn’t just there to let air in. It:

• Filters dust and airborne particles

• Warms the air so it feels comfortable to breathe

• Adds humidity to keep your airways from drying out

When the mouth becomes the main breathing route, that process is skipped. Over time, research suggests this can be linked to airway dryness or even a feeling of nasal congestion.⁴

How it becomes a habit without you noticing

For some, mouth breathing starts as a quick fix—maybe from a stuffy nose during a cold or seasonal allergies. But over time, it can become the default, even after the original cause is gone.

Studies in craniofacial development show that habitual mouth breathing can change tongue posture, muscle activity, and the way your jaw rests.⁵ People often only notice when discomfort creeps in, or when someone else points it out.


GIF via GIPHY/ from A Diary of a Wimpy Kid (2010). Used for illustrative/commentary purposes.

Why awareness matters

Comfortable breathing often starts with the nose. Air that’s filtered, warmed, and humidified tends to feel gentler on the throat and lungs. Mouth breathing, on the other hand, can bring in cooler, drier air that some people find irritating over time.⁴

Becoming more aware of your breathing habits—especially at night—can be the first step toward small adjustments that support comfort.

Sleep quality and daytime energy

If mouth breathing leads to disrupted sleep, maybe from dryness or from shifting positions more often, you might notice the effects the next day.

Research has shown that fragmented sleep can influence how refreshed people feel in the morning, and in some cases, even their energy or focus during the day.⁷ Everyone’s experience is different, but it’s an area scientists continue to explore.

Why people are talking about mouth taping

In wellness circles, nasal breathing and mouth taping have been getting more attention in recent years. Surveys show that over 60% of adults in some regions identify as occasional or habitual mouth breathers.²

For many, experimenting with gentle habits to encourage nasal breathing at night isn’t about treating a medical condition. It’s about curiosity, comfort, and seeing if it helps them wake up feeling better.

A note before you try anything

This page is here to inform, not to diagnose, treat, or prevent any medical condition. All information is based on publicly available research and is shared in a non-therapeutic context.

If you have ongoing sleep issues, breathing difficulties, or any medical concerns, it’s always best to speak with a qualified healthcare professional before making changes to your nighttime routine.

References
¹ Su et al. (2023), Biomedical Journal
² Breathe Right Survey, U.S. Adults, 2015
³ Lin et al. (2022), Frontiers in Public Health
⁴ Kukwa et al. (2018), Int. J. Pediatr. Otorhinolaryngol.
⁵ Jefferson, Y. (2010), “Mouth breathing: adverse effects on facial growth, health, academics, and behavior.” General Dentistry
⁶ Abreu et al. (2008), “Mouth breathing and forward head posture: effects on respiratory biomechanics and muscle activity.” Journal of Human Growth and Development
⁷ Beebe, D.W. (2011), “Cognitive, behavioral, and functional consequences of inadequate sleep in children and adolescents.” Pediatric Clinics of North America