Breathing through the mouth is bad for your health: Here is what experts know

Many people may be struggling with their overall health and do not know that a simple habit like mouth breathing, which happens when you keep your mouth open and can't breathe through the nose, may be to blame. Mouth breathing, especially during sleep, could be silently harming their health. Experts link it to reduced oxygen, dehydration, fatigue, reduced brain activity, among other issues. Mouth breathing can reduce oxygen intake by up to 20%, leading to poor sleep, reduced concentration, and slower brain development, especially in children, according to researchers. Left unaddressed, this habit can cause a ripple of health complications. Mouth or nose breathing: What's the difference? Mouth breathing refers to inhaling and exhaling through the mouth instead of the nose. Unlike the nose, the mouth isn’t designed for respiration. The nasal passages filter out dust and allergens via tiny hairs called cilia and warm and moisten incoming air using internal structures called turbinates. This preconditioning ensures the lungs receive clean, humid air at body temperature, which is crucial for optimal respiratory function. In contrast, mouth breathing bypasses these protections, exposing one's body to dry, unfiltered air that irritates the lungs and throat. Mouth breathing may solve the immediate and essential problem of getting enough air. But it can become a hard-to-break habit. According to a review in the International Journal of Community Medicine and Public Health, mouth breathing is prevalent in 5–75% of children. One key trigger is nasal obstruction. Batamuliza Kaitesi, an ear, nose and throat (ENT) specialist at Humanhood Clinics in Kigali, explains that the causes of mouth breathing vary but often involve anything that blocks the nasal airways. “In children, mouth breathing is commonly due to nasal congestion from frequent colds, allergies, or enlarged adenoids,” she told The New Times. “Enlarged adenoids (glands located in your upper airway) can narrow the nasal passage, forcing the child to breathe through the mouth.” She also flagged alcohol consumption before bedtime as a risk factor for mouth breathing, noting that it relaxes the throat and mouth muscles, increasing the likelihood of snoring during sleep. Other causes include sinus infections, nasal polyps, deviated septum, or structural abnormalities. These conditions, if left untreated, can disrupt normal nasal airflow and lead to chronic mouth breathing. Hidden health risks Mouth breathing may appear harmless, but research shows it can trigger a chain of health problems. A 2025 study by the Turkish Thoracic Society linked mouth breathing to reduced brain activity in areas responsible for memory, learning, and basic arithmetic. Children who breathe through the mouth often perform poorly in academics compared to nasal breathers, the study found. One's facial structure can also be affected. “Children, who mouth breathe can develop what we call ‘adenoid face’ or ‘long face syndrome,’” said orthodontist Eric Mugabo. “This includes narrow facial features, receding chins, and misaligned teeth caused by altered tongue posture and jaw positioning.” Mouth breathing has also been linked to reduced nitric oxide, essential for muscle recovery, blood circulation, and maintaining energy throughout the day. This deficit may lead to dizziness, fatigue, and poor physical performance. Dr. Eric Shumbusho, a general practitioner at Butaro Level Two Teaching Hospital, noted that mouth breathing during sleep can contribute to poor sleep quality like sleep apnea, a serious condition where breathing repeatedly stops and starts due to low oxygen levels. “This disrupts rest and can lead to behavioural problems and learning difficulties,” he said. Mouth breathing can even lead to greater water loss. A 2020 study by Acta Scientific Dental Sciences revealed a 42 per cent increase in water loss when people breathe through their mouths compared to their noses. This dehydration contributes to dry mouth, sore throat, bad breath, and even drooling during sleep. Over time, mouth breathing can dry out oral tissues and lead to gingivitis, a gum inflammation marked by redness, swelling, and bleeding. If left untreated, this can escalate into periodontitis, potentially causing permanent tooth loss. How to correct mouth breathing Experts say prevention begins with identifying and treating the root cause of mouth breathing. “In most cases, a blocked nose forces people to switch to mouth breathing,” said Dr. Kaitesi. “That’s why treating conditions like allergies, sinus infections, or enlarged adenoids is crucial.” She recommends managing weight, as excess fat can narrow airways, particularly during sleep. Regular exercise and good nutrition support healthy breathing patterns. Environmental factors also matter. Sleep hygiene, like maintaining a clean, dust-free bedroom, helps reduce nasal irritants and supports better breathing,” she added. Stress management and conscious breathing exercises can also help. “Practice keeping your mouth closed during the day, and support your neck with a pillow while sleeping to open up nasal passages,” Dr. Shumbusho suggests. Staying hydrated is equally important. Drinking enough water helps keep nasal tissues moist and supports saliva production, which protects against tooth decay and bad breath. Dental professionals like Dr. Mugabo stress early detection, especially in children. “Correcting dental malformations at the right age is key. ENT and dental specialists must work together to address the underlying causes,” he said. He also added that parents should be keen observers of their children if they are mouth breathers and identify this earlier to seek medical assistance. Mouth breathing may seem minor, but over time, it can quietly erode both physical and cognitive health. Experts agree that early detection and proper treatment aren't just helpful; they're essential to maintaining quality of life and healthy development, especially in children.

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Breathing through the mouth is bad for your health: Here is what experts know