Nose or mouth: which should you breathe through?

What your nose does to the air

Your nose is more than an entrance. According to Cleveland Clinic, it warms, conditions and filters the air you breathe. The hairs inside trap dirt and dust. Cilia, tiny hairlike structures, trap smaller particles.

Inside your nose are folds called turbinates. They warm and moisten the air after you breathe it in, so it travels more comfortably into the rest of your airways.

Your mouth doesn't do that job the same way. That's why it dries out when you breathe through it for a long time.

Nitric oxide: a gas your nose makes

In the 1990s, a research group in Stockholm found that the air in the nose contains nitric oxide, a gas the body uses, among other things, to relax blood vessels. In a 1999 review, Lundberg and Weitzberg concluded that its main source in healthy adults is probably the paranasal sinuses, the cavities around the nose.

When you breathe in through your nose, some of that gas travels with the air toward your lungs. In a small 1996 study, six of eight healthy people had a through-the-skin oxygen reading about 10% higher while breathing through the nose than while breathing through the mouth.

It's an interesting finding from very few people. It isn't enough to say that nose breathing improves your health by this route. It's one more reason, not a promise.

When your mouth has its place

• During hard effort. When you're running to catch the bus, your body wants more air than fits comfortably through your nose. Opening your mouth is normal.
• When your nose is blocked. A cold, allergies or sinusitis can close things off. Breathe however you can.
• For some exhales. The UK's National Health Service (NHS) teaches its calming exercise with the inhale through the nose and the exhale through the mouth. On this site, 4-7-8 breathing and Cyclic sighing breathe out through the mouth, and other patterns let the air out through pursed lips.
• When you speak and sing. Your voice rides on the air you breathe out through your mouth.

Breathing through your mouth all the time

It's a different matter when your mouth is your only route. Cleveland Clinic explains that most people who breathe this way do it because they can't get enough air through the nose: congestion, a deviated septum, enlarged turbinates or tonsils, polyps.

The signs it mentions include dry mouth, bad breath, hoarseness, snoring, drool on your pillow and feeling tired all the time. It doesn't consider it a serious health issue for adults, but it suggests talking to a provider if you notice those signs.

Mouth taping for sleep

Social media has spread the idea of taping your mouth shut to force nose breathing while you sleep. A 2025 systematic review in PLOS One pulled together 10 studies. It concluded that the data don't support the practice as an intervention for breathing problems during sleep, and that where improvement did show up, it was small and limited to mild sleep apnea.

It also warned of potentially serious harm for anyone with a blocked nose. If your nose won't let air through, closing your mouth doesn't fix that. This site doesn't recommend it. If you're curious, that's a conversation to have with a health professional.

In your practice

On this site, unless a pattern says otherwise, you breathe through your nose, in and out. That's how 4-6 breathing is designed, for example. Alternate nostril breathing (nadi shodhana) takes it a step further and uses one nostril at a time. In Bhramari, the bee breath, you breathe out with a hum, lips closed.

A 2018 review of slow breathing proposed that some of its effects might come from receptors in the nose that sense air moving past. That's a hypothesis, not yet confirmed.

If your nose is stuffed up today, breathe through your mouth without guilt, or save the practice for another day. And if you can almost never breathe well through your nose, an exercise won't fix that: get it checked.