Mouth Breathing vs Nose Breathing: Is There a Right Way to Breathe?

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Spoiler alert: yes there is

Are you a mouth breather?

Don’t worry; this isn’t meant to be a middle-school insult.

As it turns out, mouth breathing is scientifically linked to various health issues, like poor cognitive performance, dental problems, snoring, and messed up sleep. While breathing through your mouth may seem like a way to get more oxygen, research says the opposite.

mouth breathing vs nose breathing

When you breathe through your nose, the air gets filtered and humidified, which means your cells get more oxygen.

Full disclosure: nasal breathing has become an obsession after reading James Nestor’s book “Breath: The New Science of a Lost Art” (highly recommend). I also learned a lot about breathing mechanics in this episode of The Huberman Lab Podcast.

Today, I’ll explore mouth breathing vs. nose breathing and give you some tips to breathe more efficiently for peak performance.

The Science of Breathing

Understanding the role of carbon dioxide in breathing

Breathing is essential for our survival. Not many of us could survive without oxygen for a few minutes. However, it may surprise you that it’s the waste gas carbon dioxide (CO2), and not oxygen, that provides the impetus to breathe.

Specialized cells in the brain stem called chemoreceptors keep an eye on the levels of CO2 in our bloodstream. When CO2 levels rise too high, our brain sends signals to increase the rate and depth of our breathing to get rid of excess CO2. On the other hand, when CO2 levels drop, we don’t need to breathe as much because that stimulus isn’t there.

So, what does all this mean?

Well, it plays a key role in how oxygen gets delivered to our cells and organs. The build-up of carbon dioxide in the blood is like a switch that tells our body to release oxygen to where it’s needed. This is known as The Bohr Effect.

Here’s how it works:

Red blood cells (RBCs) transport oxygen throughout your body inside a protein called hemoglobin.

When there is a higher blood concentration of CO2, hemoglobin loosens its grip on oxygen, allowing it to release more oxygen to your cells and tissues. Conversely, when the CO2 concentration in the blood is low, hemoglobin tightens its bond with oxygenpreventing it from being released to tissues efficiently. It may also lead to the constriction of airways and blood vessels to prevent the further loss of CO2.

In sum, more oxygen isn’t always better. The levels of CO2 in the blood play a vital role in the chemistry of breathing, which is often overlooked.

The Effects of Mouth Breathing vs. Nose Breathing

Most of us take breathing for granted. Why wouldn’t we? It’s an automatic process that takes care of itself. That said, whether you’re habitually breathing through your mouth or nose can significantly impact your overall well-being.

Let’s explore the importance of nasal breathing and its benefits compared to mouth breathing.

The Benefits of Nose Breathing

Your nose is designed for breathing. It is equipped with tiny cilia, which act as filters, warming and humidifying the air that enters your lungs to match your body temperature. The cilia capture billions of airborne particles, such as dust, pollen, and bacteria, ensuring your airways stay clear and healthy. In short, the nose acts as a state-of-the-art air-conditioner and filter for your respiratory system.

Another cool thing your nose does is gather nitric oxide (NO) from the sinuses and draw it into your lungs. NO acts as a vasodilator, promoting better circulation, blood pressure, and oxygen diffusion to your cells.

Nasal breathing creates resistance, which activates your “breathing muscle”, the diaphragm (1). Diaphragmatic breathing – or belly breathing – draws air deep into your lungs where there is a greater density of blood vessels to absorb more oxygen. 

Plus, nasal breathing reduces your overall breathing volume, which helps you balance CO2 better and improves oxygen delivery to vital tissues like your muscles and brain. Despite inhaling less air during nasal breathing, your cells absorb more oxygen than breathing through the mouth.

It’s also no surprise it’s associated with a more “switched-on” brain and better cognitive function, as per this study. The benefits are almost endless.

Overall, your nose is your preferred breathing tool. It’s more efficient, allowing you to use more energy on cellular repair and other functions.

The Drawbacks of Mouth Breathing

While your mouth is great for talking, eating, and kissing, it isn’t all that great for breathing.

Sure, there are times when you must breathe through your mouth, like when you’re congested or training hard. That said, it doesn’t offer any of the added health benefits of nasal breathing, like filtering or humidifying the air. It can also dry out the mouth, a recipe for gum disease, gingivitis, tooth decay, and poor oral health. Plus, breathing through the mouth dehydrates the body faster, especially during physical exertion (2).

James Nestor found out the hard way about the effects of mouth breathing while researching “Breath: The New Science of a Lost Art.” Stanford University researchers completely blocked his nose with silicone and surgical tape for 10 days. He was forced to breathe through his mouth day and night while researchers measured several health markers.

James expected to feel uncomfortable, but he had no idea what a mess it would be. His blood pressure and heart rate went up, heart rate variability (HRV) declined, and oxygen levels dropped. He even developed obstructive sleep apnea, likely due to his tongue blocking the airways during sleep. Needless to say, his sleep quality fell through the floor, and he felt fatigued and foggy-headed as the experiment went on.

I realize this wasn’t a controlled trial, but given what we know about nasal breathing, the results are hard to deny.

Mouth Breathing Is Over-Breathing

When you breathe through your mouth, it’s usually shallow rapid breathing into the upper chest (also called hyperventilation). This can make you feel more stressed and tired. It also weakens the diaphragm, creating a vicious cycle of mouth breathing that becomes a habit over time

Subsequently, this messes with your CO2 levels, which means your cells receive less oxygen overall.

The Effects of Mouth Breathing on Facial Development

This is a controversial topic, but mouth breathing during childhood can potentially alter the structure of the face, jaw, and teeth (3).

Nasal breathing provides a natural resistance to support normal facial development. However, when you breathe through your mouth, your tongue doesn’t sit on the roof of the mouth where it’s supposed to, which can lead to poor muscle and bone development. This contributes to the narrowing of the dental arch, a receding chin, a weak jawline, crowded teeth, a forward head posture, and other not-great stuff. It gives mouth-breathing children (and adults) a certain “look.”

mouth breathing vs nose breathing

a well-known mouth breather

Unfortunately, your facial structure is hard to shift as an adult. Encouraging healthy breathing patterns from a young age is essential. It’s another reason breastfeeding in infancy supports proper development – the mouth position sets a child up for a strong facial structure and a lifetime of nasal breathing.

The Risks of Mouth Breathing at Night

If you wake up with a dry mouth, sore throat, or bad breath, you’re probably mouth breathing during the night, which can have severe health consequences. 

Studies suggest a link between mouth breathing during sleep and a higher risk of sleep apnea. The tongue lies at the back of the mouth, restricting airflow and preventing you from getting quality restorative sleep. 

Furthermore, research shows people experiencing nasal congestion at least five nights per month are more likely to suffer from snoring, restless sleep, and daytime fatigue.

Note: Habitual mouth breathing during sleep may indicate an underlying airway issue. It’s essential to consult a healthcare professional to address obstructive sleep apnea, deviated septum, nasal polyps, nasal inflammation, or enlarged adenoids. Proper treatment may prevent mouth breathing during sleep and give you the quality rest you deserve.

Mouth Breathing vs. Nose Breathing in Athletes

Mouth breathing is often the default during exercise, especially when exerting maximum effort, because of the higher oxygen demand. Your muscles produce more carbon dioxide during physical activity, triggering a feeling of air hunger. Breathing through the mouth expels CO2 quickly and helps you take in larger volumes of air, functioning almost like a “cheat code” for your brain.

However, a higher respiration rate tires you out quickly, leading to breathlessness and muscle fatigue.

The impact of mouth breathing on oxygen delivery and performance

Mouth breathing gets rid of more carbon dioxide, altering your blood chemistry. This triggers hemoglobin to hold onto more oxygen, depriving your muscles of the crucial energy they need (remember the Bohr Effect). Paradoxically, this makes you breathe even more, contributing to exercise-induced asthma, a common problem among runners.

Nose breathing during exercise may be more efficient. It may sound crazy, but a lower breathing volume during physical activity can improve oxygen delivery to your muscles, giving you more stamina.

Can nose breathing really improve sports performance?

What sets high-ranking athletes apart from the rest may come down to lower CO2 sensitivity and a more efficient respiratory rate. In fact, top athletes like Novak Djokovic credit breathwork for their focus on the court. If you watch him play, he rarely has his mouth open, instead predominantly using nose breathing to stay focused and save energy.

This 2018 study looked at mouth breathing vs. nose breathing in runners. Researchers found that peak oxygen uptake (VO2 max) remained the same regardless of the breathing method. However, nose breathing lowered the respiration rate (or the total number of breaths per minute during exercise), meaning the athletes exerted less effort overall.

Another controlled study on basketball players found following a nasal breathing protocol during intermittent running exercises improved their fitness, recovery, and lung function.

How to Stop Mouth Breathing and Improve Nasal Breathing

So, can mouth breathers become nose breathers?

In many cases, you can learn to breathe primarily through the nose by adopting new habits and techniques.

Work on your jaw and tongue positioning. Your mouth should be closed (duh), your tongue resting on the roof of your mouth, just behind your front teeth. Keep your jaw relaxed and your teeth slightly parted.

If you have allergies or congestion, regularly rinsing your sinuses with a saline solution may open your nasal cavity and make breathing easier.

However, if you suspect a nasal obstruction, you need to address the underlying medical issue before you can breathe through your nose safely with ease.

Breathing Techniques

There are lots of breathing protocols that direct your breath in and out of your nose. However, the first step is to become aware of your breathing patterns. Take frequent pauses throughout the day to notice your breathing and redirect your breath back to your nasal airways when necessary.

In addition, I like practicing coherent breathing for 10 minutes each day. Find a comfortable position and breathe slowly in and out through your nose for a count of 4, engaging your diaphragm. This technique stimulates your parasympathetic nervous system, helping to improve CO2 tolerance over time and reduce air hunger.

Mouth Taping

Many people swear by mouth tape, or sleep tape, as a reminder to breathe through the nose. Using medical-grade tape to gently hold the lips closed can promote nasal breathing without causing skin irritation.

There’s no doubt this is a useful tool, especially during sleep. However, I recommend using it during the day at first to get used to the feeling. Consider using a small strip of micropore tape while working, doing chores, watching TV, or taking a slow walk to retrain your breathing.

That said, only use mouth tape if you don’t have any congestion or sinus abnormalities.

Nasal Breathing Tips for Athletes: Take It Slow

Now that you know about the benefits of nose breathing on performance, you might be tempted to jump straight in. Resist that urge.

Transitioning from mouth to nasal breathing during exercise can feel stressful initially, especially during intense workouts. In fact, your oxygen uptake and time to exhaustion may be negatively affected if you jump right into nasal breathing. So, I’m not suggesting you stress your cardiovascular system by diving in headfirst.

The key is to start gradually and let your body adapt by practicing nasal breathing during warm-ups, cool-downs, and recovery.

As your CO2 tolerance improves, you can build nasal breathing into low to moderate-intensity exercises like walking, slow jogging, or gentle cycling. Mouth tape may be helpful initially as a reminder to keep your mouth closed.

However, if your nasal breathing falls apart during lower-intensity exercise, there’s no point in pushing the envelope. Dial it back until your breathing recovers and try again.

Keeping this up for 6–8 weeks can improve your CO2 tolerance, which is where the magic happens.

Once you’ve demonstrated you can maintain nasal breathing during low-intensity activity, you can expand the speed, intensity, and length of exercise.

The Gear System: Breathing for Peak Performance

While nasal breathing should be a priority, you can use mouth breathing strategically to control your output.

In the book “Breathe, Focus, Excel” by Harvey Martin, he refers to the Gear System. Depending on the exercise intensity, you can use different nasal and mouth breathing variations to optimize your performance.

  • Gear 1:  Inhale and exhale through the nose normally and evenly.
  • Gear 2:  Power inhalation through the nose and normal nasal exhalation.
  • Gear 3:  Power nasal inhalation and power nasal exhalation.
  • Gear 4:  Power nasal inhalation and mouth exhalation.
  • Gear 5:  Mouth inhalation and mouth exhalation.

By shifting up or down through the gears, you can consciously adjust your blood chemistry and adapt to the demands of your workout. Gears 1 and 2 work well for low and moderate-intensity exercise, while gears 3 to 5 come into play during activities that require maximum effort.

Pay attention to your exertion level and adjust your breathing accordingly. Shift up through the gears as you increase your effort. Likewise, you can drop down through the gears as the workout intensity levels out to continue nasal breathing for as long as possible.

Remember, the idea is not to push yourself too hard or experience extreme discomfort. With practice, your CO2 tolerance will improve, and you’ll be able to stay in the lower gears for longer.

Overall, the effectiveness of nose breathing during exercise depends on the specific sport or activity. If you’re struggling to sustain nasal breathing, consult your healthcare or fitness professional for advice. You may require tools like nasal dilators or decongestants to help you breathe through your nose.


Let’s address your Qs about mouth breathing vs nose breathing.

What Causes Mouth Breathing?

Mouth breathing can be caused by various factors, some of which may require medical treatment. This may include allergic rhinitis, sinus infections, enlarged adenoids and tonsils, asthma, nasal polyps, weight gain, obstructive sleep apnea, or a deviated septum.

However, mouth breathing may also be a habit from childhood. That said, it’s never too late to relearn nose breathing.

What Are the Side Effects of Mouth Breathing?

While necessary in certain situations, chronic mouth breathing isn’t good for overall health.

Common side effects include poor dental health, bad breath, increased risk of respiratory infections, changes in facial structure, crowded teeth, snoring, unrefreshing sleep, low energy levels, and reduced physical performance and recovery.

Is There a Breathing Exercise to Reduce Nasal Congestion?

To relieve nasal congestion, Patrick McKeown, author of “The Oxygen Advantage” (another great read), suggests the following exercise:

  • Take a normal breath in and out.
  • Pinch your nose and hold your breath.
  • Gently nod your head as you hold your breath.
  • Keep holding until you feel a moderate to strong air hunger.
  • Let go of your nose and breathe in and out normally through your nose.
  • Repeat 5-6 times.

This exercise increases nitric oxide in the sinuses, dilating the airways and alleviating congestion. It’s great for those who experience congestion due to seasonal allergens.

Is Mouth Taping at Night Safe?

Mouth tape is growing in popularity, with social media “influencers” touting the benefits to millions of followers.

When done correctly, mouth taping is safe for otherwise healthy people. However, it’s not safe for everyone. It may be downright dangerous if you have an airway obstruction or are prone to panic attacks.

Consult your healthcare provider before trying mouth tape and use it for short periods during the day before mouth taping during sleep.

Final Thoughts on Mouth Breathing vs. Nose Breathing

In sum, breathing through your nose supports oxygen uptake as the nasal passages warm, humidify, and filter the air before it reaches the lungs. Over time, nasal breathing may reduce stress levels, improve sleep quality, improve lung capacity, and support performance. Many high-level athletes have already embraced nasal breathing to save energy, maintain a sense of calm, reduce dehydration, and boost focus.

If you’re a recovering mouth breather, be mindful of your breathing habits and gradually work on incorporating more nasal breathing exercises into your day to retrain your respiratory system. However, don’t stress about controlling your breathing 24/7. Breathing happens whether you’re aware of it or not, so trying to nose-breathe all the time can be counterproductive.

Finally, if you have any underlying medical concerns, consult a healthcare professional before taking advice from this article.

About the Author

Katherine is a South African-born nutritionist, freelance wellness writer, and rooibos tea enthusiast (iykyk). When she's not researching new "biohacking" trends and writing for her clients, you'll find Katherine swimming at a local Cape Town beach or practicing breathwork at any opportunity.

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