Should I Breathe Through My Mouth or Through My Nose?

A pulmonary medicine specialist explains what's best
man breathing through mouth after exercising

Q: What’s the right way to breathe? Is it through my mouth or my nose?

A: You’ve probably been told in certain situations to “breathe in through your nose and out through your mouth” — especially during exercise or meditation or to relax. But ever wondered why? 

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The important part of the answer is really the first part —  breathing in — and what happens along the way.

Humans are naturally designed to breathe through our noses from birth. It’s the way we’ve evolved, and there are reasons we default to nasal breathing. 

Inhaling through your nose offers many more benefits to your body than taking in air through your mouth. 

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When we’re newborns, we breathe in and out through our noses almost all the time. This is related to how our throats are configured, so we can breathe and suckle at the same time without choking. It’s a survival mechanism.

Our noses are also designed to process the air that comes in very differently that our mouths can. These are intentional and functional parts of our body’s design to keep us safe and healthy. 

Here are all the good things your nose does that your mouth doesn’t when you breathe in:

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  • Temperature control. Your lungs aren’t huge fans of air that’s too hot or cold. Unless you have an obstruction (like a deviated septum or chronic rhinitis), your nasal passageways will warm (and sometimes cool when needed) the air to your lungs. Your mouth doesn’t have a way to do this. For example, winter runners who breathe deeply through their noses get warmed air without sending a chill to their lungs, versus those who breathe with their mouths.
  • Filtering. The cilia in your nose passageway filters out debris and toxins in the air and sends them directly down your throat instead of your lungs. (Gross, but intentionally better in your stomach than anywhere else.) Mouth breathing sends whatever’s in the air directly into your lungs.
  • Humidifying. The passages in your nose are specifically designed to humidify the air you breathe, something not present in your mouth. Ever wake up after a restless night’s sleep with dry mouth or sore throat? Chances are, you’re fighting nature by mouth-breathing, and you’re not getting the humidifying or moisture-balancing benefits of nasal breathing.  
  • Smell. Using your sense of smell through the olfactory system that’s mostly present in your nose can help you detect harmful toxins in the air and in food.
  • Attraction. Using your nose to breathe also can kick in your ability to smell pheromones, perspiration and other odors that help you find a mate. You may not find these benefits while running with just your mouth open. 

Just something to think about next time you’re out and about on a run.

The only time you really need to temporarily resist natural nose breathing and engage in mouth-breathing is when you’re doing strenuous exercise and need more air to your lungs more quickly, or when your nasal passage is blocked due to congestion, allergies or a cold. But remember, this does however cancel most the benefits that breathing through your nose provides.

— Pulmonary medicine specialist Jason Turowski, MD 

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