How often do you think about your breath? Maybe only when you’re out of it, as you chug through that final hill repeat, or huff and puff across the finish line of a race. But, according to some research, you should think about shutting your mouth and breathing through your nose through the duration of your runs.

That’s the idea behind nasal breathing—running with your mouth closed and relying solely on your nostrils to deliver oxygen. Most of us use our mouth to breathe while running, helping us gasp for more air. But science actually says that nasal breathing is more efficient at delivering oxygen. So could it improve performance?

Nasal Breathing and Your Running Performance

Nasal breathing may provide a small performance benefit based on a study in the International Journal of Kinesiology and Sports Science in 2018.

The study followed 10 runners for six months and compared their maximum oxygen intake rates of nasal versus mouth breathing. “We have demonstrated the potential for a small performance improvement (through nasal breathing) by improving one’s physiological economy (or your ability to run faster while using less energy breathing),” says lead author George Dallam, Ph.D. professor in the School of Health Science and Human Movement at Colorado State University, and former inaugural national teams coach for USA triathlon, who has researched the effectiveness of nasal breathing.

The study found that through nasal breathing, the athletes didn’t have to work as hard to get the same amount of oxygen, despite taking fewer breaths per minute. Why? The research suggests that with a slower breathing rate (nasally) the oxygen is more effective at getting to the bloodstream.

Dallam says the most common misconception about nasal breathing is that it can’t provide enough ventilation (or air flow) to support intense exercise. The act of ventilation requires 15 percent of the total energy necessary to run a hard effort, he says. Nasal breathing reduces total ventilation at a given high workload by about 23 percent, thus reducing overall energy consumption by 2 to 3 percent, as they found in the study. That means even if ventilation is lower, so too is the amount of energy you need to work.

How (and Why) Nasal Breathing Works

Dallam says when we breathe orally, we breathe more quickly, thus we take in more breaths. However, when we breathe nasally, we are slowing down our breathing. Although we may not be taking as deep a breath, the air likely penetrates the lung further. “Breathing nasally requires us to overcome more resistance to pull air through the filtering apparatus of the nasal cavity,” he explains. “This likely transfers more momentum to the air driving it more deeply into the lung, even when the size of the breath is the same as when breathing orally.”

Dallam says to think of the mouth versus nose breathing in terms of trying to open a stuck door, compared to one that opens easily. “When you pull harder on the stuck door you are more likely to fall backwards as the greater pulling force transfers back to your body. In the lungs, this greater force activation while breathing nasally also recruits the diaphragm muscle (at the base of the lung) more successfully so the entire lung is expanded versus primarily the upper portions, which might also favour air penetrating more deeply with each breath.”

In other words, the force required of a nasal breath better penetrates the entire lung, giving you a more efficient means of oxygen delivery.

What does this mean for you? Essentially when you’ve adapted to nasal breathing you’re taking about five to six fewer breaths per minute. As a result, you can improve your running economy by about 1 to 2 percent. “What we often forget is that breathing requires muscle activity and energy to occur, so the more we have to breathe at any rate of running the more energy that has to go to that process” Dallam says.

How to Start Nasal Breathing While Running

Transitioning to nasal breathing won’t happen overnight—it takes time to adjust. And don’t gauge the ease of it based on your first run, either. “It’s normal to feel air hunger and it will take some time to adapt to,” Dallam says.

He advises giving yourself small increments of running to adjust. For example, try running for 30 to 60 seconds breathing nasally, then rest. Or consider slowing down your running pace until you feel comfortable running and breathing nasally. As you get more comfortable breathing nasally your pace will begin to increase. Small progressive steps will help you adapt to nasal breathing overtime.

If you’re a mucous-heavy runner, that’s okay too. Your body will, in time, adapt. In other words, you won’t continually feel like you are blowing a lot of snot out of your nose. You might also want to consider a nasal strip while running (an adhesive bandage placed on the bridge of the nose that helps to fully open up your nasal passages). And of course, if you’ve had problems with breathing nasally because of an injury, consult your doctor before starting nose-only breathing.

How to Practice Nasal Breathing When You’re Not Running

“You’re usually breathing through your nose when you’re calm and nasal breathing helps you have more control over your energy,” says Belisa Vranich, Psy.D., breathing expert.

Having a strong breathing practice doesn’t have to end when you are finished running, either. Vranich says your most natural breath is nasally. “Staying with nasal breathing is good because it is easier to extend the exhale and it makes you focus on the breath.” So it might be smart to consider the benefits of calm, controlled, and conscious breathing throughout your entire day, not just when you lace up.

A Nasal Breathing Exercise To Get You Started

Alternate nostril breathing or Nadi Shodhan Pranayama (translates to: energy cleansing breath) is a common breathing technique used in yoga and meditation classes and is easy to learn and practice. You’re simply inhaling through one nostril and exhaling through the other. Alternate nostril breathing can help focus and energise the mind, and will help you become more comfortable relying on breathing with just your nose.

How to do it: Start seated. Place left hand on left thigh, and bring right hand to face. Rest pointer and middle finger between eyebrows, and place thumb and ring finger near nostrils. Gently close right nostril with thumb, and inhale through left nostril, hold the breath and left nostril closed for a moment and then release thumb and exhale breath through right nostril. Pause. Now inhale through right nostril. Use thumb to close right nostril, hold the breath and both nostrils closed again for a moment then release the breath through the left nostril. Work to have the duration of your inhalation match your exhalation and repeat 5-10 cycles.

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