The science of nasal breathing
Most of us breathe through our mouths far more than we realise. Here's a plain-language look at how nasal breathing differs, and what the published research does — and doesn't — show. Where the evidence is strong, we say so. Where it's limited, we say that too.
Your nose does a lot that your mouth can't: it warms, filters and humidifies the air, and adds nitric oxide from the sinuses. When the nose is blocked or the nostrils collapse, people tend to switch to mouth breathing, especially at night. Researchers have looked at how that switch relates to snoring, sleep, the mouth, exercise, feeling calm, pregnancy and, in children, development. Here's what they've found.
What your nose does that your mouth can’t
Here’s what nose breathing quietly does for your body, every single breath.
A natural nitric-oxide boost
Your sinuses release nitric oxide as you breathe in through your nose, a molecule that helps relax and widen blood vessels.
✦ Nitric oxide, on every nasal breath
A calmer nervous system
Slow nasal breaths gently engage the vagus nerve, nudging you out of fight-or-flight and into a steadier, rest-and-recover state.
✦ A calmer, rest-and-recover state
Built-in air filtering
Your nose warms, humidifies and filters air before it ever reaches your lungs, trapping dust, allergens and bacteria on the way in.
✦ Cleaner air to your lungs
Better CO₂ balance
Gentler nasal breathing helps keep carbon dioxide at a steadier level, supporting a more even, efficient breathing rhythm.
✦ Steadier, more efficient breathing
Deeper, fuller breaths
Breathing through your nose encourages slow, diaphragm-led breaths, fuller and more relaxed than quick, shallow mouth breaths.
✦ Fuller, diaphragm-led breaths
Calmer, steadier nights
Quiet, steady nasal breathing overnight supports a more settled night, less tossing, turning and waking through the small hours.
✦ Calmer, steadier nights
Mouth breathing and snoring
Well studiedSleeping with the mouth open tends to narrow the airway and make snoring more likely. Studies that compare the oral and nasal breathing routes during sleep have found that breathing through the mouth raises upper-airway resistance, which is closely tied to snoring. When a blocked or narrow nose is part of the problem, keeping it open supports quieter breathing.
References
- Fitzpatrick MF et al. Effect of nasal or oral breathing route on upper airway resistance during sleep. Eur Respir J, 2003.
- Meurice JC et al. Effects of mouth opening on upper airway collapsibility in normal sleeping subjects. Am J Respir Crit Care Med, 1996.
Steadier breathing, steadier rest
Well studiedFragmented, open-mouth sleep means more time in a lighter, more alert state and less in calm, restorative rest. The same research on breathing route during sleep links open-mouth breathing with higher airway resistance and more disturbed nights. Easier nasal breathing supports quieter, more settled rest, though it isn't a treatment for any medical sleep condition.
References
- Fitzpatrick MF et al. Effect of nasal or oral breathing route on upper airway resistance during sleep. Eur Respir J, 2003.
- Meurice JC et al. Effects of mouth opening on upper airway collapsibility in normal sleeping subjects. Am J Respir Crit Care Med, 1996.
Dry mouth overnight
Well documentedBreathing through an open mouth overnight dries up saliva, the mouth's natural defence for the teeth and gums. Research links habitual mouth breathing with reduced saliva and poorer oral-health markers. Nasal breathing helps keep the mouth more naturally moist.
References
- Mummolo S et al. Salivary markers and microbial flora in mouth breathing children. BioMed Research International, 2018.
- Wagaiyu EG, Ashley FP. Mouthbreathing, lip seal and on-going gingival inflammation. J Clin Periodontol, 1991.
Breathing efficiency when you train
Emerging evidenceMouth-only breathing tends to be quicker and shallower, a less efficient way to exchange air. Some studies link nasal breathing with better breathing efficiency and lower perceived effort. Importantly, the evidence does not show that it boosts raw power or maximal oxygen uptake (VO₂max), so this is about steadier, more comfortable breathing, not a performance upgrade.
References
- Eser et al. Nasal vs oral breathing and ventilatory efficiency during exercise. Frontiers in Physiology, 2024.
- Recinto et al. Effects of nasal or oral breathing on anaerobic power output and metabolic responses. Int J Exercise Science, 2017.
Why steady sleep matters
Background contextPoor-quality, broken sleep keeps the body in a more alert state and means less time in calm, restorative rest. Over the long term, disrupted night-time breathing has been associated with higher blood pressure. It's worth being clear about the evidence here: the strong blood-pressure research below studied people with diagnosed obstructive sleep apnoea using CPAP therapy, not mouth breathing, and not a nasal product. It's included as general background on sleep and the heart, nothing more.
References
- Martínez-García MA et al. Effect of CPAP on blood pressure in patients with OSA and resistant hypertension (HIPARCO). JAMA, 2013.
- Becker HF et al. Effect of nasal CPAP treatment on blood pressure in patients with OSA. Circulation, 2003.
Breathing and growing faces
Strong associationIn children especially, long-term mouth breathing has been associated in research with differences in how the jaw and face develop, including narrower jaws and longer face shapes. This is one of the better-studied associations in the field. It's general information, not a product claim. Airlift is not a children's product or a treatment, and any concern about a child's breathing or development should go to a healthcare professional.
References
- Zhao Z et al. Effects of mouth breathing on facial skeletal development in children: a systematic review and meta-analysis. BMC Oral Health, 2021.
- Zheng W et al. Facial morphological characteristics of mouth breathers vs nasal breathers: a meta-analysis. Experimental and Therapeutic Medicine, 2020.
Slow breathing and a calmer state
Background contextSlow, steady breathing is at the heart of many relaxation and breathing techniques. Research links slow breathing with measurable shifts in the body's stress response, including heart-rate variability and self-reported calm. This is general information about slow, nasal breathing, not about Airlift, and it is not a treatment for anxiety or any mental-health condition.
References
- Zaccaro A et al. How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience, 2018.
- Ma X et al. The effect of diaphragmatic breathing on attention, negative affect and stress in healthy adults. Frontiers in Psychology, 2017.
A stuffy nose in pregnancy
Well documentedA blocked, stuffy nose is a common and well-documented part of pregnancy, often called pregnancy rhinitis, and it can disturb sleep. Because it's driven by hormonal changes, it usually settles after birth. A drug-free nasal dilator can make nose-breathing easier without sprays or medication, but this is general information, not medical advice, so check with your midwife or doctor.
References
- Ellegård EK. Pregnancy rhinitis. Immunology and Allergy Clinics of North America, 2006.
- Ellegård E, Karlsson G. Nasal congestion during pregnancy. Clinical Otolaryngology, 1999.
A simpler way to keep the nose open
Airlift is a reusable magnetic clip and skin-safe stickers that gently hold your nostrils open to encourage nasal breathing — no straps, and nothing going up your nose.
This page is general information, not medical advice, and not a claim about what Airlift can do for you. Speak to a qualified healthcare professional about any concerns.
References
The prevalence figures on our homepage draw on the following peer-reviewed studies.
- Madronio MR et al. Older individuals have increased oro-nasal breathing during sleep. Eur Respir J, 2004.
- Young T et al. Chronic nasal congestion at night is a risk factor for snoring in a population-based cohort study. Arch Intern Med, 2001.
- Ohayon MM et al. Snoring and breathing pauses during sleep: telephone interview survey of a United Kingdom population sample. BMJ, 1997.