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Shut Your Mouth: Why Mouthbreathing is So Bad for You

Hey Readers! I am so glad to be back to blogging! I took a two-month hiatus to enjoy my summer vacation and to take time to plan new and improved content for y'all. I hope your summer break was filled with lots of fun!

In today's post, I will go over why mouthbreathing is so damaging to the human body. You might be thinking - "I breathe everyday, so why does this information pertain to ME?" Okay, valid question. BUT...if you are not breathing with optimal mechanics, quite literally everything in your body suffers. And, the truth is, most of us are actually not breathing correctly. Indeed, recent research, has suggested that about 90% of all humans breathe incorrectly, and these incorrect breathing patterns can either cause, or aggravate, a long list of chronic diseases.

Before we delve deeper into the content of this post, let's go over some background information that may be helpful for understanding this blog post. Breathing, also referred to as respiration, involves the coordinated action of the lungs, rib cage, diaphragm, trunk muscles, and the nervous system, all in an effort to take in oxygen and release carbon dioxide with each breath. If you want to learn more about breathing physiology in general, please refer to one of my earlier posts on this topic (click here). The average person breathes about 12-20 times per minute. That translates to approximately 17,280 - 28,800 breaths per day, and if you're breathing incorrectly (such as mouthbreathing), that is a lot of opportunity for the negative consequences of faulty breathing to take effect in your body.

Mouthbreathing is unfortunately becoming a very common breathing pattern for many humans. But, mouthbreathing is HORRIBLE for the human body. Humans have evolved to breathe through the nose. Now, obviously, when you have a cold and your nasal cavity is congested, of course you have to breathe through your mouth. But, breathing through the mouth "on the regular" is not a good thing, and it leads to so many issues in the body.

Why is Mouthbreathing Bad for the Body?

It is well-known that breathing through the nose is important for warming, moistening, and filtering the air we breathe. Most basic biology and anatomy courses will teach this. And while this is totally true and SUUUUPER important, there are so many other reasons to regularly breathe through the nose and avoid mouthbreathing.

Mouthbreathing changes the shape of the oral cavity and airways. Just like any other body part, the nasal and oral cavities respond to whatever input they receive. When you inhale/exhale through the nose, it trains those soft tissues to generate tension and flex to stay open. However, when you regularly breathe in/out through the mouth, the soft tissues in the nasal cavity are not stimulated to generate tension. Hence, they become loose and flaccid, and eventually those tissues will slacken inwards, reducing the diameter of the airway. This creates less space, making nasal breathing more challenging, resulting in even more mouthbreathing. Mouthbreathing also causes the jaw to shift its resting position, and this can lead to malalignments and dental issues. In fact, 90% of all children have developed some degree of deformity in mouths and noses, and some of this is related to mouthbreathing. The good news is that your facial structures can morph back into a more natural shape once you resume nasal breathing as your primary breath pattern.

Mouthbreathing changes the structure of the brain. When you breathe in/out through the mouth regularly, it can negatively change the structure of the brain. Specifically, it appears that mouthbreathing results in fewer brain cells developing and maturing. Also, some studies in rats have shown that when rats were forced to breathe through their mouths, they also developed fewer brain cells compared to rats allowed to breathe through their nose.

Mouthbreathing causes cognitive-emotional issues and deficits. Regular mouthbreathing can wreak havoc on cognitive and emotional functioning. Depression has been linked to mouthbreathing. When mouthbreathers restored their nasal breathing pattern, their depression symptoms lessened significantly. In addition to depression, mouthbreathing reduces the amount of oxygen delivered to the prefrontal cortex (PFC) in the brain. The PFC is responsible for cognitive functions such as working memory, attention, and executive functioning (e.g. goal setting, time management, inhibition, etc.). Finally, mouthbreathing decreases heart rate variability (HRV), which is essentially a measure of autonomic nervous system (ANS) functioning. In general, a low HRV is considered unhealthy, and it is associated with depression, anxiety, and reduced flexibility in the ANS. A high HRV is considered healthy, and it is associated with stronger emotional health and more flexibility in the ANS. If you want to learn more about the ANS and HRV, please refer to my earlier blog posts on these topics (ANS click here, HRV click here).

Mouthbreathing causes less oxygen to be delivered into cells. When you breathe in/out through your nose, your sinuses actually release a large amount of nitric oxide (NO), which increases circulation, and subsequently oxygen delivery, to the cells of your body. Increased circulation from the NO also helps with removing waste products from your body's cells. Additionally, immune function, body weight, mood, and sexual function are all heavily influenced by the amount of NO in the body. Indeed, nasal breathing can increase the level of NO in the body by 6 times!

Mouthbreathing is linked to many other chronic conditions. Breathing through the mouth is also linked to many other chronic conditions, including: ADHD, diabetes, high blood pressure, and cancer. Also, some research suggests that chronic insomnia is often caused by breathing problems.


As this post summarizes, breathing really needs to occur through the nose rather than through the mouth. Unfortunately, many people habitually breathe through their mouth, and this mouthbreathing is often the cause of many chronic health conditions. Nasal breathing is so much better for the body compared to mouthbreathing. When you regularly breathe through the mouth, the shape of your face and the structure of your brain changes, you can experience cognitive and emotional issues, less oxygen gets delivered into the cells, and it can cause many other chronic conditions. So, shut your mouth when you are breathing (if possible), and start to regularly inhale/exhale through your nose. Thank you so much for reading this post! I'll be back in another month with another health/wellness post. Until then, go be good people and spread lots of love!

As always, the information presented in this blog post is derived from my own study of neuroscience, human movement, anatomy, and yoga. If you have specific questions about your breathing, please consult with your physician, physical therapist, personal trainer, or private yoga teacher. If you are interested in private yoga and/or personal training sessions with me, Jackie, email me at for more information about my services. Also, please subscribe to my website so you can receive my weekly newsletters (scroll to the bottom of the page where you can submit your email address). This will help keep you "in-the-know" about my latest blog releases and other helpful yoga and wellness information. Thanks for reading!

~Namaste, Jackie Allen, M.S., M.Ed., CCC-SLP, RYT-200, RCYT, NASM-CPT, NASM-CES


Nestor, J. (2020). Breath: The New Science of a Lost Art.

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