# What's the "harm," if any, in breathing through one's mouth? **URL:** \ **Category:** Factual Questions\ **Created:** [November 21, 2009, 1:05am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359 "2009-11-21T01:05:33Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Leaper](https://avatars.discourse-cdn.com/v4/letter/l/4bbf92/32.png) [@Leaper](https://boards.straightdope.com/u/Leaper)\ **Post date:** [November 21, 2009, 1:05am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/1 "2009-11-21T01:05:33Z")
(Please, no mouthbreather jokes; it’s just too predictable. :D) Something I’ve always wondered: what harm, if any, is there in breathing through your mouth as opposed to your nose? I’ve always thought that doing so bypasses all the nose hairs and other such defenses, such that you’re directly introducing dust, fungus spores, and what have you into your lungs, where they can infect/grow/whatever. Am I wrong? ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [November 21, 2009, 1:11am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/2 "2009-11-21T01:11:07Z")
I would greatly appreciate it if others breathed through their mouths, particularly those with nose whistles. Theoretically a habitual mouth-breather would take in more particulate matter than others, but I doubt this typically achieves clinical significance. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [November 21, 2009, 2:13am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/3 "2009-11-21T02:13:31Z")
if you breath though your mouth you could suck in a bug. i do agree that nose hairs and snot and turbulent passages would filter particulates that you would inhale deep into your lungs breathing through your mouth. maybe a much less of an issue is odor detection of bad air that wouldn’t happen through your mouth. ---
**Author:** ![Serenata67](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/serenata67/32/10646_2.png) [@Serenata67](https://boards.straightdope.com/u/Serenata67)\ **Post date:** [November 21, 2009, 3:07am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/4 "2009-11-21T03:07:25Z")
> [@johnpost](#): > > if you breath though your mouth you could suck in a bug. > > i do agree that nose hairs and snot and turbulent passages would filter particulates that you would inhale deep into your lungs breathing through your mouth. > > maybe a much less of an issue is odor detection of bad air that wouldn’t happen through your mouth. I don’t know about avoiding smell by mouth-breathing. There are some particularly… uh… frangrant customers who come in to my work. Most smell like awful rancid body odor, but some are old ladies doused in White Diamonds or whatever old lady reek they have on today. Anyway, I’ve learned that breathing through my mouth doesn’t keep me from smelling them. ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [November 21, 2009, 11:34am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/5 "2009-11-21T11:34:55Z")
if you mouth breath, you can dry out your mouth, and it can cause 'meth mouth, where the teeth are adversely affected by lack of saliva creating a great microbe breeding environment at the roots of the teeth. ---
**Author:** ![kapri](https://avatars.discourse-cdn.com/v4/letter/k/4491bb/32.png) [@kapri](https://boards.straightdope.com/u/kapri)\ **Post date:** [November 21, 2009, 3:45pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/6 "2009-11-21T15:45:05Z")
I can only breathe through my mouth when engaged in intense exercise such as running and spinning (deviated septum? I don’t know–my sinuses just close up after a few minutes of exercise), and I hate it. My mouth gets really dry, and it’s hard to find a decent breathing rhythm. Please there’s the whole “breathing in a bug” problem. That’s happened more than once. It is a better way to breathe, though, when running by a dead animal on the road, for obvious reasons. ---
**Author:** ![handsomeharry](https://avatars.discourse-cdn.com/v4/letter/h/e9c0ed/32.png) [@handsomeharry](https://boards.straightdope.com/u/handsomeharry)\ **Post date:** [November 21, 2009, 4:11pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/7 "2009-11-21T16:11:59Z")
I was reading some kind of mini-yoga article on breathing, and it mentioned that breathing throught the nose was helpful in that it heated the air a bit more. Don’t remember the significance, tho. hh ---
**Author:** ![Add99](https://avatars.discourse-cdn.com/v4/letter/a/977dab/32.png) [@Add99](https://boards.straightdope.com/u/Add99)\ **Post date:** [November 21, 2009, 5:25pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/8 "2009-11-21T17:25:26Z")
A martial arts sensei told me to inhale through the mouth, exhale through the nose, causing oxygen to be taken in quickly and held in the lungs longer, thereby avoiding exhaustion. ---
**Author:** ![Hero\_From\_Sector\_7G](https://avatars.discourse-cdn.com/v4/letter/h/65b543/32.png) [@Hero\_From\_Sector\_7G](https://boards.straightdope.com/u/Hero_From_Sector_7G)\ **Post date:** [November 21, 2009, 5:48pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/9 "2009-11-21T17:48:38Z")
> [@Add99](#): > > A martial arts sensei told me to inhale through the mouth, exhale through the nose, causing oxygen to be taken in quickly and held in the lungs longer, thereby avoiding exhaustion. Oxygen in the lungs is being transferred to the blood and _used_ as electron acceptors for cellular respiration. I don’t know the precise rates at which oxygen and CO2 are being transferred, but if I had to guess I would say it is roughly equivalent - your inward breath (for oxygen) should be about equivalent to your outward breath (to eliminate CO2). ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [November 21, 2009, 5:57pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/10 "2009-11-21T17:57:51Z")
I’ve wondered this, too, myself. I breathe mostly through my mouth, mainly due to the fact that as a kid I had a lot of sinus problems and, by habituation, I ended up learning to breathe through my mouth. These days, I’m still probably a majority mouth breather. I personally haven’t had any sort of health or dental issues attributed to it, and none of my doctors seemed particularly worried when I mention to them how I breathe. When I eat, I generally do switch to nose breathing reflexively, so I could better taste my food. And my experience with blocking out offensive smells is a little different than **Serenata** ’s. I miss many noxious odors when I’m in mouth-mode. For me, the main danger is this. Sometimes I’ll miss the smell of a gas burner left on, for example. On the plus side, no bathroom in the world has ever bothered me when I’m in mouth breathing mode. But I’ve also noticed that there are two ways I could breathe through my mouth, one which lets a tiny little bit of air in through the nose, and the other which completely blocks off the nostrils. ---
**Author:** ![Llama\_Llogophile](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@Llama\_Llogophile](https://boards.straightdope.com/u/Llama_Llogophile)\ **Post date:** [November 21, 2009, 8:58pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/11 "2009-11-21T20:58:15Z")
> [@handsomeharry](#): > > I was reading some kind of mini-yoga article on breathing, and it mentioned that breathing through the nose was helpful in that it heated the air a bit more. I was told the same thing in anatomy class back in the day. Being routed through the pharynx, the air is heated somewhat enroute to the lungs. Not sure why that’s an adaptive trait, however. ---
**Author:** ![Zsofia](https://avatars.discourse-cdn.com/v4/letter/z/7bcc69/32.png) [@Zsofia](https://boards.straightdope.com/u/Zsofia)\ **Post date:** [November 21, 2009, 9:01pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/12 "2009-11-21T21:01:49Z")
When I’m running in the cold and can’t get enough air through my nose (or it hurts because it’s so cold) the back of my throat ends up in an agony of cold because I’m breathing through my mouth. ---
**Author:** ![constanze](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@constanze](https://boards.straightdope.com/u/constanze)\ **Post date:** [November 21, 2009, 10:54pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/13 "2009-11-21T22:54:05Z")
> [@Mach Tuck](#): > > I was told the same thing in anatomy class back in the day. Being routed through the pharynx, the air is heated somewhat enroute to the lungs. Not sure why that’s an adaptive trait, however. IAMNAD, but the three functions of the nose for breathing I usually hear are given as: filtering out stuff through the hairs warming the air up to body temp. to prevent heat loss in the central body part making the air wet I assume the last two parts are to make things easier in the lungs - if the lungs itself have to cope with a large amount of dry and cold air, it’s not good for the body. ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [November 23, 2009, 3:00pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/14 "2009-11-23T15:00:18Z")
> [@handsomeharry](#): > > I was reading some kind of mini-yoga article on breathing, and it mentioned that breathing throught the nose was helpful in that it heated the air a bit more. Don’t remember the significance, tho. > > hh Cold air can irritate twitchy airways - a trigger for some asthmatics (including me). Nose breathing can mitigate that problem somewhat. I remember being utterly puzzled that anyone would use Afrin etc. to keep their nasal passages open, as my nose was never of much use when attempting to breathe. Then I had a dentist tell me that my mouth-breathing was causing gum irritation; an allergist suggested that I might well have polyps… I wound up having surgery for deviated septum (congenital) and to trim the turbinates (combination of congenital and I think the result of a lifetime of allergies) - no polyps that they ever told me about - and all of a sudden, I understood that people really DO breathe through their noses. I believe my asthma improved somewhat as well. Not just from the cold, but less in the way of allergens / particulates were making their way into my lungs. The downside of course was that I was commuting into Washington DC at the time, through some Metro stations which were occasionally frequented by the unwashed segment of society. Improved sense of smell was NOT advantageous there! ---
**Author:** ![Markxxx](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@Markxxx](https://boards.straightdope.com/u/Markxxx)\ **Post date:** [November 23, 2009, 4:10pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/15 "2009-11-23T16:10:14Z")
It also causes hyperventilation or if not causes at least contributes to it. Years ago when I suffered from panic attack, I would over breathe and that leads to hyperventilation which causes tingling and other such things that only make the panic worse I learned simply by closing my mouth or even cupping my hands over my mouth to rebreathe the air it stopped it. Also breathing through your mouth would make it more likely to inhale air making you burb more than you should. ---
**Author:** ![Hilarity\_N.Suze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hilarity_n.suze/32/6223_2.png) [@Hilarity\_N.Suze](https://boards.straightdope.com/u/Hilarity_N.Suze)\ **Post date:** [December 16, 2010, 6:16am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/16 "2010-12-16T06:16:18Z")
> [@Add99](#): > > A martial arts sensei told me to inhale through the mouth, exhale through the nose, causing oxygen to be taken in quickly and held in the lungs longer, thereby avoiding exhaustion. Oddly enough, in Pilates it’s just the opposite. ---
**Author:** ![Hilarity\_N.Suze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hilarity_n.suze/32/6223_2.png) [@Hilarity\_N.Suze](https://boards.straightdope.com/u/Hilarity_N.Suze)\ **Post date:** [December 16, 2010, 6:19am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/17 "2010-12-16T06:19:11Z")
> [@Leaper](#): > > …I’ve always wondered: what harm, if any, is there in breathing through your mouth as opposed to your nose? It can screw up your teeth–both cavities and alignment. It’s a symptom of sinus problems as well as teeth problems (my understanding is, it can both result from and cause dental issues). ---
**Author:** ![tmoh](https://avatars.discourse-cdn.com/v4/letter/t/e5b9ba/32.png) [@tmoh](https://boards.straightdope.com/u/tmoh)\ **Post date:** [December 16, 2010, 7:13am UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/18 "2010-12-16T07:13:05Z")
According to my orthodontist, mouth-breathing makes you more likely to have an upper palate/jaw that’s too small to contain all your teeth in the right alignment. When you breathe through your nose, your tongue presses against the roof of your mouth, and apparently enough years of that works to spread out your palate so there’s space enough for everything; if you don’t, then your mouth ends up too small for your teeth and they have to grow in crooked, causing mouthbreathers like me to need many, many years of Very Serious Braces in order to avoid a lifetime of interdental food-trappage. Not having studied anything about teeth myself, I have no idea if he was right. ---
**Author:** ![Anaamika](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@Anaamika](https://boards.straightdope.com/u/Anaamika)\ **Post date:** [December 16, 2010, 2:24pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/19 "2010-12-16T14:24:11Z")
Mouth breathing makes your lips dry out really fast, doesn’t it? Licking them doesn’t seem to help. ---
**Author:** ![Antigen](https://avatars.discourse-cdn.com/v4/letter/a/848f3c/32.png) [@Antigen](https://boards.straightdope.com/u/Antigen)\ **Post date:** [December 16, 2010, 2:38pm UTC](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359/20 "2010-12-16T14:38:10Z")
> [@tmoh](#): > > According to my orthodontist, mouth-breathing makes you more likely to have an upper palate/jaw that’s too small to contain all your teeth in the right alignment. When you breathe through your nose, your tongue presses against the roof of your mouth, and apparently enough years of that works to spread out your palate so there’s space enough for everything; if you don’t, then your mouth ends up too small for your teeth and they have to grow in crooked, causing mouthbreathers like me to need many, many years of Very Serious Braces in order to avoid a lifetime of interdental food-trappage. > > Not having studied anything about teeth myself, I have no idea if he was right. I was told the same thing by my orthodontist. Well, he didn’t mention the tongue thing, but he said breathing through the mouth causes the upper palate to deform somehow and that’s why my teeth were all over the place. [Next page](https://boards.straightdope.com/t/whats-the-harm-if-any-in-breathing-through-ones-mouth/518359.md?page=2)