Breathing through the nose while running has become one of the major topics of conversation among runners. But is it really better than breathing through the mouth? The answer depends on intensity, your training, and even environmental conditions. Here we explain what happens, when each path is advantageous, and, above all, how you can train to progressively shift from oral to nasal breathing.
There are things we do while running without thinking: moving the legs, swinging the arms, looking ahead… and breathing. Precisely because breathing is automatic, many runners barely pay attention to it until something changes. For instance, when you reach a hill and start gasping, when you try to maintain a pace beyond your capabilities, or when you run in winter and notice that the cold air irritates your throat and bronchi.
Then the question arises: am I breathing correctly?
In recent years, the idea has spread that nasal breathing is always better and that mouth breathing is a kind of technical error we should correct. But exercise physiology is a lot more interesting than that.
There is no single correct way to breathe for an entire race.
When you run very gently, nasal breathing can be perfectly sufficient and has some advantages. As you increase the pace, however, your body needs to move much more air, and it’s normal to start using the mouth as well. In fact, the spontaneous shift from nasal to nasal–oral breathing — nose and mouth at the same time — is part of the normal response to exercise. Classic studies already observed that most runners adopt nasal–oral breathing during a race, and more recent work continues to show that exclusively nasal breathing can become a limitation when exercise reaches maximal intensities.
Therefore, the question isn’t about deciding whether “nose” or “mouth” will win the battle. The correct question is another:
When is it advantageous to breathe through the nose, when do you need to use the mouth, and can you train to improve your nasal breathing capacity? The nose isn’t there by accident. The nose is far more than a simple entry point for air.
When we inhale through it, the air passes through a structure specifically designed to filter, warm, and humidify it before it reaches the lower airways. The hairs, the mucosa, and the nasal anatomy help condition the inspired air.
This becomes especially important when running in difficult environmental conditions. Think of a cold winter morning. External air can be very cold and dry. If you breathe exclusively through the mouth, a large portion of that air goes straight into the airways without first passing through the nasal conditioning system.
For some runners this is no problem at all. For others it can contribute to irritation, coughing, or respiratory symptoms, especially if there is a predisposition to exercise-induced bronchoconstriction.
That’s why it’s not unusual for a winter race to end with the classic “cough attack” at the finish line. Nasal breathing can help reduce that environmental assault because it heats and humidifies the air before it reaches the bronchi. But here comes the first major caveat. Just because nasal breathing is an excellent gateway does not mean it can always provide all the air you need.
When speed of running changes the rules
As intensity rises, the muscles require more oxygen and you need to eliminate more carbon dioxide. And here the mouth has a clear advantage: it allows moving much more air.
The oral aperture can significantly increase the air flow compared with what can pass solely through the nasal passages. That’s why, when you speed up, your body begins to open the mouth almost automatically. It isn’t that you’ve forgotten a breathing technique. It’s that your body is trying to satisfy a higher ventilatory demand.
When you are doing a very easy jog you can inhale through the nose and keep breathing under perfect control. But if you move to a fast interval, a steep rise, or the final stretch of a 10K, insisting on nasal-only breathing can become an unnecessary constraint.
A recent study in healthy subjects precisely found that exclusive nasal breathing reduced maximal oxygen consumption, maximal ventilation, and the maximum workload achieved during a graded exercise test compared with standard breathing conditions.
Another 2025 study in trained endurance athletes likewise found no significant differences in cardiopulmonary parameters and performance between oral and nasal breathing during an incremental test, although tolerance to maximal effort was numerically higher with nasal–oral breathing. The practical conclusion is simple: when you need a lot of air, using the mouth isn’t bad breathing. It’s breathing according to the needs of the exercise.
So, what is the point of training nasal breathing?
Here is where the matter becomes truly interesting. Although it doesn’t make sense to force yourself to breathe exclusively through the nose during a sprint, it can be useful to develop the capacity to maintain comfortable nasal breathing at low to moderate intensities.
Why? Because it forces you to control intensity. If you go out too fast and want to maintain nasal breathing, you’ll likely notice early that your pace is too high. The sensation of “air hunger” will appear, and you’ll have to slow down. In that sense, nasal breathing can become a kind of built-in intensity test.
If during an easy workout you can keep your mouth closed, breathe through the nose, and chat relatively comfortably, you’re probably running at a reasonable aerobic intensity.
It doesn’t mean there’s a magical speed or that nasal breathing exactly defines your training zones. But it can help you develop awareness of how your body responds.
Moreover, a scientific review on respiratory strategies applied to running concluded that nasal breathing can be useful especially during low-intensity exercise, although direct evidence on its effects on performance remains limited. And there’s something even more important: exhaling
When we talk about breathing we tend to think about inhaling. “I need to take in more oxygen.” But running isn’t just about bringing air in. You also need to expel carbon dioxide.
Every time your muscles generate energy they produce carbon dioxide as a metabolic byproduct. This travels through the bloodstream to the lungs and exits the body when you exhale. Therefore, as the intensity increases, you not only need to inhale more air, you also need to ventilate more to remove CO₂. This is one of the reasons your breathing speeds up so much when you run hard.
It also explains why attempting to take overly deep breaths all the time isn’t necessarily a solution. The goal is not to fill the lungs to maximum on every inhale, but to achieve adequate ventilation for the intensity you are working at. An efficient breath should let you both take in the oxygen you need and remove the carbon dioxide produced.
The turning point: when do we switch from nose to mouth?
What’s interesting is that the transition does not necessarily occur at a fixed speed. Each runner has their own “switch point.”
Classical physiological studies observed that subjects shifted from nasal to nasal–oral breathing as intensity increased, but the exact moment varied considerably among individuals. Among the factors related to that change were the subjective sense of breathing effort and the work required to breathe through the nose. This has a very practical application.
You don’t need to decide in advance: “From kilometer five I must breathe through the mouth.” Your body can tell you when it needs to increase the air flow.
You can begin a session breathing through the nose. As intensity rises, there will come a moment when you need to open your mouth slightly. Rather than fighting that sensation, you can use it as a reference. And here we reach one of the most interesting parts: this transition point can be trained.
How to move from mouth breathing to breathing more through the nose
If you currently run almost always with your mouth open, don’t try to change it all at once. That is probably the most common mistake.
Breathing is an automatic behavior and changing its patterns takes time. A review of strategies for runners’ breathing notes that adaptation processes can take weeks or months and that there are important inter-individual differences. The simplest strategy is to reduce intensity first.
Step 1. Start by walking
Before attempting nasal breathing while running, check what happens when you walk. For five to ten minutes, walk at a comfortable pace with your lips closed and breathe exclusively through the nose. Don’t try to take giant breaths. Breathe calmly and naturally. If you feel the need to open your mouth, slow your pace. The goal isn’t perfect breathing. It’s getting used to the sensation.
Step 2. Move to a very easy jog
In your next workout, start with a few minutes of walking and then introduce a very easy jog.
Here a fundamental rule emerges: the pace should adapt to the breathing, not the other way around. If maintaining nasal breathing requires you to run very slowly, go very slowly. It may even be necessary to alternate one or two minutes of running with one minute of walking. That’s perfectly fine.
In fact, you are doing exactly what matters: you are teaching your body to tolerate progressively greater ventilatory demands without immediately resorting to oral breathing.
Step 3. Find your comfortable nasal pace
After several sessions, try to identify the maximum pace at which you can still breathe comfortably through the nose. That will be your nasal reference pace. It does not have to match your usual easy pace. It may be considerably slower.
Keep that pace for blocks of five, ten, or fifteen minutes, depending on your level. A review of breathing strategies in runners precisely proposes starting by slowing down until you find a stable intensity at which nasal breathing feels comfortable and using that pace as a starting point for progression.
Step 4. Approach gradually the “air hunger”
This is the most interesting part of the process. Once you can run comfortably while nasal-breathing, slightly increase your pace. Not too much. Just enough to notice that breathing begins to demand more.
There will come a moment when a familiar sensation appears to every runner: you want to take a deeper breath and open the mouth. It’s the so-called sensation of air hunger. You don’t need to fight it. You can stay a few seconds or a short period near that limit and then return to a slower pace. Over time, that point can shift. What initially forced you to open your mouth at a given pace may cease to do so after several weeks of practice. The idea isn’t to hold your breath. The idea is to gradually increase the intensity you can tolerate while keeping nasal breathing comfortable.
A simple starter workout
If you want to try it, you can insert this session one or two times a week within your easy runs:
10 minutes: walk and very light jog, nasal breathing.
10 minutes: easy run exclusively nasal.
5 minutes: increase the pace slightly until you approach the point where you get air hunger.
2-3 minutes: slow back down and recover nasal breathing.
5-10 minutes: very easy run or walk to finish.
You don’t need to make your entire training nasal breathing.
In fact, you shouldn’t sacrifice the quality of a hard session just to keep your mouth closed.
If you have to do intervals, hills, or a race-pace workout, use the breathing you need.
nasal breathing can be trained particularly well on easy runs.
How long does it take to achieve this?
Here it’s wise to forget about quick promises. There isn’t a magic number of days. Adaptation depends on how much you run, at what intensity, how long you’ve been training, your tolerance for the CO₂ sensation, and your nasal anatomy, among other factors.
The literature analyzing breathing strategies in running places the adaptation periods studied from several weeks to several months.
Additionally, a recent study in recreational runners used a four-week program of respiratory exercises and nasal breathing during low-intensity sessions. It improved apnea time but did not produce differences in VO₂max or maximum exercise time with nasal breathing compared to the control group.
This is important because it keeps expectations grounded.
Training breathing can be useful, but it is not a magical shortcut to boost performance.
Your running training remains the main piece.
And respiratory exercises?
They can have their place.
Specific training of the respiratory muscles carries evidence of possible improvements in the strength of the respiratory muscles and certain performance parameters in athletes, although results depend on the protocol used and not all exercises have the same support. A systematic review and meta-analysis published in 2025 found benefits of respiratory muscle training in different variables related to respiratory function and performance.
But beware of turning any breathing exercise that appears on social media into a mandate.
Breathing harder does not necessarily mean breathing better.
And there is no need to deliberately hyperventilate during a race to “train the lungs.”
If you want to work specifically on the respiratory muscles, the most sensible approach is to use established protocols and, if there is any respiratory pathology, to do so under professional guidance.
Do nasal strips help?
They can improve the sensation of air passage for some people, but don’t expect them to transform your performance on their own.
A systematic review and meta-analysis on nasal dilators found some favorable results in parameters such as VO₂max and perceived effort, but the overall certainty of the evidence was very low.
That is to say: if a nasal strip makes you feel you breathe better, great. But we should not confuse that sensation with a guaranteed performance improvement.
And if you have persistent nasal congestion, allergies, a deviated septum, or another problem that makes nasal breathing difficult, the reasonable course is to address that cause first.
Should we breathe through the nose during a race?
Not necessarily.
Imagine a marathon.
The first kilometers can unfold at a relatively comfortable intensity, and you may be able to use nasal breathing quite a bit. As the pace increases, especially if you’re racing, oral–nasal breathing is likely to appear.
That doesn’t mean you’ve “failed.” It means the ventilatory demand has risen. It can occur even earlier on a steep climb.
And during a final sprint, trying to maintain exclusively nasal breathing may become a limitation.
The available research precisely supports this flexible view: nasal breathing can be beneficial at low and submaximal intensities, while oral–nasal breathing better meets ventilatory demands as intensity rises.
The golden rule: let breathing adapt to training
Think of your breathing as a tool, not a creed.
Easy run: try to breathe mostly through the nose if it feels comfortable.
Moderate run: nasal or nasal–oral breathing can be used according to your needs.
Tempo, hills, and intervals: let the intensity determine how you breathe.
Sprint or race finish: use whatever airways you need.
And remember that external conditions also matter. Cold, dry air, allergies, or congestion can make nasal breathing more difficult and the mouth necessary earlier than usual.
What if I’m running out of air too much?
Here there isn’t a remedy for everything through breathing techniques.
If the shortness of breath is disproportionate to the effort, recurs frequently, is accompanied by wheezing, coughing, chest tightness, or worsens with exercise, you should consult a health professional.
Exercise-induced bronchoconstriction is one possible cause of breathing difficulty in runners and can be particularly problematic with cold, dry air.
In these cases, learning nasal breathing can be a helpful supplementary tool, but it does not replace diagnosis or appropriate treatment.
