A thread on Nasal Breathing - Why it it is necessary for human function & performance

Travis et. al, 1996 found that breathing through the nose during aerobic exercise decreased perception of stress/intensity and significantly endurance...

This is because it improves the efficiency of oxygen delivery.

The Bohr Effect describes how Carbon Dioxide (what we breathe out) leads to oxygen released by storage hemeproteins in our blood to our tissues.

When CO2 , we are triggered to breathe more air in.

However, if we breathe too much air in (overbreathing) through the mouth, we will exhale too much CO2.

This can cause us to offload too much and then the concentration of CO2, therefore the delivery of oxygen to our tissues and muscles.

This then the rate of the breath and then fatigue.

If we nasal breathe, we:

- Clean the air as it enters
- Use our diaphragm more and less risk for compensatory neck breathing
- Produce Nitric Oxide which controls bloodflow and oxygen uptake in cells/working tissues

Dallan et. al, 2018 compared endurance runners utilizing nasal only vs mouth only breathing.

They found maximum rate of oxygen consumption was not different, but the ratio of oxygen intake to CO2 output during nasal breathing which was due to efficiency of oxygen delivery.

However, at some point during highly intense exercise, we will need to start breathing through our mouth.

Recinto et. al, found that during anaerobic power training (high intensity output on a cycle), it didn’t matter as much. Using a combination of both nasal and mouth

breathing is probably ideal.

As for outside of exercise, it is still massively important.

The term “mouth breather” has a negative connotation to it for good reason.

In terms of human development, mouth breathing patterns have been shown to facial/cranial development.

The jaws do not fully develop and are set back from their ideal position, thus reducing airway size. If the jaws are not positioned forward enough on the face, they will encroach on the airways (McKeown, 2015).

If we sleep with our mouth open, this can also promote overbreathing