Breathing through the nose (instead of the mouth) filters, warms, and humidifies the air. Nasal breathing also promotes correct tongue posture and jaw growth. Chronic mouth breathing, on the other hand, can narrow the airway, increase the risk of sleep problems, and affect dental and facial development. Airway restriction in children is not just a breathing problem—it’s a whole-body issue. It affects craniofacial growth, sleep quality, metabolism, and oxygen delivery, which in turn influence learning, behavior, and emotional health. Addressing airway health early (through myofunctional therapy, orthodontics, ENT interventions, or habit correction) can prevent long-term physical and psychological consequences.