Could mouth breathing be a causal factor in the heart problem that led to Sergio Aguero’s retirement?
Introduction
In October 2021, after only his second start for Barcelona, Sergio Aguero had to be withdrawn early after suffering from chest pains and complaining of dizziness. Recently it has been announced that the 33-year-old will retire from football due to ongoing heart issues related to cardiac arrhythmia. Aguero has arguably had one of the most successful careers in the English premier league. However, it is not without a shadow casting over his footballing skills when retiring from heart health issues at such a young age. Could this have been prevented, or better yet, could his risk of further complications be significantly reduced by looking at his breathing? When looking at pictures of Aguero (figure 1.), there is something consistent, which perhaps to the untrained eye is nothing of significance. However, those who are up to date with their breathing research will spot it from a mile off. Sergio Aguero is a serial mouth breather. Ok, so what? Doesn’t everyone breathe through the mouth?
Yes, many do, but if you’ve read
The Oxygen Advantage by Patrick McKeown and are up to date with the latest science. You will notice that the evidences suggests that breathing through the mouth can cause an array of health issues, and it is not ideal for exercise performance. This article will discuss a potential hypothesis as to why Sergio Aguero and perhaps many other athletes have ultimately led to his career-ending health problems related to the heart: mouth breathing.
Mouth Breathing and the Heart
Mouth breathing not only causes dental issues in children but is also associated with an array of health and behaviour issues [8]. Although mouth breathing gets air into the lungs, it bypasses many of the beneficial effects of nasal breathing. For example, the nose plays an essential role in respiration as it warms, humidifies, and cleanses/filters air to prepare it for delivery to the lung [9]. When comparing ventilation, those who breathe through the mouth typically hyperventilate compared to those who breathe through the nose, leading to a reduction in arterial carbon dioxide (CO2), especially when it comes to exercise [10]. CO2, traditionally thought of as a waste product, is necessary for many physiological processes related to oxygen delivery to working muscles, i.e., the heart. Recent research suggests that CO2 plays a vital role in physiological signalling in breathing and oxygen delivery by a mechanism involving protein Connexin 26 [11]. This specific connexin binds with CO2 and regulates breathing in the medulla oblongata. Connexins are a family of membrane-spanning proteins named according to their molecular weight. They form membrane channels mediating cell-cell communication, which play an essential role in propagating electrical activity in the heart [12]. With mouth breathers typically over-breathing during exercise and at rest, this hyperventilation could reduce the presence of CO2 to bind with connexin, altering levels of this communication protein that over time leads to perturbations in the electrical activity of the heart cells and cardiac arrhythmia.
While this is only speculative, it is not the first hypothesis to suggest issues with mouth breathing and athletes’ cardiac-related health issues. For example, in a recent conversation with Dr George Dallam, a Professor in the Department of Exercise Science, at Colorado State University-Pueblo, he stated a case for Nitric oxide or lack of during mouth breathing being an issue that may cause cardiac scarring in endurance athletes [13].
In this discussion, he states:
“I have a working hypothesis that the relatively more remarkable hyperventilation seen during oral breathing in exercise might be a contributing factor in reduced coronary blood flow – via both a lesser release of nitric oxide (assuming it gets that far downstream from the lung) and generally lower blood CO2 resulting in less vasodilation (maybe even some vasoconstriction) in the coronary arteries. Of course, at rest, significant hyperventilation, as during a panic attack, is associated with occasional coronary spasms and fatal MI in some susceptible individuals. During exercise, similar hyperventilation produced by breathing orally might be the basis for the increased myocardial scarring seen in long term endurance athletes (literally all of whom breathe orally when training/racing).”
