Don’t be a Mouth Breather!

Mouth breathing is common in children and athletes but far from benign. Chronic mouth breathing often accompanies nasal obstruction, allergies, enlarged tonsils/adenoids, or habitual poor oral posture, and it can lead to a cascade of physiological and developmental consequences. Nasal breathing produces nitric oxide (NO), which helps dilate blood vessels, improve pulmonary blood flow, and enhance oxygen delivery. Mouth breathing bypasses this nasal NO production and reduces those respiratory and circulatory benefits. Over time, habitual mouth breathing alters ventilation patterns, increases anatomical dead space, and can make gas exchange less efficient, which undermines oxygen uptake.

The downstream effects on sleep and brain development are particularly concerning as well. Mouth breathing frequently coexists with sleep-disordered breathing (SDB) and nasal obstruction. These disturbances provoke neuroinflammation, and oxidative stress. Mechanisms that have been linked to poorer attention, executive function, memory, and school performance in children. For a developing brain, chronic reductions in sleep quality and intermittent hypoxic episodes can blunt cognitive development and behavioral regulation, making mouth breathing more than an airway or dental issue. It becomes a risk factor for compromised learning and neurodevelopment.

For young athletes, the physiological consequences of mouth breathing directly impair recovery, training adaptation, and on-field output. Poor sleep quality and intermittent hypoxia blunt anabolic signaling (including growth hormone secretion), impaired glucose metabolism, and reduced efficiency of tissue repair, all of which limit muscle recovery and adaptation to training load. Habitual mouth breathing tends to shift autonomic balance towards raising resting heart rate and lowering heart-rate variability. This further inhibits recovery and resilience to training stress.

Beyond physiology and performance, chronic mouth breathing reshapes craniofacial growth and dentition in growing children. Altered tongue posture and lack of a habitual lip seal often produces a long face, narrow maxilla, open bite, and other issues that can compromise airway space and breathing efficiency. These structural changes influence both function and appearance. What many refer to as the “jawline” effect can be difficult to fully reverse if not addressed early. Interventions such as timely orthodontic or maxillary expansion strategies, when indicated, can open nasal passages and improve growth trajectories alongside medical and myofunctional approaches.

Because nasal obstruction and allergic disease are common in children and adolescents, mouth breathing is widespread and frequently overlooked. Youth athletes are especially vulnerable because their training demands heighten the need for efficient breathing, restorative sleep, and reliable recovery. Mouth breathing undermines each of these, and can quietly cap an athlete’s developmental ceiling. Thus increasing injury risk, limiting performance gains, and reducing long-term airway health. Recognizing mouth breathing early is therefore critical: signs include a habitual open-mouth posture at rest, snoring, nonrestorative sleep, daytime sleepiness or attention problems, orthodontic crowding or long-face appearance, and unexplained declines in athletic recovery or performance.

Addressing chronic mouth breathing requires a multidisciplinary, cause-focused approach. First, treat underlying contributors such as allergies or obstruction with appropriate therapy. Breathing retraining work to restore nasal breathing, correct tongue posture, and re-establish a proper lip seal are a few examples. Evidence suggests these approaches can improve breathing patterns, especially when combined with medical or surgical care. Coaches and parents should also prioritize sleep hygiene, adjust training loads while breathing and sleep issues are being treated, and incorporate simple nasal-breathing drills into daily routines.

In short, mouth breathing is more than a nuisance, it is a systemic problem that undermines brain development, athletic output, recovery, and facial growth. Left unrecognized, it can quietly derail youth athletic dreams by reducing training responsiveness and long-term health. Early screening, and integrated interventions (informed coaching practices) can protect both developmental potential and athletic futures.

Sources:

- Gozal, D. (1998). Sleep-disordered breathing and school performance in children. Pediatrics, 102(3 Pt 1), 616–620.

- Gozal, D., & Kheirandish-Gozal, L. (2009). Childhood obstructive sleep apnea and inflammation. Journal of Pediatrics, 154(3), 410–417.

- Lundberg, J. O., Weitzberg, E., & Gladwin, M. T. (2008). The nitrate–nitrite–nitric oxide pathway in physiology and therapeutics. Nature Reviews Drug Discovery, 7(2), 156–167.

- Harari, D., Redlich, M., Miri, S., Hamud, T., & Gross, M. (2010). The effect of mouth breathing versus nasal breathing on dentofacial and craniofacial development in orthodontic patients. Laryngoscope, 120(10), 2089–2093.

- Villa, M. P., Rizzoli, A., Miano, S., et al. (2015). Myofunctional therapy to treat obstructive sleep apnea: a systematic review. Sleep and Breathing, 19(3), 665–676.

- Row, B. W., et al. (2008). Intermittent hypoxia and brain injury: molecular mechanisms and behavioral consequences. American Journal of Physiology.

- Van Cauter, E., & Plat, L. (1996). Physiology of growth hormone secretion during sleep. Journal of Pediatrics.