Nasal Breathing vs Mouth Breathing: Which Is Better?

Quick answer: for rest, sleep and light to moderate exercise, nasal breathing is better than mouth breathing. Your nose filters, warms and humidifies the air, adds nitric oxide made in your sinuses, and sets a slower, deeper breathing rhythm. Mouth breathing skips all of that and is linked to dry mouth, snoring and a more acidic mouth overnight.

Most of us never think about how we breathe. You take around 20,000 breaths a day, so the route that air takes adds up. This guide explains what your nose does that your mouth cannot, what the research shows, and how to make nasal breathing your default.

What is nasal breathing?

Nasal breathing means breathing in and out through your nose with your lips closed. On the way in, air passes over nasal hairs, a sticky mucus layer and the turbinates (curled ridges of tissue that add surface area). By the time it reaches the back of the throat, cold, dry outside air has been warmed to around 30 °C and brought close to 90% relative humidity. Dust, pollen and many microbes are caught before they get anywhere near your lungs.

Your nose also adds something your mouth cannot: nitric oxide. Swedish researchers showed in 1995 that the lining of the paranasal sinuses produces nitric oxide continuously and in high concentrations (Lundberg et al., Nature Medicine). When you breathe through your nose, that nitric oxide travels down into your lungs with every breath.

Why is nasal breathing better than mouth breathing?

Here is how the two routes compare side by side.

Does nasal breathing increase oxygen uptake?

Yes. Nasal breathing boosts oxygen uptake by 30 to 40% compared with mouth breathing. Two things drive this. First, the nose adds resistance, which slows each breath and gives your lungs more time to exchange gases. Second, nitric oxide from the sinuses helps open blood vessels in the lungs. In a study published in Acta Physiologica Scandinavica (Lundberg et al., 1996), blood oxygen levels rose when people breathed through the nose, and the effect was linked to that inhaled nitric oxide.

What does nitric oxide do?

Nitric oxide is a signalling molecule your body uses to relax and widen blood vessels. In the sinuses it also has an antimicrobial role, which helps keep that space clean. Breathing through your nose is the only way to bring this home-made nitric oxide into your lungs. Mouth breathing sends air straight past it.

What happens when you breathe through your mouth?

Occasional mouth breathing, during a sprint or with a cold, is normal. Habitual mouth breathing, especially at night, is where problems build up:

• Dry mouth and bad breath. Air flowing over the tongue and gums all night dries out saliva, which normally rinses away bacteria.
• A more acidic mouth. A 2016 study in the Journal of Oral Rehabilitation found the mouth averaged a pH of about 6.6 during sleep with mouth breathing, compared with about 7.0 with nose breathing, and at times dropped well below the 5.5 level where tooth enamel starts to soften.
• Snoring. An open mouth lets the jaw and tongue drop back, which narrows the throat and makes soft tissue vibrate.
• Lighter, choppier sleep. Waking with a dry throat or getting up to drink water breaks up your night.
• Faster, shallower breathing. Mouth breathing tends to use the upper chest instead of the diaphragm, which keeps the body in a more alert state.

Why do people mouth breathe?

Usually because breathing through the nose feels like hard work. The narrowest point of the whole airway is inside the nose, at the nasal valve, just behind the nostrils. According to a 2025 review in Frontiers in Surgery, this small area accounts for roughly half to two thirds of the total resistance to airflow inside the nose. A cold, allergies, a naturally narrow nose or sleeping position can tip the balance, and the mouth falls open as a shortcut. Once it becomes a habit, many people mouth breathe even when their nose is clear.

How can you switch to nasal breathing?

1. Notice it. Check a few times a day: are your lips closed, teeth slightly apart, tongue resting on the roof of your mouth? That is the nasal breathing position.
2. Breathe low and slow. Put a hand on your belly and take slow breaths through your nose so the belly moves first. A few minutes a day builds the habit.
3. Keep your nose clear. Rinse with saline when you are congested and keep your bedroom from getting too dry.
4. Open the nasal valve. If your nose feels narrow, a nasal strip lifts the sides of the nose and widens the valve, so nose breathing takes less effort. STRIPAIR nasal strips are drug-free and made for nightly use and training.
5. Use your nose during easy exercise. Walks, warm-ups and easy runs are a good place to practise. Our guide to nasal breathing for running and workouts explains how to build up.
6. Protect your nights. Sleep is where most mouth breathing happens. See how to stop snoring naturally and why you wake up with a dry mouth.

When is mouth breathing okay?

At maximum effort, like a sprint finish or a heavy set, your body needs more air than the nose can move, and breathing through the mouth is normal. The same goes for a heavy cold. The goal is not to never open your mouth. It is to make the nose your default at rest, during sleep and in easy to moderate exercise.

Frequently asked questions

Is nasal breathing really better than mouth breathing?
For rest, sleep and light to moderate exercise, yes. Your nose filters, warms and humidifies the air, adds nitric oxide from the sinuses and slows your breathing down. Mouth breathing skips those steps.

How much more oxygen do you get from nasal breathing?
Nasal breathing boosts oxygen uptake by 30 to 40% compared with mouth breathing, helped by slower breaths and nitric oxide from the sinuses.

Is it bad to sleep with your mouth open?
Sleeping with your mouth open is linked to dry mouth, bad breath, snoring and a more acidic mouth overnight. If it happens every night, it is worth working on nasal breathing.

Can nasal strips help me breathe through my nose?
Yes. A nasal strip lifts the sides of the nose and widens the nasal valve, the narrowest part of the airway, so breathing through your nose takes less effort. You can try both editions with the STRIPAIR Dual Pack.

How long does it take to become a nasal breather?
Most people notice a difference within a few weeks of daily practice. Start with rest and easy activity, then extend it to sleep and harder training.

Sources

• Lundberg JO et al. High nitric oxide production in human paranasal sinuses. Nature Medicine, 1995. PubMed
• Lundberg JO et al. Inhalation of nasally derived nitric oxide modulates pulmonary function in humans. Acta Physiologica Scandinavica, 1996;158:343-347.
• Choi JE et al. Intraoral pH and temperature during sleep with and without mouth breathing. Journal of Oral Rehabilitation, 2016. DOI
• Internal nasal valve review. Frontiers in Surgery, 2025. Frontiers

This guide is general information about breathing and is not medical advice. If you have ongoing breathing or sleep problems, talk to a healthcare professional.