Should You Breath Through Your Nose, Mouth, or Both While Running and Exercising?
Anybody who is interested in barefoot running or has read the book Born to Run is probably familiar with the lore surrounding the running exploits of Native Americans.
In the book, Indian Running, author Peter Nabokov describes a Native American running exercise that taught runners how to strengthen their breathing. Taking in a mouthful of water (without swallowing), runners would sprint for set distances while holding the water in their mouths.
There are plenty of anecdotes like this of ancient runners traversing the land while breathing through their nose, and images of the Tarahumara Indians running across the Copper Canyons with their mouths closed and a peaceful look on their face.
Stories like these cause many of us to wonder, should I be breathing through my nose while running or exercising? Am I doing something wrong when I gasp for air through my open mouth?
This particular question is never more prominent in my mind than when I'm breathing hard at the end of a hard run or really intense workout. Sometimes I try to soldier through my training while breathing through my nose, but I always end up switching to orinasal, or breathing with both the nose and mouth. That painful feeling of not getting enough air is just too strong, and my instincts take over.
I've thought that perhaps I'm just weak mentally, or maybe my seasonal allergies have made my nose useless. The truth is actually more a mix of simple human physiology, neolithic anatomical maladaptiveness, and my own personal training preferences.
The Human Nose
Anybody wishing to learn more about the evolution of humans and the anatomical changes that made us who we are should follow the research of Dr. Dan Lieberman. Specifically, his book The Evolution of the Human Head is a wealth of information regarding the physiological changes that occurred to the human body throughout its million year evolution.
The chapter pertaining to the structure of the nose, and how it differs from the noses of other mammals and even other primates is particularly enlightening.
... the evolution of a turbulence-generating external nose in Homo suggests that the benefits of increasing turbulence must have outweighed the costs. A reasonable hypothesis is that selection acted on nasal shape to favor efficient function of the respiratory epithelium to humify inspired air and to dehumidify expired air during aerobic exercise.
Big, external noses may have helped our ancestors travel long distances in the hot midday sun - but only up to a point, because at some threshold the costs of high resistance would outweight the benefits of turbulent airflow. Because airway resistance is much lower in laminar than in turblent flow, increased resistance can become a problem duirng vigorous exercise, which increases the need for air.
So here we have one piece of the puzzle. The nose is engineered to keep us from drying out, an adaption that proved helpful in allowing humans to spread out from the jungles and across the savanna. It's one of the many features that allow us to run for long periods even in extreme ambient heat, but with a catch. Intense anaerobic activity requires more oxygen than can be pulled through the nose, due to increased turbulence and resistance.
Dietary Effects on Facial Structure
I've always recognized that my face and its features were a little on the narrow side. When I was a young boy and travelling with family on trips to the Florida Keys to explore coral reefs, I always had trouble fitting a snorkeling mask to my face. Its narrow shape always left pockets on the side where water got in.
Later in life, it seemed that allergies would become a perennial problem, with my nose becoming useless for several months out of the year. More outwardly apparent though, the poor structure of my teeth resulting from a palate too narrow for all of them to fit, was the final clue which lead me to understand my issues.
Around 70 years ago Weston A. Price had already figured out what my problem was. While studying indigenous populations of people all over the planet, and discovering how modern diets had affected them, he determined that non-traditional foods caused the children of these people to develop narrow facial structures. This phenotype consisted of crowded teeth, poorly developed jaws, and much diminished nasal cavities and nostrils compared to their traditionally-eating counterparts.
Based on this evidence, and the many photos of the people Price studied, we can hypothesize that the same Native Americans who we read about breathing exclusively through their noses, must have had more robust and effective nasal structures in general. Further, the dietary issues that many of us grew up with and our now resolving with paleo-style diets, left us with poorly developed noses during the most crucial growing periods of the human life-cycle - childhood.
Anaerobic Oxygen Deficit
Anaerobic exercise is exercise intense enough to trigger anaerobic metabolism, where insufficent oxygen is available for oxidation, and the body switches over to the creatine pathway or glycolysis. As long as enough oxygen is available one can stay aerobic, the domain of more moderate or lower-intensity activities. If one is well trained though, they might be able to run at a good pace while staying in that oxygenated aerobic zone.
High intensity activities of more than a few seconds will drive up the demand for oxygen tremendously however, and if activity like this continues for several minutes (like with a CrossFit WOD or sports) then the body will dip into an oxygen deficit. In recovery, oxygen is used in the processes that restore the body to a resting state and adapt it to the exercise just performed. Scientifically speaking, the process is called "excess post-exercise oxygen consumption", but in layman's terms it is simply referred to as "sucking wind".
Your body needs oxygen badly, and in general the least resistant and highest volume throughput entryway for oxygen into your body is your mouth. I always thought I was mentally weak for not holding my mouth shut through a workout, but it seems that my preference for high intensity training put me in a position where nose-breathing was inadequate for my oxygen needs.
If you recall Lieberman's comments above, the turbulence and resistance created by our nose is incredibly useful, but this benefit diminishes when there is a corresponding need for higher-intensity work output. Ultimately, you'll have to decide what is more important to you.
There are definitely advantages to breathing through one's nose. It humidifies the air better, maintains a more constant air temperature, conserves moisture upon expiration, produces nitric oxide for use by the body, and helps protect against foreign pathogens.
For people who suffer from exercise-induced asthma, nose breathing can be a remarkable cure. The underlying cause of this type of asthma appears to be the large volume of cool, dry air inhaled during strenuous exercise. For many, it seems to improve when the air inhaled is more fully humidified and closer to body temperature, something accomplished by the nose.
Unfortunately, it seems that many people may have been inadvertently steered towards predominant orinasal breathing due to poorly developed facial and nasal structures. Even if staying inside the aerobic zone, the volume of air that could be pushed through our narrow noses might never be sufficient for our muscular needs. Further, my preference for high intensity training makes it even less likely that my nose will do me much good.
While aerobic training might be popular for many runners, high intensity interval training systems like Crossfit, and high impact sports like football aren't going anywhere. People will need to accept that there isn't one exalted breathing technique that is appropriate for all occasions. If you can sustain your activity level with your mouth kept shut, that's great, and will probably provide some respiratory health benefits. But if you find you can't keep pace, or tire quickly from a feeling of labored breathing, relying solely on your nose just to satisfy a romantic ideal of prehistoric runners is folly.
No matter how stoic you might be, the suffocating feeling you get is actually your body telling you that you're suffocating. Do yourself a favor and take a deep breath - with your mouth open if need be. It doesn't mean you're weak, or less of an athlete. It just means you need air.