Why I switched to nose breathing when running – And why you should too

If you want as much oxygen as possible when you run, should you nose breathe or mouth breathe? You might be surprised to find out which one is the most inefficient way to breathe when running. 

In today’s post, I’m going to guide you through my decision to switch to nose breathing when I run and why you should too. There’s a little bit of science and a little bit of a mental challenge behind the decision, and I’m curious to know which one sways you to make the change, too. 

A few years back, I got wind that I may have been breathing wrong. After reading the book The Oxygen Advantage by Patrick Mckeown, I became much more aware of the breathing habits of myself and others around me. And while it sounds odd that we all may be breathing wrong, once you start understanding the physiology around breathing, the concept of efficient versus inefficient breathing starts coming together.

The Mouth or the Nose?

Next time you’ve got a spare few seconds, do a quick breath check. Is your mouth open? Are you breathing through your mouth or nose?

Go on, check right now. 

If the answer is your mouth, why is that? We have an organ dedicated to taking in air from the outside world, your nose. So why would we be using our mouth for what the nose is made to do?

The quick answer is, if you don’t use it, you lose it. 

That’s to say when you stop using your nose to breathe, the erectile tissue in your nose begins to close up and may even form polyps blocking the airways. 

The reasons why your nasal passages close up in the first place are numerous. Allergies, congestion, poorly formed mouth and jaw, and enlarged tonsils can all be the catalyst for chronic mouth breathing, and once it starts to occur, reversing it becomes more challenging. 

The true tried and tested way to regain the use of your nose is to start using it again. All the time!

Why we Should Choose Nose Breathing over Mouth Breathing

So, what’s the big deal with mouth breathing? You can still get air in and out of your lungs efficiently, right?

That may be true, but the nose has unique properties, which means it’s the swiss army knife of airways. 

Nitric Oxide in the nasal passages and sinuses

Although Nitric Oxide (NO) is toxic in high amounts, the small amounts released by the nose helps blood vessels dilate, reducing blood pressure and increasing blood flow.

NO also allows the Alveoli (air sacs in the lungs) to open further, allowing for more oxygen and carbon dioxide transfer during the breathing cycle. 

Lastly, NO is also a potent antibacterial agent that kills viruses and gems and ensures they do not enter the airways. Since we all know about airborne viruses now, we should all be keen on using the nose more often.

Raising the concentration of CO2 in your blood

Errr, What? 

Don’t we want as much oxygen in the blood as possible? 

No. And the reason comes down to a phenomenon known as the Bhor effect. 

When CO2 increases in your blood, the blood pH lowers. This lower pH level helps offload oxygen into areas of your body that require it, i.e., muscles when you’re running. 

In short, there’s a reduction of oxygen from lighter breathing, but that’s offset with a raised efficiency of oxygen delivery.

Humidify the air

Have you ever completed a hard workout, and your lungs are burning?

A simple solution would have been to nose breath. 

When you breathe through your nose rather than the mouth, you humidify the air moving down into your lungs, which helps two-fold. One, it reduces the inflammation you feel when breathing heavily. Two, you minimize the possibility of dehydration. Yes! That means you may not need to drink as many fluids on your runs!

How do I Start Nose Breathing When I Run

Just do it!

Ok, it’s not going to be that easy. But here are the steps I took.

  1. Go for a walk and consciously nose breath throughout. Trust me; it’s harder than you think.
  2. I tried to catch myself every time I was mouth breathing during the day and actively switched to my nose.
  3. I taped my mouth shut every night with a small piece of medical tape.
  4. I slowed my run down and tried to nose breath throughout. 

That last one was the hardest. My pace slowed. But that wasn’t a problem! 

As a secondary effect, it pushed much of my training into zone 2 (slower heart rate), meaning it was easy but still improving my aerobic base (endurance) and biomechanics. 

Setting your expectations

It’s going to take time to transition to nose breathing during your runs. 

It won’t be easy right away/ You’ll probably have to blow a lot of snot rockets. But don’t worry, that’ll reduce the more you nose breath. Over time, you’ll notice that your nasal passages will begin to open up and become more comfortable –even while you run! 

Your mouth will drop open now and then. Sometimes without you even thinking about it. If you notice that you’ve switched back to mouth breathing, relax and reset. 

There are some instances where you cannot get away with nose breathing—for example, grinding up that big hill or sprinting. Your oxygen requirement becomes so large that your CO2 levels naturally rise in your bloodstream, even when mouth breathing! So if it’s not possible to slow down – I’m thinking the race environment – then mouth breathing is acceptable. And this works for anything up to 5km.

What you want to focus on is your default. Your nose should do the majority of the work, and your mouth should rarely drop open for a breath. 

The unexpected side effects of nasal breathing when running

I’ve always been a goal-driven runner, but only in the short term. I’d want to post the best time in every training session or complete an athletic feat every weekend. As you can imagine, doing so is not sustainable.

When I started focusing on nose breathing, it redirected my drive onto a different goal. Nose breathing through the duration of my runs forced me to slow down and train in a more sustainable zone. If you don’t know why that’s a good thing, send me a quick message, and I’ll give you the low down.

If you’re a type-A kind of person, or you’re someone that goes and crushes every workout, then nose breathing is for you. It’ll bring balance back to your training and still improve your athletic efficiency. 

All you need is practice and patience. 

After a month or so, you’ll be comfortably nose breathing during your runs, and then you’ll want to push it further and complete interval training while nose breathing. It’s a whole new journey, but a stimulating one!


Nick helps aspiring runners learn how to take a healthful approach to their training and races so they don’t crash and burn before they achieve their goals.

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