Should you breathe through your nose during exercise? What the research shows

You can breathe through your nose during easy and moderate exercise, and most healthy people can keep it up at fairly hard efforts too. Whether it improves performance is far less clear. The studies are small, and at maximal effort, breathing through both your nose and mouth is normal and fine.

When do people switch to mouth breathing?

A 2022 review in Frontiers in Physiology on breathing strategies for running notes that humans usually switch from nose to mouth breathing once ventilation rises above about 40 litres of air per minute. That's why mouth breathing during exercise is often assumed to be necessary.

The same review points out that people have more flexibility than that suggests. It cites a 2009 study in which people kept breathing through their nose up to 85% of their VO2max, after only a familiarization session. VO2max is the maximum rate at which your body can use oxygen, and it's a common measure of aerobic fitness.

Is nose breathing good for exercise?

Nose breathing can be good for easy and moderate exercise, because the nose does real work on the way in. The 2022 review describes it as built to humidify, warm and filter the air you breathe, and notes that nasal breathing increases nitric oxide in the airway. Mouth breathing skips those steps.

That matters more in some conditions than others. The 1995 study discussed below explains the reasoning: drying and cooling of the airways is thought to be the main trigger for exercise-induced asthma, and nose breathing reduces that drying and cooling compared with mouth breathing. The 2022 review suggests nasal breathing may be especially useful in cold, dry or high-altitude conditions, and recommends it for low-intensity exercise because of its effects on the airway. If you want the background on what the nose adds, see nitric oxide and nasal breathing and nasal breathing vs. mouth breathing.

What happens to performance with nose-only breathing?

The best-known early study, published in 1995, tested 20 healthy, regularly active adults aged 18 to 55 who had no nasal obstruction. Breathing through the nose only reduced their maximal ventilation and their maximal oxygen uptake compared with breathing through the mouth or through both. The drop in ventilation was three times larger than the drop in oxygen uptake.

The authors also found that while breathing through the nose only, every participant could still exercise hard enough to produce an aerobic training effect. So nose breathing didn't stop people training, but it did cap their top end in that test.

Can you adapt to nose breathing?

Runners can adapt to nose breathing, according to a small study. A 2018 study looked at 10 recreational runners, five men and five women, who had trained using nose-only breathing for at least six months. In a maximal treadmill test, they showed no significant difference in VO2max, time to exhaustion or peak lactate between nose and mouth breathing. Breathing through the nose, they moved less air for the same oxygen uptake, which the authors described as superior physiological economy.

This is an interesting result, but it has limits. The study was small, the runners had chosen nose breathing themselves, and it compared them at one point in time. It doesn't show that anyone who switches will get the same result, or how long adapting takes.

The 2022 review gives some sense of the timescale. It says anecdotal reports suggest 10 to 12 weeks for nasal breathing to feel meaningfully more comfortable, while studies have examined practice periods of up to six months. It also makes an encouraging point. Nasal airway resistance falls during exercise whichever way you breathe, and some reports show it dropping within days or even minutes of nose breathing. In the review's words, performing it encourages subsequent ease.

How do you start training with nasal breathing?

To start training with nasal breathing, build up gradually. There's no tested protocol, so treat this as a sensible way to apply the research rather than a programme:

1. Start with walks and easy runs or rides, at a pace where nose breathing feels comfortable. In the 2009 study cited by the review, people kept nose breathing up to 85% of their VO2max.
2. When you can't get enough air through your nose, let your mouth open. That's the signal you've gone past your current nasal ceiling, not a failure.
3. Keep it up over weeks rather than days. The adapted runners in the 2018 study had practised for at least six months.
4. Keep intervals, races and maximal efforts as nose-and-mouth sessions.

The 2022 review also mentions humming on the out-breath, a technique from yoga, which it says can increase nasal nitric oxide up to 15-fold at rest. Whether that helps during running hasn't been studied properly. If you'd like some breathing practice off the track, nasal breathing exercises has a few to try.

Should you mouth breathe during hard exercise?

Breathing through your mouth as well as your nose is normal near maximal effort. A 2025 randomized cross-over study tested 12 well-trained male cyclists and triathletes in a maximal exercise test using three breathing modes: mouth only, nose and mouth together, and nose and mouth with a decongested nose. It found no significant differences between the three in heart and lung measures or performance.

Time to exhaustion was 2.8% and 4.2% longer with nose and mouth breathing, and with the decongested nose, compared with mouth only. Those differences weren't statistically significant, so treat them as a trend rather than a finding. Blood lactate was lower after the test in the mouth-only condition. The authors suggested that keeping the nose involved, particularly when it's clear, may be more helpful for sustaining endurance, which fits with the idea of not clamping your nose shut when you go hard.

The 2022 review also notes that nasal breathing during heavy exercise has been linked to a higher heart rate with no difference in power output or anaerobic performance. And the 1995 study shows the ceiling it can put on maximal effort.

Should you breathe through your nose when running?

Breathing through your nose when running works well at easy paces, based on a reasonable reading of the evidence. During easy runs, walks, rides or warm-ups, breathing through your nose is something most people can do comfortably, and it keeps the nose doing its usual job of warming and filtering air. If you want to train this way, building up gradually makes sense given how the adapted runners in the 2018 study had practised for months.

During intervals, races and anything near your maximum, let yourself breathe through your mouth as well. None of the studies here showed a performance gain from forcing nose-only breathing at maximal effort, and the 1995 study showed a loss.

If you find you can't breathe comfortably through your nose even at rest, that's worth looking into before you try to train with it. The nose test is a quick way to check, and why is my nose stuffy at night? covers common reasons a nose feels blocked.

Do nasal strips help when running or exercising?

Nasal strips can make nose breathing easier during exercise, which is why some athletes wear them. In a small 1999 study of nine healthy adults, nasal strips cut resting nasal resistance by about a third. During a progressive exercise test, people kept breathing through their nose about 15% longer before switching to the mouth, and reached about 15% more airflow through the nose before they switched. The authors concluded that strips do promote nasal breathing during exercise, though the delay was relatively small.

What strips don't seem to do is boost fitness numbers. A 2021 meta-analysis of studies in healthy people found no improvement in VO2max, heart rate or perceived effort with a nasal strip. So think of a strip as a comfort tool that helps you stay nose breathing for longer, not a performance aid. We cover the details in nasal strips for exercise, and how to apply nasal strips helps with getting a good fit when you're sweating.

Does nose breathing during the day carry over to sleep?

There's no research showing that daytime nose breathing carries over to sleep directly. But if you're working on nasal breathing in training, it makes sense to look at the hours you spend asleep too, when it's much harder to notice whether your mouth has fallen open. Why do I breathe through my mouth at night? covers the common reasons, and for adults with a clear nose, what is mouth taping? explains how tape keeps the lips closed overnight. For a wider look at the topic, see our nasal breathing hub.

If you want to try nasal strips, our pick is TitanAir Nasal Strips.

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.