Julie Hill started exploring nasal breathing because of her allergies. Every spring, year after year, they worsened; dry, irritated eyes that doctors couldn’t offer her any meaningful solutions for. To add gas to the flame, she says, she talks for a living and loves to run, ride, and train outside.
Hill, a functional breathing and movement coach with her own business based in Colorado, started with how she consumed oxygen most of the time, which like most people, tended to be through her mouth.
Breathing, unlike consuming water or fuel, can be done through the nose or the mouth, but it’s often the latter, especially when we’re exercising. Though nasal breathing can feel constrictive, new research is showing that breathing through your nose is more effective than through the mouth at delivering oxygen throughout the body, and it delivers a slew of other benefits too.
“The nose is designed for breath,” said Hill. “The mouth is there more for communication and eating, but it’s a backup, right?”
Why mountain bikers might want to limit mouth breathing
The benefits of nasal breathing are multi-faceted and can influence your facial and jaw development, sleep patterns, teeth and gum health, and more. At its base level, nasal breathing treats the air you’re consuming, heating, humidifying, and filtering it, unlike oral breathing.
For mountain bikers, some of the greatest benefits lie in oxygen uptake and circulation. Who doesn’t want to feel a little less tired when we’re pumping up a steep trail?
While oral breathing may make for more voluminous inhalation, oxygen likely travels farther into the lungs when it’s brought in through the nose.
A 2018 study took a group of recreational runners and created a control group for oral breathing and measured the performance difference between those and nasal-adapted runners, finding that there was a small difference in VO2 max (the max amount of oxygen one can use during intense exercise) but that nose breathers demonstrated a much lower mean ventilatory equivalent, or the ratio of volume of carbon dioxide (CO2) expired per minute to the volume of oxygen consumed per minute.
In this particular study, researchers sought to examine the effect of prior training and adaptation to nasal breathing on cardiovascular ability at peak levels and anaerobic energy contribution. The participants trained and raced for a minimum of six months allowing themselves to adapt to nasal breathing and completed exercise tests designed to elicit a max workload and oxygen uptake within six to ten minutes on a treadmill. Researchers increased the workload by .3MPH every 30 seconds until the runner reached a point of voluntary termination. The times were recorded.
Then, ten minutes after, the subjects completed a six minute steady state protocol at 85% of their achieved max velocity. Mouth breathers wore a swimming nose clip and nose breathers used a medical mask with their mouths taped shut.
In the first procedure, the subjects “exhibited no significant mean difference” between their peak lactate production or VO2 max and no differences in resting or peak heart rate between trials.
The overall conclusion was that runners who used a nasally-restricted breathing pattern at different intensities demonstrated a “small performance improvement (through nasal breathing) by improving one’s physiological economy (or your ability to run faster while using less energy breathing).”
Basically, nasal breathing athletes don’t have to work as hard to get the equivalent oxygen because nasal breathing is more effective at getting oxygen into the blood stream.
“In this study, the mean reduction in oxygen consumption during nasal breathing while running at 85% of the velocity at VO2 max was approximately 4%,” which contrasted with another study from 2017 which studied cyclists and found that nasal breathing was more efficient though oral breathing can be more effective at higher intensities.
As mentioned above, nasal breathing allows for better filtration, temperature regulation, and the humidification of the air being consumed, mitigating problems with breathing in unfiltered air. This tends to create problems for people who suffer from exercise induced asthma, said Hill, which also affects some mountain bikers. If you’ve ever suffered a post-ride cough, focusing on the nose may help reduce this too.
But perhaps the greatest potential benefit for cardio enthusiasts is improving oxygenation by the release of nitric oxide, a vasodilator. Oral breathing doesn’t allow this to happen. When you release nitric oxide, it dilates your blood vessels, effectively making it easier to transport blood and oxygen throughout the body.
“Nasally restricted breathing improves oxygenation locally through the release of nitric oxide, a potent vasodilator, and through increased serum carbon dioxide: a competitive binder of hemoglobin with oxygen, thereby resulting in increased O2 release from hemoglobin at the active tissues,” writes authors of the 2018 study.
Nasal breathing maintains an increased level of CO2, one of the gases exchanged in the respiratory process. The higher level of CO2 causes the bond between hemoglobin and oxygen to weaken, known as the Bohr Effect. This makes oxygen more available to the tissues, said Hill.
How to adapt and overcome “air hunger”
Hill and researchers describe the challenges of nasal breathing during exercise, or the feeling that you just can’t get enough oxygen through the nose alone as “air hunger.” The nasal passage is a straw compared to the hose of a mouth, and when intensity increases, it can feel like it’s impossible to get enough air into your lungs with your nose alone.
“It takes a lot of awareness and focus because you’re going to want to switch to your mouth,” said Hill.
The 2018 study noted that “the majority of individuals will spontaneously switch from predominately nasal breathing to predominately oral breathing” under circumstances like this, adding that when this point is reached, it is suspected it’s because of the increased work of breathing or an indirect effect of hypoventilation.
Hill said the same thing in our conversation. Try to maintain nasal breathing for as long as possible on rides but it is fine to switch to oral breathing when the ride gets harder.
It can takes weeks to adapt to nasal breathing as the study suggests and Hill recommends that cyclists take it easy when they’re starting. Hill began by concentrating on nasal breathing during chores or dog walks. Her advice is to slow down, take deep breaths and suspend the breath for a moment or two between inhales and exhales.
Relax your jaw, seal your lips and rest your tongue on the roof of your mouth. As you incorporate nasal breathing on mountain bike rides, start on flat spots or mellow climbs and switch back to oral breathing when needed. Riders can still gain the oxygen uptake benefits of nasal breathing training this way. But, if you want to make the biggest gains, you’ll need to reel in your pace, Hill said.
“If you really want to change it faster, you’re going to be more of a purist and let your body slow down enough on your ride to where you can stay with it.”
When Hill started adapting to nasal breathing, she noticed her nose running more, which is a good sign, since it meant her filter was working, she says. Your sleep could also quickly improve. Hill is excited that nasal breathing has gained recognition in recent years. Writer and journalist James Nestor’s book Breath, which explores the “lost art” of breathing has gained a lot of press and recognition for bringing attention to something people have largely forgotten or ignored, an oversight that has led to increased sleep apnea, asthma, and allergies.
“This is just an area that is so unexplored,” Hill said. “Our respiratory system impacts every other single system in our body. I don’t think people think that way.”
