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Curious Kids: I heard that breathing through your mouth makes your IQ go down. Is that true?

What’s better – breathing through your nose or your mouth? Flickr/Lauren Rushing, CC BY

Curious Kids: I heard that breathing through your mouth makes your IQ go down. Is that true?

This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!


Hello. My name is Mannix and I am 10 years old. I want to know if it is better for your brain and body to breathe out of our nose than your mouth? I worry about this as I saw on YouTube that your IQ was less if you breathed through your mouth but how can I do this if I have a cold? My mum says I should not worry. – Mannix, aged 10, Sydney

Hi Mannix. Your mum is right; you shouldn’t worry. The way you breathe has no effect on your IQ.

However, breathing in through your nose has a number of benefits.

Firstly, it helps to warm and add moisture to dry air to make it less irritating to our lungs and trachea, which is the scientific word for your windpipe.


Read more: Curious Kids: Are zombies real?


The nose has a number of bony ridges, called turbinates, which increase its surface area and scatter the air flow.

The nose has special features that help filter out dust and dirt. Flickr/Shelby H., CC BY

Unfortunately, the downside is when the skin over these ridges swells from colds or allergies they narrow the air passage and makes breathing through your mouth easier than via your nose.

Secondly, the microscopic hairs in your nose help to trap dust and other foreign particles, removing most of them before they get sucked into your lungs.

Fortunately, most of us live in relatively climate-controlled environments with fairly good air quality. This means we can do fine without the additional benefits that nose breathing provides over mouth breathing.

Evidence-based medicine

That’s a great question, though. It can be hard to find good information on the internet about health. There are many ways information on the internet can confuse us. It’s important to be careful about not trusting everything we read.

There is something called bias, which might cause us to believe something that’s not completely true. “Confirmation bias”, for instance, happens when you already have an opinion about something and then look for ways to confirm your opinion and ignore all the other information that suggests your opinion might be wrong.


Read more: Evidence-based medicine


The practise of using good information for health is called “evidence-based medicine”. This might be something you want to look up on the internet.

Noses are good for smelling as well as breathing. Flickr/Derek Hatfield, CC BY

Some good sites for health information include this website by The Royal Children’s Hospital which has a bunch of stories about different health conditions. The KidsHealth website also has some awesome videos about how the body works. The CSIRO is an Australian science institute who discovered a heap of great stuff like wi-fi. They have some videos on science and health you can find here.

Your curiosity in science and health is great. Keep asking questions, and good luck with your future endeavours!


Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. They can:

* Email your question to curiouskids@theconversation.edu.au
* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or
* Tell us on Facebook

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Please tell us your name, age, and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.