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Are You Breathing Too Much?

"Take deep breaths. In through your nose, out through your mouth...". No, don't, please stop!

Your mouth shouldn't be used for breathing unless absolutely necessary (i.e. intense exercise or illness preventing use of your nose!). Your mouth is for eating and communicating (among other things - behave yourself).


Breathing through your mouth lets you take in a larger volume of air and lets your dump out a larger volume of carbon dioxide (CO2).


Nose breathing helps you breathe less (your nose is smaller than your mouth!), which believe it or not is a good thing. Your blood is saturated with oxygen (96-98%) at all times; more breathing does not mean more oxygen saturation. Increase breathing does mean more CO2 expulsion which results in lower levels of blood CO2. CO2 is waste, right? It's bad, get rid? Wrong!


Having CO2 in the blood is vital for oxygen exchange (blood to muscle cell) - the more CO2 present, the more oxygen can be supplied to the muscle in need.


Your brain controls your breathing - you know that feeling when you're holding your breath and you just HAVE to breathe? That's your brain monitoring blood CO2 and deciding when to send a "breathe more" message to the relevant muscles. It does this because it has a pre-set tolerance level for blood CO2 - when you exceed this level it wants you to breath air IN so you can breath OUT some of that CO2.


Luckily, this tolerance can be worked on and improved. If you can tolerate a higher blood CO2 level, your oxygen exchange will become more efficient and you will be fitter as a result.


How do we improve our tolerance to CO2, then?


  1. Try to nose breathe all day and all night*. Try to keep your breathing light. Depending on what your breathing is currently like this may take some practice - try to stay aware of how your breathing and to catch yourself out when you start using your mouth!

  2. Introduce nose breathing to light exercise - keep the intensity at just below the level where you have to mouth breathe.

  3. Introduce breath holding exercises.

Quick note; if you have a pre-existing condition exercise caution with breath holding exercises - it's worth doing some research or talking to your doctor first!


Measure your progress with BOLT: Blood Oxygen Level Test.


  1. At complete rest, take a normal breath in from your nose and a normal breath out though your nose.

  2. Hold your nose to prevent a breath in.

  3. Time how long in seconds until you feel the desire to breathe; you might experience the urge to swallow, airway constriction or contraction of breathing muscles in abdomen/chest/throat.

  4. Release your nose, stop the timer and breath calmly through your nose.

  5. Resume normal breathing.


Be honest with your score - it's not a breath holding competition, it's a test! You shouldn't be purple in the face and gasping for air at the end.


Most trained individuals will score around 20 seconds. Your long term goal, to reach your full potential, should be 40 seconds. A normal or elite BOLT score shows a higher tolerance to CO2 - with a high score you'll be more able to maintain calm breathing during rest and experience less breathlessness during exercise.


Anything less than 20 should really be addressed. Lower scores indicate your CO2 tolerance is particularly low. At 10 seconds your breathing is likely dysfunctional; noisy, irregular, heavy, rapid, you likely mouth breathe and you'll frequently experience a "hunger" for air during rest or very light movement (walking, climbing stairs etc.).


Any questions fire them to my inbox - details on the contact page!


Happy breathing.

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