• Question: why do you yawn when you are tired???????

    Asked by xograciexo to Daniela, Hannah, Ian, Jono, Mark on 24 Jun 2013. This question was also asked by 10johmadw.
    • Photo: Ian Wilson

      Ian Wilson answered on 24 Jun 2013:


      Hi xograciexo,

      Honestly, nobody quite knows yet! I suppose the problem is that we don’t just yawn when we’re tired. We also do it when we’re bored or when we see someone else yawn. We even do it when we’re thinking about it – I honestly just yawned typing the last sentence!! There are plenty of theories though and one of them sounds like a very sensible explanation for yawning when tired.

      A study proved that yawning increases the flow of blood to the brain. The brain needs oxygen to work efficiently and blood contains oxygen when it leaves the lungs. So the more blood the brain gets, the more oxygen it gets. One of the regions of the brain that benefits most from this is responsible for controlling consciousness, coordination and memory. So it could be that yawning is our body’s way of trying to wake up the brain and get us moving. That definitely explains why we yawn when we wake up.

      But it might be part of something a bit bigger. You’ve heard of the ‘fight or flight’ response, where our body prepares itself to respond to danger? Well it’s been proven that people yawn more just before stressful events like exams. So it might be that yawning bathes our brain in more oxygen so it can make us more alert to deal with dangers or stresses.

      Hope that helps,

      Ian

    • Photo: Daniela Plana

      Daniela Plana answered on 24 Jun 2013:


      Hi xograciexo!

      That’s a really good question and the answer is we are not 100% sure… there have lots of studies about yawning and different ideas have been suggested. For example, some people think that it is a way to quickly get oxygen into your body and particularly into your brain, which helps you stay awake. Other people think it is caused when your body is trying to keep alert and is related to several chemicals in your brain… other ideas have to do with it helping regulate your bodies temperature and relax you face muscles…

      So many different ideas! What we do know is that humans are not the only ones who yawn, most other animals with a backbone/spinal cord also yawn… and we don’t only do it when we are tired, but also sometimes when we are hungry, angry or stressed! However, humans are a bit funny because to us yawning is contagious… when we see other people yawn, we tend to do it! It’s been shown that has to do with our “empathy” or our ability to relate to how other people are feeling.

      Not sure I answered your question, but hope that helped a bit!
      Daniela

    • Photo: Mark Hodson

      Mark Hodson answered on 24 Jun 2013:


      hi xograciexo,

      I’ve always assumed it was to get more oxygen into our blood by increasing the amount of air we inhale. from what Ian and Daniela write it sounds like that could be the case.

      It’s one of the joys of science that there is still so much that we don’t know about things we can sometimes take forgranted, even something as simply as yawning.

      cheers

      m

    • Photo: Jono Bone

      Jono Bone answered on 24 Jun 2013:


      Hey Gracie,

      Well as others have said, it’s not because your tired.

      When you’re inactive (like sitting in a lesson) your body does not have much opportunity to expel excess carbon dioxide. Excess carbon dioxide in the bloodstream is dangerous, so your body responds by yawning and expelling more carbon dioxide that you would normally do by breathing.
      When exercising, you breathe heavily, so it’s easy to expel excess carbon dioxide. So its only an issue when you’re resting, whether this is because you’re tired or because you’re bored and sitting still.

    • Photo: Hannah Brotherton

      Hannah Brotherton answered on 25 Jun 2013:


      Hi xograciexo,
      I have asked everyone this question!!! I have even looked at my cats when they yawn to figure it out, but then I end up yawning myself. sooooo it is definitely addictive.

      People think (in the world of psychology) that is a social thing. We yawn to social, to bond with each other. This is why yawning is addictive. (its an evolutionary thing!) Sometimes we yawn when we are not even tired, which means it could definitely be a social thing and not just a biological thing.

      Scientists have noticed that when soldiers jump out of the planes in their parachutes they all yawn – well I hope its not because they are tired, because that would be dangerous……it supports this theory that it is a group social thing. In fact they think yawning is designed to keep us awake. So these soldiers yawn to each other to keep each other awake and aware of anything happening.

      So next time you yawn before an exam or before seeing a show – its not because your tired, you body is just making you sure you are wide awake and alert so you can work to the best of your abilities – so actually yawning before an exam is really good 😛

      Also, yawning is actually involved with our ears 😀
      When we yawn we are stretching our eardrums lol. so maybe it is like a little exercise for our eardrums to wake up and stay subtle so we can pick up sound vibrations and hear sound waves.

      Either way – yawning is still really addictive and tbh I’m writing this now and I’m yawning. Just saying the word is making me yawn…….its my brain making me alert to answer this question the best 😛

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