Taking a deep breath through your nose relaxes your body and calms you down. On the other hand, regularly breathing through your mouth can keep you in a state of minor stress. — Positive Parenting
Breathing is something we do about 20,000 times a day, often without giving it a second thought.
Yet, this simple act has a powerful influence on our health, energy, sleep, and even mood.
What many people don’t realise is that how we breathe matters just as much as how much we breathe.
Our bodies are designed for nasal breathing, not mouth breathing.
The nose is far more than a hole in the face; it’s an advanced filtering, humidifying and oxygen-optimising system.
It prepares the air before it reaches your lungs and ensures every breath supports your body in the best way possible.
In contrast, breathing through the mouth may seem harmless, but over time, it can affect your sleep, oral health, energy levels, and even your facial structure.
Let’s take a closer look at why the nose is nature’s preferred pathway for breathing, and what happens when we neglect it.
A built-in air filter
Think of your nose as your body’s first line of defence.
Inside the nasal passages are tiny hairs called cilia and a thin layer of mucus, which, together, act like a natural filter.
As air passes through, dust, pollen, bacteria and other airborne particles get trapped and prevented from entering your lungs.
When you breathe through your mouth, you skip this vital step.
Unfiltered air flows straight into your throat and lungs, bringing in irritants and microbes that can cause infections or worsen allergies.
Over time, this can lead to more sore throats, coughing and respiratory discomfort.
Climate control
Beyond filtering, your nose also acts as a climate control system for your breath.
As air travels through your nasal passages, it is warmed, moistened and gently regulated before reaching the lungs.
This matters more than most people realise.
The lungs are delicate organs that function best when the air is warm and humid.
Breathing cold, dry air through the mouth can irritate the airways, causing coughing, or even mild inflammation, especially in people with asthma or sensitive lungs.
Nasal breathing also helps prevent that “scratchy throat” or dryness you feel after sleeping with your mouth open.
Nitric oxide production
One of the nose’s most fascinating secrets is that it produces a small, but mighty, molecule called nitric oxide (NO).
This gas mixes with the air you inhale and plays a crucial role in improving oxygen delivery throughout the body.
Nitric oxide helps to open up blood vessels, allowing oxygen to circulate more efficiently.
It also has antibacterial and antiviral properties, which means it helps fight off germs even before they reach the lungs.
When you breathe through your mouth, you lose this benefit entirely.
Mouth breathing not only bypasses nitric oxide, but also often leads to shallow, fast breathing, which reduces your oxygen efficiency.
The result is a body that may still feel tired, foggy or anxious, even when you’re technically breathing “enough”.
Calming down
If you’ve ever been told to “take a deep breath” when you’re stressed, then know that there’s science behind that advice, especially if that deep breath is through your nose.
Nasal breathing naturally slows down your breathing rate and activates the parasympathetic nervous system, which helps calm the body and mind.
Mouth breathing, on the other hand, often triggers the sympathetic (“fight or flight”) response, which can make you feel tense or anxious.
Over time, chronic mouth breathing can actually keep your body in a mild state of stress, contributing to fatigue, poor focus, and even higher blood pressure.
This is why practices such as yoga, meditation and tai chi place so much emphasis on nasal breathing – it’s not just about oxygen, but also about restoring balance to the nervous system.
Promoting better sleep
How you breathe during the day affects how you sleep at night.
People who breathe through their noses tend to sleep more soundly, because nasal breathing supports proper airflow and prevents airway collapse.
Mouth breathing during sleep often leads to snoring, dry mouth and poor oxygen levels.
You may wake up tired, groggy or with a sore throat.
Over time, it can even increase the risk of sleep apnoea, a condition where breathing repeatedly stops and starts during the night.
ALSO READ: Mouth taping to prevent snoring is a potentially risky practice
Encouraging nasal breathing – sometimes with the help of posture adjustments, nasal sprays or gentle breathing exercises – can make a huge difference in sleep quality and overall energy.
It’s one of the simplest, most natural ways to wake up feeling refreshed.
Maintaining oral health
Your mouth is meant for eating and speaking, not breathing.
When you breathe through your mouth, it dries out your saliva, which is essential for neutralising acids and washing away bacteria.
A dry mouth becomes a breeding ground for bad breath, tooth decay, gum disease, and even mouth ulcers.
ALSO READ: When your mouth is constantly dry
In children, chronic mouth breathing can interfere with jaw and facial development, leading to a longer, narrower face and misaligned teeth – what dentists sometimes call a “mouth breather’s face”.
Nasal breathing keeps the mouth closed and moist, maintaining the right balance of bacteria and protecting your teeth and gums in the long term.
Better sports performance
Whether you’re an athlete or just someone who likes to stay active, nasal breathing can help you perform better and recover faster.
When you breathe through your nose, you take slower, deeper breaths, which improves oxygen delivery to your muscles and helps you maintain endurance.
In contrast, mouth breathing tends to make you breathe too fast, lowering carbon dioxide levels and reducing oxygen uptake.
That’s why mouth breathers often feel fatigued or dizzy during workouts.
Many endurance athletes now train themselves to breathe through their noses as much as possible – even during intense exercise – to improve stamina, focus and recovery time.
ALSO READ: Learn how to breathe properly for exercise and to relax
A forced habit
Sometimes, people resort to mouth breathing because of underlying issues, e.g. nasal congestion, allergies, sinus infections, or structural problems such as a deviated septum or enlarged tonsils.
While mouth breathing might provide temporary relief, it’s important to identify and treat the root cause.
Persistent mouth breathing can worsen the problem over time, leading to chronic congestion, poor sleep and fatigue.
Simple solutions like saline rinses, allergy management, nasal decongestants or breathing retraining therapy can often restore healthy nasal breathing and improve overall quality of life.
Breathing naturally again
The good news is that it’s never too late to retrain bad breathing habits.
Simply paying attention to your breath throughout the day, especially during times of stress, rest or physical activity, can make a noticeable difference.
Start by consciously keeping your mouth closed and inhaling slowly through your nose.
You can also practise slow nasal breathing exercises, where you inhale for four counts, exhale for six, and pause briefly before the next breath.
Over time, your body adapts and nasal breathing becomes second nature again.
If you find it difficult to breathe through your nose due to congestion, seek advice from a healthcare professional.
Treating sinus issues, allergies or nasal obstruction can restore natural breathing.
Breathing through your nose isn’t just a small habit; it’s a foundation for good health.
Mouth breathing, though sometimes unavoidable, is best reserved for short-term situations like intense exercise or temporary congestion.
When it becomes a habit, it can disrupt sleep, oral health, and even emotional balance.
ALSO READ: Are you a mouth or nose breather? Mouth breathing could impact your health
By simply closing your mouth and letting your nose do its job, you can improve your energy, sleep, focus, comfort, appearance, long-term health and well-being in profound ways – one mindful breath at a time.
Datuk Dr Nor Ashikin Mokhtar is a consultant obstetrician and gynaecologist, and a functional medicine practitioner. For further information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
