I like to start with basics, ala John Wooden, as they are so often the platform upon which later success is built. The most basic part of endurance sport is breathing , although the concept is almost never addressed as a learned skill. Most athletes, coaches and scientists default to the position that breathing simply occurs, so however it occurs must be best. During exercise this most often means opening your mouth and breathing as deeply and quickly as needed. I felt this way myself for approximately the first 40 years or so of my currently 54 year athletic career – swimming, water polo, cycling, running, triathlon and a little wrestling thrown in for good measure (I grew up in PA where wrestling is religion ;-). The thing that finally changed my thinking on this was getting sick – literally all of my athletic life. Colds, bronchitis, pneumonia – later sinus infections and exercise induced bronchoconstriction (EIB), starting from my early age group swimming days and continuing until about 14 years ago. Finally, one weekend, sitting around with a sinus infection, feeling like crap and unable to train – I decided to step out of the box. Stepping out of the box meant looking elsewhere for help – in this case the internet – as the train of health care practitioners I’d seen over my life had not helped this problem in the least. Weirdly, I came across two ideas: breathing through your nose while running and using a Neti Pot everyday. So I started doing both. Initially I could barely complete the early and slowest stages of my running warm-up before the urge to breathe (what is called it air hunger in the scientific literature) would force me to open my mouth. However, relatively, quickly I began to notice I could go further before this air hunger appeared. In cycling it was easier and very quickly I could do all of my training this way by simply going a little easier than normal. Over the next 6 months or so I found I was able to build up to doing all of my normal training, at all intensities, breathing nasally, without the sensation of air hunger occurring, while breathing only through my nose (both in and out). Approximately a year after starting this wackadoodle approach I did a corporate cup mile race and bicycle time trial I had been doing yearly for about a decade in faster times than I had ever done before – no mean feat in an aging athlete in his late forties. Beyond this, I went for a period of about 5 years without once getting sick – no colds, bronchitis or pneumonia, sinus infections, no nothing.

Of course this was all anecdotal, so as a scientist/coach I knew it was time to start studying the phenomenon in other people. None of the elite athletes I was working with at the time were willing to give it a solid go. Amanda Stevens, bless her heart, gave it a try one day on a run and then gave me that pitying look young physicians reserve for the very stupid when I asked her about it later. Hunter Kemper never even entertained the possibility, apparently chocking the idea up to idiosyncratic behavior you just accept in someone who has otherwise been helpful to you. However, others, who held me in a higher (although less realistic) levels of esteem just assumed I knew what I was talking about and gave it a serious try – experiencing a similar process to what I had gone through.

Eventually, there was a small cadre of people who had “adapted” to nasal only breathing during exercise and so we began to study the concept formally. We initiated this process as pilot work later published as a case study found here: https://journals.tdl.org/jhp/index.php/JHP/article/view/70

Later, I was able to resource my small group of dedicated nasal breathers, as well as some others I came across, to complete this group study: http://journals.aiac.org.au/index.php/IJKSS/article/view/4400

The basic take away from these two studies is as follows. Not only is it possible to adapt to breathing exclusively nasally while running, without loss in performance, but performance may also be improved as a result of better physiological economy.

The improved running economy we have seen with nasally restricted breathing probably results from the now established observation that nasal breathing provides the required oxygen needed by the working muscles without requiring as much ventilation – actually about 23% less on average – at high levels of work. This idea is referred to as ventilatory efficiency. Ventilation is also a muscular activity and makes up about 15% of the total energy requirement needed to run fast – like at race pace for a 5K. Consequently, if you improve ventilatory efficiency in this way, you then reduce the need for energy and oxygenation and can then theoretically run about 1-3 percent faster as a result. This might turn a 6:00 mile pace for 10 K into a 5:50 pace for instance, just by breathing differently.

The adaptive process requires some extended period of time from about 1- 3 months, whereby you start training breathing nasally only at intensities where you do not feel significant air hunger, and then gradually increase training intensity as air hunger disappears. If you eventually include a full spectrum of intensity in your training, ranging up to aerobic capacity (VO2max) level work ( basically 800 meter to 1600 meter running performance speed in most athletes, depending on ability), then you will eventually be able to run at any pace breathing nasally, including during racing.   In addition, using a nasal splinting device or internal nasal dilator can help you achieve higher exercise intensities in this condition as you adapt.   Later these can be used to boost key training sessions and racing.

The additional benefit of breathing nasally in training and competition is likely be a lower probability of sickness and the prevention or elimination of exercise induced bronchoconstriction (EIB)  . The reduced EIB  outcome has been previously established in those who already have asthma and experience bronchoconstriction during exercise as illustrated here: https://www.atsjournals.org/doi/abs/10.1164/arrd.1978.118.1.65 

In the triathlete case study discussed previously , the subject retained a bonchoconstricitve response while breathing orally which disappeared while breathing nasally.  Anecdotally, I can add that I ‘ve seen several athletes with moderate to severe EIB overcome it by adapting to nasally restricted breathing, including myself.

Finally, there may be range of other exercise related benefits from breathing nasally which are yet to be established including reduced water loss (nasal breathing reduces expired water in comparison to oral breathing at rest), increased parasympathetic regulation (nasal breathing creates greater parasympathetic response at rest)) , reduced tooth decay (nasal breathing retains moisture in the mouth) and a reduced potential for myocardial ischemia (orally dominated hyperventilation induces coronary artery constriction at rest).

There are some minor downsides to breathing exclusively through your nose while exercising.  Initially nasal breathing during exercise produces lots of mucous and efflux meaning you will need to blow your nose more frequently for some time. However, in my experience (14 years nasal breathing during training and racing), this response also diminishes greatly over time.  In addition, I occasionally still get sinus headaches – typically following a rapid change in temperature from hot to cold in the very low humidity conditions where I live combined with a long day on the bike. This might be attributable to simple dehydration , but it may also be exacerbated by the increased need for humidification in the nasal cavity when breathing nasally.   Of course the parallel response when breathing orally is significant post exercise coughing and probable tissue damage in the lung.  

If you decide to try this be patient – it takes some time to adapt – however, in my experience it has been worthwhile.