From Mona Lisa to Your Child: The Golden Ratio of Healthy Breathing
Why Leonardo’s Portrait Still Feels Alive
The Mona Lisa has been studied for centuries for her symmetry, calm gaze, and famously closed mouth. But what if what Leonardo captured wasn’t just beauty — what if it was physiology?
Leonardo understood proportion. His drawings, from the Vitruvian Man to his anatomical studies, reveal an obsession with ratios — the “golden ratio” in art, architecture, and the human form. But proportion isn’t only visual. In the body, there’s also a physiological golden ratio: the balance between oxygen and carbon dioxide, between form and the functions that sustain it.
The Mona Lisa’s face shows signs of that balance.
Form Follows Function — Literally
Traditions from India, Greece, and Indigenous cultures all recognised that external form mirrors internal health. In the face, this isn’t metaphorical — it’s bone, muscle, and tissue shaped by internal forces.
In healthy nasal breathers, the tongue rests on the palate, pressing outward on the maxilla. This balances the inward pull of the cheeks, keeping the upper jaw wide and rounded. The result: expanded cheekbones, stable eye sockets, and harmonious proportions.
Orthodontic researcher Dr John Flutter notes that two-thirds of the eye socket floor is formed by the maxilla. When underdeveloped — as in chronic mouth breathing — the orbits lose support, cheekbones flatten, and the midface narrows.
The Skull Shapes from the Inside Out
The skull’s 29 bones are pushed outward during growth by the brain, eye orbits, and constant soft tissue pressure. These bones remain responsive to posture, gravity, and how internal pressures are distributed.
With nasal breathing, pressures expand evenly and sinuses remain proportionate. In chronic mouth breathing, over-breathing reduces CO₂, tightens smooth muscle, swells nasal mucosa, and narrows airways. Bone growth is disrupted, producing the “big-headed, dribbly” toddler whose maxillae and orbits lack proper support.
Posture, Eye Orbits, and Cranial Growth
Chronic mouth breathing will tip the head back, shifting the weight of the brain and cerebrospinal fluid inside the skull back to the occiput and taking the orbits with it. Over years, this alters how the face develops. Because the maxilla forms much of the eye socket floor, its position directly affects eye support.
Dr Flutter has shown that correcting nasal breathing in childhood can level the head, rebalance the cranium, and restore healthier growth in the face and jaws. The Mona Lisa’s head is level, her gaze steady — no forward head posture, no cranial tilt.
Sleep and growth
Clear nasal breathing supports deep, uninterrupted sleep. Obstructed or fast breathing leads to snoring and fragmented rest.
Deep sleep is when growth hormone — and gender-determining hormones — are secreted. Poor sleep reduces both, impairing repair and development. Proportionate growth depends on healthy airways.
Facts to consider:
Growth spurts often coincide with clearer airways.
Growth hormone drives bone, muscle, and tissue repair.
Gender-determining hormones are released in deep sleep.
The Golden Rule of Breathing
The body’s “golden rule” for breath is balance: enough oxygen in, enough carbon dioxide (CO₂) retained. Over-breathing blows off CO₂, which the nervous system treats as an emergency.
CO₂ is not waste. At about 40 mmHg in arterial blood, it relaxes airway and blood vessel walls, keeps nasal passages open, and ensures steady blood flow to brain and organs. This is the foundation for calm, oxygenated tissues.
At rest, healthy breathing is slow and silent — about one breath every six seconds. This allows the tongue to rest on the palate, keeps muscles relaxed, and preserves the pressures that guide facial growth.
Asthma and Eczema
Asthma is one visible consequence of over-breathing. Loss of CO₂ causes smooth muscle in the airway walls to constrict, narrowing passages, trapping air, and driving mucus production and coughing.
Asthma is also linked with eczema, another expression of the same imbalance. When CO₂ falls, smooth muscle in both airways and blood vessels constricts, pushing blood toward the skin and leaving it overheated.
Over time, the skin dries and micro-cracks form. Bacteria normally harmless on the surface infiltrate deeper layers, mast cells release histamine, and antibodies flood in. Scratching then embeds bacteria further, creating a cycle of irritation, infection, and chronic inflammation.
Sensitive skin, reactive skin, and even acne often reflect the same underlying physiology.
Why It Matters for Children Now
As a population, we are breathing faster than ever before — not from parental neglect but from modern conditions: less activity, more indoor time, lower muscle-to-bodyweight ratios, and higher allergen exposure.
This isn’t about blame. It’s about awareness.
Encourage children to breathe through the nose and consciously slow their breath. Chronic mouth breathing alters posture, facial proportions, and long-term organ function. “Form follows dysfunction” just as reliably as form follows function.
The Mona Lisa shows another possibility: a calm, proportioned face, grown under healthy internal pressures. Leonardo didn’t just paint beauty; he painted the golden ratio of breathing.
Breathing Before Braces
Orthodontic work can align teeth, but without correcting breathing, results will relapse. Breathing comes first: slow, nasal, lips closed, tongue on the palate.
Treating the nose is essential, but even before nasal clearance, breathing rate must be addressed. Over-breathing depletes CO₂ and locks the body in a stress state, even with an open airway.
Healthy breathing creates the pressures that guide jaws, palate, and facial bones — and supports lifelong health. Without it, orthodontics and medicine alike are working uphill.
About the Author:
Catherine Broué is a systems physiologist. After two decades in ICU and dialysis, she turned to the deeper question of real health, guided by mentors and the insights of Bohr and Buteyko. Her work centres on the body’s true regulators — breath and the central nervous system — and the return to parasympathetic dominance.