Nose breathing science vs. snake oil

Are you breathing wrong? Learn the good, bad, and ugly of this new wellness obsession.

Aug 12, 2024

Post summary

“Nasal breathing” and other breathing techniques have become a massively hyped topic in health and fitness.
Proponents say nasal breathing can boost heart health, fitness performance, sleep, and immunity while also reducing our reduce stress—and much more.
- These people even say you’re breathing “wrong” if you breathe through your mouth.
We spoke to scientists and read the research to separate what’s helpful from what’s hype in the breathing world.
The result: A no-BS guide to breathing. It’ll help you focus your time and energy on what actually works so you can improve your health and fitness in less time.

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The post

Humans have long known that the way we breathe impacts our health. Consider the ancient Sanskrit Proverb:

“For breath is life, and if you breathe well you will live long on earth.”

But today, many in the health and wellness world say you’re only breathing “well” if you’re breathing through your nose. Breathing through your nose—called “nasal breathing”—is having a moment.

We have bestselling books on breathing, expensive breathing workshops, and a host of contraptions that supposedly help us breathe “right.”

This new focus on the breath is largely a good thing.

As you’ll soon learn, breathing through your nose instead of your mouth may help you live and perform better in some scenarios.

And that matters because roughly a third of Americans are chronic “mouth breathers,” according to one review.

But some in the wellness world now claim that breathing through your nose is the “right” way to breathe while breathing through your mouth is “wrong.”

If there’s one thing I’ve learned while reporting on health and fitness for nearly two decades, it’s that absolute rules are absolutely some degree of wrong.

I read way too many studies and spoke with researchers in the field of breathing. I learned that there is a time and place for all different types of breathing—and knowing which to deploy when it matters can be a game changer.

Today’s post dives into nasal breathing:

Why humans are unique in how we breathe through our nose.
How breathing through your nose versus your mouth impacts your health and performance.
Where we tipped into insanity around nasal breathing.
How to use nasal breathing in three exercise scenarios: during strength, interval, or cardio workouts.
On Wednesday, we have a super helpful post explaining how I use this information in my own life (my favorite breathing trick).

Let’s roll …

The 2.5-million-year history of nasal breathing

Section summary: Humans evolved to have noses that protrude from our face. Our uniques noses altered how we breathe and improved our ability to cover great distances and explore the world.

Human noses are special. They’re relatively big, and they protrude from our faces.

For example, if you look at a chimpanzee, our closest ancestor, their nose doesn’t jut out much. It’s rather flat on their face. Yet our noses protrude.

We didn’t always have noses like this. And when we got them, we became far better athletes.

Some history: Our ancestor from ~3 million years ago, Australopithecus, was the final step into the appearance of humans, the genus homo. But Australopithecus didn’t have noses that jutted off of their faces.

Yet, as we evolved into humans, our noses grew farther from our faces. For example, our direct ancestors from two million years ago, Homo Habilis and Homo Erectus, had protruding noses.

The evolution of the human face. Notice that noses protrude more over time.

These protruding noses were and still are massively helpful: They help us walk, run, and carry items long distances across the earth.

To understand why, first consider your dog. When she breathes in through her nose, the air takes a horizontal, straight path into her lungs. That hot, unfiltered air dries out the lungs and causes more water loss and body heat.

But the air humans breathe in doesn’t take a straight shot into our lungs. When we breathe into our nose, the following happens:

Air goes vertically up into our nostrils.
There it takes a 90-degree turn and runs through valves that lead into your inner nose. Here it swirls around in a sort of vortex.
As the air swirls, it makes contact with the mucus membranes that line your inner nose. This mucus holds water.
Hotter, dryer air swirling around this area pulls water from your mucus, humidifying the air.
This humid air keeps your lungs from drying out.
Then, when we breath out, our nose recaptures the moisture due to the construction of our nasal cavity.

In short: Think of your nose as a swamp cooler that ensures your lungs don’t dry out and your body retains fluid on hot days. Harvard scientists wrote1:

“The evolution of large external noses in early Homo is strong evidence for selection to walk long distances in hot, dry conditions without dehydrating.”

On the flip side, our nose can also work as a furnace, warming air on cold days so frigid air doesn’t go directly into our lungs. That helps humans do well in cold climates.

As people migrated out of the hot African Savannas and into colder climates, their noses shrunk over time to make them better at warming air.2

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How breathing through your nose impacts health

Section summary: Breathing through your nose is linked to various positive health benefits. But some benefits may be placebo and may only apply to sick people.

Along with upright walking, sweating, curiosity, and more, breathing through our noses made humans impressive endurance athletes who eventually took over the world.

Still today, breathing through your nose may benefit your health.

Compared to mouth breathing …

It may give us more oxygen per breath.
- “The level of oxygen conception in nasal breathing is higher than in mouth breathing,” said Mehdi Kushkestani, Ph.D., a breathing researcher. “When you have oxygen exchange in your lungs, you have better oxygen delivery to the tissues. This can save energy.”
- For example, one study suggests that oxygen uptake is a relative 10 to 20 percent higher per breath through the nose.
- Big caveat: This improved oxygenation may only matter in sick people. One review noted, “Data suggest that nasal breathing may improve arterial oxygenation in critically ill patients at rest, but there is little evidence that such benefits extend to healthy subjects.”
- We’ll cover the fitness implications of this below.
It may lower blood pressure and improve blood flow.
- A small study found that nasal breathing lowered systolic blood pressure (the bigger number on your blood pressure reading. It’s the force of your blood being pumped and is a better predictor of heart disease risk).
- Other research suggests nasal breathing improves blood flow in some regions of the lungs by 24 percent. This may have to do with nitric oxide production, which occurs through nasal breathing.
- Caveat one: The blood pressure benefits could just be because nasal breathing often slows down breathing and leads to deeper breaths. One review found deep breathing exercises lower blood pressure in people with high blood pressure.
- Caveat two: It’s not clear whether that improved lung blood flow would offer any significant benefits in healthy people.
It may improve our sleep quality.
- Not breathing through your nose at night is associated with sleep issues like sleep apnea.
- For example, one study switched men from mouth to nose breathing at night. The authors concluded, “when nasal breathing of snoring men was improved at night, their quality of life was significantly improved.” They slept better and were less tired the next day.
- This is why some people are taping their mouths at night.
- Caveat: If you already sleep OK, taping your mouth may hurt your sleep.
It may help us get sick less often.
- This is because our nose often filters out germs and particles. A summary of the topic suggest nasal breathing, “contributes to a lower probability of getting colds, flu, allergic reaction, hay fever, or irritable coughing” because the nose filters and humidifies the air going into our lungs.
- Caveat: Some of these findings are theoretical. Another review found that health benefits occur only in some sick people.
It may decrease stress levels.
- Fun observation: Dogs breathe through their mouth when they’re physically tired or stressed out—not that much different than humans!
- Research shows various nasal breathing techniques can reduce stress. More here. And yoga and meditation have long relied on controlled breathing to get into more relaxed states. This is called Ānāpānasati, Sanskrit for "mindfulness of breathing."
- Caveat one: Whether this benefit is via breathing through the nose per-se or a sort of meditative placebo effect is unclear. (I.e., Once you breathe through your nose with the intention of decreasing stress, you’ve cued yourself to relax.) For example, one review found, “results showed that breath work may be effective for improving stress and mental health. However, we urge caution and advocate for nuanced research approaches with low risk-of-bias study designs to avoid a miscalibration between hype and evidence.”
- Caveat two: If a “dumb” behavior drives your stress, it’s better to fix the behavior. For example, if you’re stressed over finances, you probably need to create a budget before you worry about nasal breathing.
It may increase memory and learning.
- This is very theoretical, but a wild study on epileptics who had electrodes implanted deep into their brains suggests that breathing through your nose leads to the generation of activity in our learning and memory centers that doesn’t happen when we breathe through our mouth (because only our sense of smell goes through these centers). It’s a far-out idea, but it’s plausible. More here.

Note that all of these points are “mays.”

Nasal breathing seems to benefit some people in some scenarios, but we need to learn more—and it’s certainly not a cure-all.

Yet the 2020 pandemic gave breathing techniques a “moment.”

The researcher Nick Tiller wrote, “The COVID-19 pandemic provided the perfect opportunity for snake oil salesmen to capitalize on widespread fear and confusion to sell breathing techniques.”

Especially in the fitness world …

The tip into nasal breathing insanity

Section summary: There’s a time and place to breathe through your nose. But focusing too much on breathing has led some to miss the larger picture of health and performance.

UFC 259 was the moment I realized we might be over-indexing on breathing techniques.

The headlining fight put Israel Adesanya up against Jan Blachowicz.

Adesanya was moving up a weight class into the light heavyweight division. Winning would make Adesanya the fourth man to be champion in two divisions simultaneously.

Adesanya put an excessive amount of his training focus on breathing techniques, working extensively with a breathing coach.
Surprisingly, he didn’t try to match Blachowicz’s weight of 205, the max weight for the division. He weighed in and fought at 200 pounds, while Blachowicz weighed in at 205 and then gained a serious amount of weight after weigh-ins3. (Weight influences fight outcomes—it’s why we have weight classes.)
Instead of gaining weight to match Blachowicz, Adesanya believed his breathing technique would give him the edge.
He said:
- “You can change the course of a fight with how you breathe. My gas tank is never going to be empty.”
- “I’m going to finish (Blachowicz) … He’s going to be breathing wrong.”
- “This is going to prove that muscles don’t win fights.” (The implication being that breathing does.)

He got tossed around and smothered by the much larger Blachowicz the entire fight and lost by unanimous decision.

Told you that to tell you this: How we breathe is just one small piece of the fitness and health puzzle. In the case of Adesanya, statistics tell us he would have been better off gaining weight and perhaps spending more training time prepping for his foe. I also contacted a UFC trainer, who agreed with that sentiment.

That is to say, we need to understand how much weight to give breathing techniques.

So let’s learn how and when nasal breathing might help our workouts and when it might limit them.

How to breathe during different workouts

Section summary:
- For strength: Pick whichever breathing you find most useful (with a caveat).
- For intense/HIIT workouts: Mouth breathing seems to be best for most people most of the time.
- For endurance workouts: Nasal breathing can act as a simple “governor” on your speed, ensuring you stay at a speed that builds your aerobic base. As you speed up, breathe through your mouth.

Strength

Takeaway: Probably a wash, although breathing deeply and holding it during “big” lifts might be beneficial.

Recall that I spoke to the research Medhdi Kushkestani. He conducted a study that tasked people with performing the bench press exercise while breathing through their mouth or their nose.

The findings: It didn’t matter. Both men and women completed the same number of reps and felt like the exercise was the same degree of difficulty with both breathing methods.

This is likely because, Medhi told me, “The main source of fuel for strength training isn’t oxygen … it’s blood glucose or the glycogen in the muscles. So it’s hard to relate breathing technique to strength performance.”

That said, certain types of breathing may be useful. The study pointed out that breathing deeply down into your belly and holding it can activate your diaphragm and stabilize your spine and torso. And that could help you avoid injury.

To do that, take a deep breath in before a big lift, like a squat, deadlift, or bench press. Hold the breath as you do your reps (you may have to “reset” midway through if you’re doing five or more reps).

Intense workouts

Takeaway: People generally perform worse when trying to breathe through their nose because intense workouts require a lot of oxygen.

One study found, “it is likely that oral (mouth) breathing represents the more efficient mode [of breathing], particularly at higher exercise intensities.”

Another from researchers at UNLV found that heart rate was higher in nose breathers during intense exercise. That’s because they likely struggled to pull in enough oxygen, limiting their performance. The scientists wrote:

Elevated HR with nasal breathing indicates increased cardiovascular stress associated with this mode.

This is where common sense kicks in: Go sprint as hard as you can or do an intense workout. Try to breathe through your nose throughout. You’ll probably start gasping for air through your mouth, because mouth breathing will give you more oxygen.4

If you try to breathe only through you nose, you’ll need to slow down—putting a governor on what is supposed to be your hardest effort5.

Cardio workouts

Takeaway: Nasal breathing can help you stay in the aerobic “zone 2.” But you’ll likely perform better by breathing through your mouth when you want to go faster.

One study found that “while breathing through the nose-only, all subjects could attain a work intensity great enough to produce an aerobic training effect.”

This suggests that breathing through your nose can act as a sort of “governor” on your effort. You can use it to ensure you’re staying roughly in the aerobic zone, or “zone 2.”

But as intensity rises, “Our body by default is going to do whatever it takes to get that oxygen in. There’s a reason our mouth drops open. It’s body survival mode,” the researcher Patrick Comer told WaPo.

The faster you go, the more oxygen you’ll need. The more oxygen you need, the more it makes sense to breathe through your mouth.

Have fun, don’t die, remember to breathe.

-Michael