Her Trails Coaching

Nasal Breathing for Ultra Runners
A Useful Tool, Not a Rule

Nasal breathing can be a valuable way to stay connected to easy effort, particularly on base runs, recovery runs, warm-ups and easy hiking. But it is not a badge of fitness, a shortcut to endurance, or something you need to force through every session.

Think of it as a pacing and awareness tool. When nasal breathing is comfortable, it is usually a good sign that your effort is genuinely easy. When it becomes strained, noisy or requires you to tense your face, neck and shoulders to maintain it, your body is giving you useful information: the work has likely moved beyond your easy aerobic range, or the conditions no longer make nasal-only breathing practical.

The aim is not to win by keeping your mouth shut. The aim is to learn how easy effort should feel, and to make calmer pacing decisions because of it.

The Case For

What Nasal Breathing Can Offer

Your nose filters, warms and humidifies the air before it reaches your lungs. This can feel particularly helpful in cold, dry or dusty conditions.

For training, its more useful role is behavioural. Nasal breathing naturally limits the amount of air you can move compared with breathing through both nose and mouth. At easy effort, that limitation can stop a run quietly drifting from easy to moderate. It gives you an immediate, body-based check on whether you are actually running the session intended.

This matters in an ultra program. Base running is where you develop aerobic capacity, durability and time on feet without creating a recovery cost that undermines your harder sessions or long run. If every easy run gradually becomes a little too hard, the cumulative load becomes harder to absorb. Nasal breathing can be one simple guardrail against that creep.

It can also give you a reset when you are rushing: at the start of a run, after a climb, when your mind is busy, or when you notice your shoulders rising and your breathing becoming shallow.

The Limits

What It Does Not Do

Nasal breathing is not a superior breathing method at every intensity. As pace, heat, gradient or fatigue increases, your body needs to move more air. Mouth breathing, or breathing through both your nose and mouth, is a normal and appropriate response. Trying to stay nasal-only during intervals, hard climbs, hot conditions or racing can make the session more stressful than it needs to be.

It is also not a reliable standalone measure of fitness. Nasal congestion, allergies, a deviated septum, illness, pregnancy, cold air and anxiety can all change how easy it feels on a given day.

The goal is always appropriate breathing for the work you are doing, not adherence to a technique.

Use It Here

When Nasal Breathing Serves Your Training

Use it where the purpose of the run is genuinely easy aerobic work.

On these outings, you might breathe fully through your nose for a few minutes at a time, then return to natural breathing. Or, if it is comfortable, maintain nasal breathing for much of the run. It should feel quiet and relaxed, not like you are rationing air.

Let It Go

When To Let It Go

Let your breathing open naturally when the session requires more. That may be during:

For most runners, a blend of nose and mouth breathing is completely normal as effort rises. Rather than forcing nasal-only breathing, focus on staying relaxed through your jaw, shoulders and hands, and on allowing a full exhale.

Getting Started

How To Use It On Base Runs

Start small. Choose one or two easy runs each week and use nasal breathing for the first 10 to 15 minutes, especially if you tend to start too quickly. Then experiment with it on gentle climbs or during relaxed hiking sections. If you need to open your mouth briefly, do so. Rather than seeing that as failure, use it as feedback: perhaps the hill is steeper, the pace has crept up, or your body is carrying fatigue.

A simple progression could look like this:

Avoid breath-holding, exaggerated deep breaths or trying to slow your breathing unnaturally while moving. Let the breath stay soft and responsive to the terrain.

Race Day

Nasal Breathing On Race Day

Race day is not the time to make nasal-only breathing a rule. Instead, use it as a check-in tool early in the race. If you can breathe through your nose comfortably on easy runnable terrain or while hiking, there is a good chance you are beginning with appropriate restraint. If you are already fighting for air on a section that should be easy, that is useful information: settle your pace before the race starts costing more than it should.

Nasal breathing can be especially useful:

As the race becomes harder, let go of the idea that you need to maintain it. Breathe in the way that allows you to move efficiently, fuel well and stay composed.

Beyond Running

Integrating It Into Everyday Life

The most useful everyday practice is not obsessive monitoring. It is simply creating a few moments where you notice and soften your breathing. Try one or two of these:

If you regularly struggle to breathe through your nose, snore heavily, wake unrefreshed, or experience wheeze, chest tightness or unusual breathlessness with exercise, speak with a GP or relevant clinician rather than trying to train through it.

Evidence note: the research on nasal versus oral breathing during exercise is still developing. Nasal breathing can reduce ventilation at submaximal effort, but it should not be presented as a universal performance advantage, particularly at higher intensities.