It doesn’t make any sense to exercise with your mouth open. Doing so means you’re initiating short, shallow breaths from the upper chest, which brings most of the oxygen intake into the upper part of the lungs. Whereas if you take slower, deeper breaths through your nose, you’re utilizing the diaphragm and the air is going down into the lower part of the lungs. Due to gravity, a greater volume of blood resides in the lower parts of the lungs than in the upper. Breathing through the nose carries nitric oxide into the lungs to help redistribute blood throughout them. Breathing deeply carries the air into the lower regions of the lungs. A combination of improved blood and air distribution throughout the lungs increases oxygen uptake in the blood by 10 to 15 percent. This means there’s more oxygenated blood going to the muscles that need it and to the brain, which controls motor patterns. This has a significant impact on performance from both a physical and cognitive standpoint.  

We often see mouth breathing triggering conditions like exercise-induced bronchoconstriction. This can manifest itself as asthma, but even if it doesn’t go that far, there’s a narrowing of the airway as smaller passages in the lungs cool and dry out. This results in the child feeling tight in the chest and leaves them gasping for breath, which perpetuates the problem. In contrast, nose breathing filters, warms, and moistens the air, which travels to the lungs via an unrestricted airway. Even for kids without breathing difficulties, we see faster energy consumption and great fatigue among mouth-breathers.

There are studies that show Neanderthals had superb facial structures with wide noses that allowed a larger volume of air to come in. The literature suggests that this was how we breathed for most of our evolutionary history, and that mouth breathing has only become prevalent in the past 400 years. Dr. James Metz, who’s a leading expert in the connection between breathing patterns and facial structure, interviewed a Sherpa about the differences between Westerners and native Tibetans climbing Mount Everest. He noted that the former huff and puff as they move up the mountain, whereas the Sherpas who are not only carrying their own bodyweight but also transporting heavy gear, instinctively breathe through their noses. Yes, they are more acclimatized to the altitude, but nose breathing comes naturally to them.

If you pulled up Google and typed in something like “breathing for running,” a lot of the results would suggest you should be mouth breathing, so there’s a lot of misinformation. Some people justify the advice to mouth breathe by claiming that the volume of air drawn into the body is greater than when nose breathing. But when you dig into the numbers, that doesn’t add up. For example, breathing twenty breaths per minute with a tidal volume of 500 ml amounts to 10 liters of air being drawn into the mouth. Given that 150 ml of each breath remains in the nasal cavity, throat, and bronchi, the amount of air actually reaching the sites of gas exchange in the lungs is 20 breaths times 350 ml, equaling seven liters per minute. Compare this to breathing slowly and deeply through the nose involving 10 breaths per minute, with the size of each breath being one liter. The volume of air drawn into the body is the same: 10 liters. However, due to reduction of dead space, the amount of air reaching the small air sacs is higher during nasal breathing: 10 breaths times 850 ml equals 8.5 liters.  

In addition, during nasal breathing, there is less of a tendency for the body to over-breathe, resulting in a lowering of the gas carbon dioxide. Contrary to popular opinion, carbon dioxide is not just a waste gas. It’s the catalyst for oxygen to be released from the blood to the cells. Breathing too hard through the mouth causes a lowering of carbon dioxide in the blood, resulting in less oxygen being delivered to the cells. It’s ironic that hard breathing reduces oxygen delivery to the cells. From an athletic standpoint, this can have a big effect on speed, strength, and endurance.

On the flip side, if we take this long-term view of instead of worrying about the results right now, we’re focused on doing whatever’s needed to help the athlete grow over the long haul. There’s a greater vision. This will keep someone in the sport for longer and make sure they keep enjoying themselves rather than burning out. It’s also going to get them closer to their optimal potential. It takes years and years to master anything. Examples abound in youth sports particularly. You have these talented kids whose parents are pushing them to train 20 hours a week and they eventually flame out because they specialized too early and there was too much volume. Whereas the kids who dabble in lots of different activities and still have fun on the playground are often those who end up sticking with a sport.

Chronic mouth breathing contributes to a forward head posture, which is already being exaggerated by the use of phones and tablets. If they breathe through their mouth, they can also develop a smaller airway and see a lack of normal forward growth of the jaw, according to experts like John Mew. This can contribute to orthodontic issues that require expensive correction down the road. There’s also research that shows the spinal column changes shape in children who consistently breathe through their mouth. An athlete’s potential isn’t defined by the coaching they receive at age 10 or 15. It’s a question of whether they breathe through their nose or mouth when they’re growing up. A child who consistently initiates mouth breathing from their upper chest and takes their nose and diaphragm out of the equation will be athletically and psychologically disadvantaged.

It’s a perfect illustration of something we struggle with in modern life, which is giving things our full attention and awareness. One of the keys Brad and I have found for people with a mastery mindset is that when they’re focused on doing things that matter, they give it their complete focus. When we’re running around in circles on the track it isn’t boring but rather enthralling when we start to understand all the ins and outs and are mindful of running’s nuances.

We need to put sleep in the picture, too, as this is vital for development and mental health. Sleep quality is directly influenced by breathing. According to a comprehensive paper, if a child is snoring every night by age eight and this isn’t remedied, there’s an 80 percent chance that they could have a permanent reduction in cognitive capacity of up to 20 percent. And if they have sleep-disordered breathing issues earlier on that are not treated by age eight, they’re 60 percent more likely to require special needs education.There’s also evidence that suggests a correlation between nasal obstruction and ADD/ADHD. The good news is that these conditions are correctable without medication or psychotherapy. Often all you need to do is get the child to start breathing through their nose. 

From a coaching standpoint, I know that when I have my phone out or get too fixated on a stopwatch, it halts life and my observational skills decline. I’m not able to pick up subtle changes in form and mechanics or cues of fatigue. It’s like two different planes of reality. You see that in commentary, too. There’s a big difference between a casual fan watching a football game while he’s eating snacks and talking with his buddies and what Tony Romo’s doing. He has so much experience and is so dialed-in that he can call the plays before they actually happen. We can reach that level in the thing we’re passionate about, but only if we’re willing to pay attention and learn to block out distractions.

In practice, the coach could encourage them to keep their mouth closed, take slow, nasal breaths, and keep the tongue on the roof of the mouth to allow for optimal airflow. Ask them to take a breath through their mouth and see how their chest moves. Then have them breathe through their nose and see how their abdomen rises and falls. This is a simple way for them to see the difference in the two breathing patterns. But we can’t just look at what happens during strenuous physical activity. If you have a dysfunctional breathing pattern during rest, it will eventually manifest itself during exercise when you’re exposed to stress. So young athletes should also be advised to breathe only through their noses throughout the day in a slow and controlled manner. This won’t just help them prepare well for sports, but also for life. 

Any parent or coach wanting their young athletes to benefit from nasal breathing can click here to take them through Patrick’s free course. Adults can utilize a 20-minute Buteyko breathing/relaxation exercise here. 

Data for elite female 5K runners shows that before they made their big breakthrough to the Olympian level, most of their times stagnated for two or three years. Then they saw this huge progression of 15 to 20 seconds that got them to the next level. When a lot of people get stuck on a plateau, they get frustrated and quit. But you have to keep going and putting in the work because you never know when your breakthrough could be just around the corner.