There is a large misconception that we get the urge to breathe because we aren’t taking in enough oxygen but this is absolutely false. In fact it is common for people to over-breathe (we call this hyperventilation).
We get our urge to breathe because our bodies have a build-up of carbon dioxide (CO2). It has often been thought that CO2 is a waste gas, kind of like urine. But again this is false, it is an essential gas for human bodies. Not only is it the body’s primary stimulus to breathe but it is also responsible for stimulating your haemoglobin (the part of blood that carries oxygen) to deliver the oxygen to your muscles.
Think of it like this - your haemoglobin is the bus and it carries the passengers, oxygen, to your muscles. When it gets to your muscles the conductor says “show me your ticket.” The ticket is CO2. If the muscle hasn’t worked hard enough and doesn’t have enough CO2, the haemoglobin will hold onto the oxygen and not deliver it to the muscle.
Breathing correctly is not a new concept, I have often heard it referred to as the forgotten art. In 1904, Christian Bohr, a Danish biochemist discovered that “the lower the partial pressure of carbon dioxide in the blood the greater the affinity of haemoglobin for the oxygen it carries”. To put it simply the lower the pressure of CO2 in the blood, the less oxygen is released by the haemoglobin into the cells for the production of energy. Conversely, an increase of CO2 in the blood, due to the drop in blood PH, causes the haemoglobin to release their oxygen load. This process was named the Bohr effect.
To tie the above concepts together:
· As you exercise you increase your levels of CO2 in the blood. Your lungs can’t get rid of CO2 fast enough and so your brain receives the stimulus to breathe faster (think of your very first memory of running fast, red faced and breathless).
· As you start to breathe faster more air travels through your lungs than you can absorb. This then starts to blow off (get rid of) the CO2, which then has the negative effect described above.
· Not only does breathing harder blow off CO2 but the act of breathing (especially hard and fast) adds work load to your body, creating the need for more oxygen and increasing CO2 further.
· The lower your tolerance to CO2 the earlier in exercise you need to increase your breathing rate. This then makes it more likely that you will blow off your CO2, resulting in less delivery of oxygen to the muscles. Which then results in an inability to produce energy, and an increase in muscle fatigue.
The good news is we can use this response to great effect.
Our goal then is to train our bodies to tolerate CO2. This means you can maintain a more efficient breath for longer as your CO2 levels increase.
You also get the added benefit of more efficient delivery of oxygen to your muscles, which in turn delays the onset of lactic acid and fatigue. You will also waste less energy on poor breathing technique (see article to come on good breathing technique) and waste less energy on the overuse of supporting breathing muscles.
With the right training and instruction we can use this mechanism and breathing techniques to enhance your training.
Spending more time being exposed to higher levels of CO2 can not only allow you become more tolerant to CO2 (delaying the onset of heavy breathing) but also delay fatigue. Fatigue is not just a feeling, it is a physiological occurrence where the body reaches a breaking point at which it cannot continue to exercise at that intensity. This results in the athlete having to slow down their intensity or cease performance altogether.
Continued exposure to higher levels of CO2 during training forces the body to make adaptations, thereby delaying the onset of fatigue. Which of course then increases your performance.
It’s amazing how long it is still taking for this science to enter the mainstream narrative. It is still far from widely understood and embraced in the running world. Athletes who are willing engage with the science and learn specialised breathing techniques will be have a secret weapon in their toolbox when it comes to enhanced performance.