Unless it’s absolutely necessary – like Tabata intervals necessary, we should refrain from breathing through our mouths.  Nasal breathing, as opposed to oral breathing, confers several health and performance benefits that until very recently, have been largely neglected in the scientific literature.  Below I’ve compiled what I believe to be the three main health and performance advantages of breathing in and out through the nose…


  • Improved immune system function.


Spending prolonged periods of time in a sympathetic (i.e. fight or flight) state can weaken the body’s immune system.  Subjecting the respiratory system to unwanted germs can also weaken immunity. Breathing exclusively through the nose addresses both of these problems.  Firstly, nasal breathing improves vagal tone which helps tilt the body towards a more parasympathetic (i.e. rest and digest) state so that the immune system can function at its best.  Secondly, filtration of air through the sinuses can greatly aid in fighting off upper respiratory tract infections. In short, nasal breathing promotes optimal immune function by reducing chronic stress and filtering unwanted particulates from the air.


  • Improved breathing mechanics.


The ability to breathe well is crucial for health.  Whether it be for stress control, for maintaining proper joint function, or for promoting metabolic health, breathing mechanics are fundamental for feeling good.  By breathing through the nose, the diaphragm is forced to work properly and pull the lungs open from the lower abdomen rather than through the chest. The advantage of (primarily) belly breathing versus chest breathing is threefold: improved vagal tone for stress reduction, increased intra-abdominal and intra-pleural pressure upon inhalation which may improve joint health, and increased gas exchange efficiency in the lower lobes of the lungs.  In layman’s terms, by breathing through your nose, you’ll feel less anxious, your back will hurt less, and your energy levels will be more consistent throughout the day.


  • Performance benefits.


First, a quick physiology lesson…  At any given time, the body runs on a spectrum of aerobic and/or anaerobic metabolism.  The aerobic system is virtually limitless and can produce energy indefinitely.  The anaerobic system is limited and can only function (albeit at a very high output) for a short period of time.  During low-intensity activity like walking or jogging, the body primarily utilizes the aerobic system; this is why for example, an ultra-marathoner can run for hours and hours at a time.  During high-intensity activity like sprinting, the body primarily utilizes the anaerobic system; this is why an ultra-marathoner would never be able to sprint through the entire race.  

So now that we understand basic bioenergetics, we can come back to discussing the importance of nasal breathing for performance…  By manipulating the way we breathe (e.g. only through the nose) during training, we can specifically raise our maximal aerobic power, which is the ability to perform the highest output of work while still staying within the aerobic energy system.  Maximal aerobic power, or the ability to work at a high pace indefinitely, is hugely important to any sport or activity that requires cardiorespiratory fitness.  While this may be an oversimplification, whoever works the hardest, for the longest period of time will generally do well in their chosen sport or activity. 

A second physiology lesson… lactate threshold is the point in which aerobic metabolism begins to switch over to anaerobic metabolism.  At lactate threshold, carbon dioxide (which is a by-product of anaerobic metabolism) production begins to rise disproportionately to oxygen consumption and breathing rate increases in order for the body to blow off the excess carbon dioxide.  Because the mouth is much wider than the nostrils, blowing off excess carbon dioxide is best done through the mouth. Now based off of that information, if lactate threshold signals the turning point from a limitless (i.e. aerobic) to a limited (i.e. anaerobic) energy system, and the goal of the competition is to go as hard as possible for as long as possible, then we know that having to breathe through the mouth is a sign that we need to dial the intensity of activity back in order to maintain a sustainable pace!  In this way, nasal breathing during training is an excellent way for athletes to learn better pacing awareness – having them rev their aerobic system as high as possible without tipping over into the anaerobic system. Finally, and this is an analogy used by world-renowned performance coach Brian Mackenzie: nasal breathing adds “gears” to our cardiorespiratory performance. Right before the point in which we are forced to start breathing in and out through the mouth, we are functioning at a very high power output mainly through the aerobic energy system.  Once mouth breathing begins, we still in theory have a TON of capacity to perform work through the aerobic energy system in addition to the anaerobic energy system.  So get off your old Wal-Mart 3-gear bike, and build yourself a shiny new 21-speed beast with more nasal breathing!  In part 2 of this series, we will discuss specific nasal breathing drills and exercises that can be used to increase both health and performance.

As always, if you’d like to know more about, and start taking responsibility for your own health, fitness, and wellness, please reach out to Crux Fitness Richmond for any of your personal training needs.

Patrick Koo – Personal Trainer at Crux Fitness Richmond



Walker, A., Surda, P., Rossiter, M., & Little, S. (2016). Nasal function and dysfunction in exercise. The Journal of Laryngology & Otology, 130(5), 431-434.

Zaccaro, A., Piarulli, A., Laurino, M., Garbella, E., Menicucci, D., & Neri, B. (2018). How breath-control can change your life: A systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience, 12, 1-16.

LaComb, C.O., Tandy, R.D., Lee, S.P., Young, J.C., & Navalta, J.W. (2017). Oral versus nasal breathing during moderate to high intensity submaximal aerobic exercise training. International Journal of Kinesiology & Sport Science, 5(1), 9-16.

Pallarés, J.,G., Morán-Navarro, R., Ortega, J. F., Fernández-Elías, V. E., & Mora-Rodriguez, R. (2016). Validity and reliability of ventilatory and blood lactate thresholds in well-trained cyclists. PLoS One, 11(9) 

Kromenacker, B.W., Sanova, A.A., Marcus, F. I., Allen, J.B., & Lane, R.D. (2018). Vagal mediation of low-frequency heart rate variability during slow yogic breathing. Psychosomatic Medicine, 80(6), 581-587.


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