Tongue Health & Breathing: Dr Felix Liao

I had the pleasure of speaking with Dr Felix Liao, the Airway Mouth Doctor. Why is the tongue the “six-foot tiger”, and the mouth the “three-foot cage”? Tune in to find out more.

Do You Keep Your Six-Foot Tiger in a Three-Foot Cage?

This week, I had the pleasure of speaking with Dr Felix Liao. Felix is an airway mouth doctor, and Felix is passionate and prolific in his writings. He’s written many books. Your Child’s Best Face, where he explores why a better face means better health. He talks about some red flags that we should look out for. 

Red Flags

The whole health logic. If you’re getting the sense that there’s a lot more going on in your face and your mouth than you may have thought. I make no apology for that. I always say that I include dental stress as one of the five stressors emotional, environmental, postural, nutritional and dental stress. Everybody nods when I mention the first four. When I get to the dental stress, they look bemused. The reason I include dental stress is really for two reasons. 

I’ve been involved in this field for over 40 years now, so I feel reasonably well-qualified to share my knowledge with you. But the second reason I included is I included for anybody with a mouth who is interested in their health but has never fully connected the two. Many regular listeners to this podcast will know there are many connections. One that we focus on repeatedly from various connections by various angles is the mouth. 

Some red flags and bringing on your best face. So that’s something that Felix talked about in his book, Your Child’s Best Face. He also talked about RelaunchYour Vitality: The Missing Key to Getting Free From Chronic Pain and Fatigue. There’s something like 20 to 40% of the population suffering from chronic musculoskeletal pain. 

Chronic Pain and Fatigue

That could be chronic backaches, often it is, but it also includes what people often describe as tension headaches and neck aches. Most people will seek out the help of a physio or a chiropractor, or an osteopath to deal with those issues. I think that’s entirely appropriate. I think that’s a good place to start. 

If you are suffering from chronic musculoskeletal pain and need to constantly every month or go back for treatment, you need to be asking yourself a very fundamental question: Why is this recurring? If you walk out of your chiro osteo physio’s office with relief of pain and a few weeks later that pain recurs, you have to ask yourself why? 

A part that is often overlooked is the role of the jaw, particularly in the way you breathe, the way you sleep, and the way that affects your posture, predisposing you perhaps to a head forward posture, which would put a strain on the muscles at the back of the neck or the side of the neck, which would cause frontal headaches or temporal headaches or headaches at the back of the head. And the role of clenching and grinding and all of that, which we now know, is often linked to disordered breathing, particularly when you’re asleep. This is why Felix has included chronic pain in his Relaunch Your Vitality. 

He’s also written a book called Early Sirens: The Critical Health Warnings and Holistic Mouth Solutions For Snoring, Teeth Grinding, Jaw Clicking, Chronic Pains and Fatigue. He puts out various red flags like crowded lower front teeth. You’re grinding your teeth. You know, you’ve got dry mouth, or you’ve got narrow jaws and crowded teeth. But the one that I really like is Felix’s book, Six-Foot Tiger, Three-Foot Cage.

Felix focuses on a person’s tongue

He’s referring here, of course, to a person’s tongue. The thing that is important to note is that your tongue needs sufficient room to fit into your mouth. You can look at your mouth and see whether you have indentations of your teeth on your tongue. That gives you a clue as to whether you might be clenching or grinding. 

It might give you a clue that you have insufficient room. You might be just providing your six-foot tiger, the tongue, with only a three-foot cage. When you think about it, how do soft tissues like a tongue have permanent indentations on them from the teeth?

I always draw the analogy that if I was to lean my arm against the edge of a table and leave it there for half an hour, or maybe even only after 10 minutes, I have the indentation or the line of the edge of that table on my arm. But for it to be there permanently, I’d have to keep my arm pressed permanently against the table. 

Well, to have indentations of the type that you have of your teeth on your tongue or on your cheeks, you can look at your cheeks as well and see if there’s a line there where your upper and lower teeth meet together. But it’s the tongue that Felix is focussing on, and it’s the tongue we should be focussing on. Because if you don’t have enough room for your tongue in your mouth, you’ve got three alternatives – You could walk around with your tongue sticking out. 


Not a great look and not many people do that. The other way is to breathe through your mouth by just slightly opening your mouth and giving a little bit more room for your tongue to sit there. But the problem with that is that you’re breathing through your mouth. Noses are for breathing, mouths are for feeding and talking and smiling. But they are not primarily there for breathing. 

Any regular listening to this podcast will know that nasal breathing has so many positives to it. It warms, humidifies, and filters the air before we take it into our lungs. There are fine hairs in the nose which filter out particles. There is the mucous lining, the sinuses in the turbulence, which also grab onto pollutants or viruses. 

There are the sinuses and the turbulence, which warm and humidify the air before you are taken into your lungs. There are also the adenoids and then, finally, the tonsils. There are four or five there that are lines of defence if you breathe through your nose.

If you breathe through your mouth, you bypass the first four and rely on your tonsils. People who have recurring throat infections, particularly children who have recurring upper respiratory infections or enlarged tonsils, are often a reflection of predominantly a mouth breathers. 

Another feature of breathing through your nose is nitric oxide. I should just take a step back from you. Nitric oxide. Nitric oxide, NOT nitrous oxide. Nitrous oxide is a laughing gas that you may have had in dental surgery. Or if you’re a woman, when you’ve given birth to a baby, you’ve given sometimes nitrous oxide as a sort of or sedative, if you like. 

This is nitric oxide. And nitric oxide is one of the body’s main regulators. It’s a really important compound. It’s a natural vasodilator. So it releases the pressure in the blood vessels. Good for blood pressure. It’s a bronchodilator, so it opens up the airways. It’s also anti-microbial and anti-viral. Yes, nitric oxide.

After the Sars-Cov-1 virus in 2003, there was some interesting research which showed that nitric oxide disrupted the reproductive cycle of the virus. If you did that for Sars-1, they did it for Sars-2. Although in the current pandemic, you know, we haven’t heard anything about the importance of that. 

We haven’t really heard anything about anything other than the importance of vaccinations and social isolations and masks. But that’s a whole other story. Nitric oxide is also an anti-microbial antiviral, and 60 to 90% of the body’s nitric oxide is produced in the paranasal sinuses only when you breathe through your nose. The more I learn about nasal breathing, the more important I find it to be. This six-foot tiger, your tongue, in a three-foot cage, your mouth. 

You have three alternatives. (1) One, to walk around with your tongue sticking out. Not good. (2) The other is to have your mouth slightly open and be predominantly your mouth breather, giving more room for your tongue but creating all sorts of other problems. (3) And the third way is for you to close your mouth, but your tongue not having enough room has the potential to block your airway and restrict your upper airway, which creates all sorts of other problems for you.

So having enough room to house all of your teeth is much more than whether you have enough teeth to chew the food that hunters and gatherers chewed because, just like hunters and gatherers, it’s really important. In fact, arguably even more important now than ever before is to breathe well and sleep well, to build resilience into our system, our bodies. 

This is why this week’s episode with Felix Liao, the airway mouth doctor, was such a joy to talk to Felix. He’s another very passionate practitioner. He’s very prolific in his writings, and it was just so interesting to meet and chat with him. But it reminded me of all of those things, and I want to remind you too. I hope this finds you well. Until next time.



This podcast provides general information and discussion about medicine, health, and related subjects. The content is not intended and should not be construed as medical advice or as a substitute for care by a qualified medical practitioner. If you or any other person has a medical concern, he or she should consult with an appropriately qualified medical practitioner. Guests who speak in this podcast express their own opinions, experiences, and conclusions.