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On the importance of nasal breathing during exercise

“There was a footrace in Sparta each year among the boys. They ran ten miles, barefoot, carrying a mouthful of water. The boys were not allowed to swallow any of the water but had to spit it all out at the end of the race.”

-”The Warrior Ethos” by Steven Pressfield

A number of Native American tribes such as the Apache trained young boys by making them run long distances with a mouthful of water and they also had to spit it out at the end, just like the Spartans. The Rarámuri are a legendary tribe of distance runners from the Copper Canyons in Mexico who can run more than 60 miles in a day, and they run these vast distances all while breathing through their noses. Could you run for hours while only breathing through your nose? You absolutely could, with a little practice, and

there are huge benefits that come from exercising with your mouth closed. When you’re at the gym, take a look around at your fellow gym-goers. Whether they’re running, rowing, cycling, or lifting weights, you’ll notice that most of them are mouth breathing. Sure, it seems normal because everyone is doing it. When you work out you feel short of breath and you can get a lot more oxygen by breathing through the mouth, right?

Unfortunately, this is not right. You can certainly get a larger volume of air from bigger breaths, but this doesn’t translate into your body getting more oxygen at the cellular level. In fact, it translates to the opposite – your body ends up with less oxygen at the cellular level because you’re over-breathing and reducing carbon dioxide levels, which in turn decreases the cellular absorption of oxygen. Carbon dioxide plays a vital role in the body; it’s the catalyst for oxygen to be released into the cells.

This is explained by the Bohr effect, a physiological phenomenon that is defined as a decrease in the amount of oxygen associated with hemoglobin and other respiratory compounds in response to a lowered pH resulting from an increased concentration of carbon dioxide in the blood. In simpler terms, hemoglobin releases oxygen more easily as carbon dioxide levels in the blood increase. Your pulse oximeter could read 99% or 100% and it wouldn’t tell you anything about how much of that blood oxygen is actually being delivered into cells – for that, you’d need to know your carbon dioxide levels as well.

Breathing through the nose slows and decreases the volume of air moving through the lungs, allowing us to retain more carbon dioxide and thus increase oxygenation at the cellular level. The nose adds moisture and warmth, and filters the air being introduced to the lungs, which allows for a greater absorption of oxygen in the lungs. The nose also adds NO, nitric oxide, to the inhaled air. Nitric oxide increases the levels of carbon dioxide in the blood, which in turn increases the amount of oxygen being delivered to the cells. Nitric oxide is also a potent vasodilator, which means that it widens blood vessels, improving circulation and the delivery of oxygen all over the body.

This effect is particularly helpful in the blood vessels of the lungs, facilitating more efficient gas exchange and further increasing the delivery of oxygen to the body's cells. Nitric oxide is also a potent antiviral, antibacterial, and antifungal, helping to sterilize the air, acting as a defense against infection. In addition, nitric oxide helps your muscles get stronger and recover faster, which is why supplements that boost NO have been very popular in the fitness industry. Due to the combination of all of these factors, nasal breathing increases oxygenation by ten to twenty percent.

In addition to all the previously mentioned benefits, nasal breathing encourages healthy changes to the body’s biomechanics and biochemistry. Nasal breathing tends to result in abdominal breathing, drawing air deeper into the lungs. Due to gravity, the lower lobes of the lungs have a higher concentration of blood and thus they can absorb more oxygen. Belly breathing also stimulates your vagus nerve, signaling the parasympathetic, rest and digest, nervous system to become active, helping you to relax during exercise, resulting in lower blood pressure, lower heart rate, and less stress overall.

Breathing through your mouth stimulates the sympathetic, fight or flight, nervous system, creating much more tension and stress in the body. While breathing through the nose is best, for some elite athletes it will not be possible to breathe through the nose all the time. Nasal breathing can be maintained while working at 90-95% capacity, but beyond that the mouth will need to be employed.

My advice to elite athletes is breathe through your nose as much as you are able to in training and competition, and make sure you're breathing through your nose in your daily life and during sleep, but when you need to turn on the afterburners, open up your mouth!

For the rest of us, there’s no reason we should be breathing through our mouth while we’re exercising, or any time other than a life-or-death situation.

If you’d like to read a study that suggests runners can increase their distance and speed by switching to nasal breathing, click the following link.

Thank you for reading and feel free to reach out with any questions or comments.


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