Nasal Airway in Regulation of Airway Resistance During Hypercapnia and Exercise

By Mark Roberts | Sun Feb 03 2019

Study reviewed by XPT Assistant Performance Director, Mark Roberts

Nasal breathing during exercise has been a topic of consideration for both trainers and trainees for many years. Research in this area has helped athletes answer the question, “is it better to breathe through your nose or mouth when exercising?”

In this study, researchers look at the relationship between nasal resistance and A) hypercapnia (a higher presence of CO2 in the body) and B) exercise. The researchers took 10 healthy volunteers and used posterior mask rhinomanometry to measure nasal resistance in the following tests:

·      Exercise: Volunteers peddled on a stationary bike at three varied loads. 

·      Hypercapnia: This was measured by supplying three different O2/CO2 mixtures: 5% CO2, 6% CO2, and 8% CO2. 

Resistance was measured during the expiratory breath only. This was because of the potential for nasal collapse/flare during inspiration.

The results show a linear decrease in nasal airway resistance as both exercise and CO2 levels increase. What this means is that respiratory efficiency increases as the demand increases while decreasing the amount of work the overall respiratory system has to do at high ventilation rates.

What Can We Take Away?

So, based on the study, should you breathe through your nose during exercise? The major takeaways from the study suggest so.

  • The best way you can add resistance to the respiratory system is through




    Adding a small amount of resistance to the breath increased work rate by 50 percent, ultimately increasing tidal volume, increasing inspiratory duration, and decreasing respiratory frequency.

  • If you spend most of your time nasal breathing, you can regulate your



    (breathing to match metabolic demand) so you are not over breathing. This is important for maintaining higher levels of CO



    in the blood to become more efficient at dropping oxygen off to cells and tissues. Not only that, but you can also regulate stimulation of the parasympathetic nerve.

  • If you stay patient and work on becoming a competent nose breather, your athletic capacity can be improved greatly. Just imagine being in a position where increased cardiopulmonary output can be made more efficient and less energy consuming, leaving you with an overdrive gear when others are maxed out.

Hopefully this study breakdown helps you answer the question, “How should I breathe when working out?” To learn more, read the original study here.

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