Breathing is a consistent topic of conversation in martial arts. Several good reasons for nose breathing have already been put forth, I will list them below as well as a few that I am aware of.
- The nose is a natural filter which filters out dust and other particles to prevent bronchial and other infections.
- Breathing through the nose and hence sinuses better warms the air which assists in preventing cramping in cooler weather.
- Breathing through the nose also slows the breathing which tends to result in deeper breaths than the short gasping breaths we are prone to when mouth breathing. Deeper breathing better oxygenates the blood because we fill the lungs to greater capacity this means you actually need less breaths to get the same amount of oxygen in the blood.
- Breathing in through the mouth relaxes the jaw which can result in loose mouthguards, broken jaws and knockouts. If you think you can breathe in through your mouth without unclenching the teeth give it a try, the airflow is similar to the nose and you tend to just get a lot of saliva and lip flapping.
So now if we work under the above assumptions for why we inhale through the nose lets see why we want to exhale through the mouth.
- Rapid expulsion of breath is important for absorbing strikes when we are hit and generation of force when we hit.
- Clearing the carbon dioxide from our body is paramount during vigourous activity to make room for more air, so we get rid of it via the quickest mechanism.
- Breathing out through the mouth has no impact on the depth of breathing as if we have already inhaled through the nose properly exhaling will occur from the entire lung.
- If we breathe out through our nose the sinus cavity will retain a portion of that exhaust breath which we would otherwise have expelled through our mouth so cycling the breath results in reduced CO2 intake which each subsequent breath.
So cycling the breathing in through the nose and out through the mouth provides the best combination between the benefits of nose breathing and the rapidity of mouth breathing.
A corallory to this is Yoga breathing. I was recently discussing this with my instructor as she teaches to breathe in and out through the nose while I am teaching my students to cycle their breath.
She pointed me to this website, YogaToHealth
, I had expected this to give me contradictory information to what traditional martial arts teaches. Surprisingly their reasons for exhaling through the nose are the same as our reasons for exhaling through the mouth. Firstly nose breathing forces you to control your breath which is vital in Yoga training. Secondly they use nose breathing to ensure that the balance of CO2 in the blood is maintained which makes sense given the low intensity nature of their workout while martial arts being higher intensity requires us to expel a lot more CO2. The reasoning behind this is clear if you understand how your body regulates breath. Our body has no sense of how much oxygen is in our blood. Breath is regulated based on the levels of CO2. This is why deep sea free divers who intentionally hyperventilate prior to a dive have been known to just pass out and drown. They have very little CO2 in their blood and hence do not feel the urge to breathe and go farther than they are actually able.
So while in Yoga they use pure nose breathing to regulate breath and we use cycled in through the nose and out through the mouth breath for the same reasons there is little reason to breathe entirely through the mouth except when your diminished lung capacity due to injury, exhaustion, disability such as asthma demands it of you, definitely not something you want to train. That is unless you are not overly attached to your teeth or the feeling of being conscious.
My instructor used to say that there is a reason we say we need to catch our breath. It's because it's gotten away from us and we are no longer in control. Martial arts is all about control.