As humans, we have developed the ability to breathe in and out through the nose or mouth. Although numerous medical studies indicate the benefits of nasal breathing and the disadvantages of mouth breathing (Lörinczi et al. 2024, 2), approximately 30-50% of the adult population still breathe through the mouth (Allen 2015, 40). Also, research suggests that more than 50% of school-aged children are long-term mouth breathers (Lörinczi et al. 2024, 2).
But does our ability to choose if we breathe nasally or orally have any significant impact on our health? Let’s see.
The nose was designed for breathing and smelling. It provides an entrance for air to enter and exit the respiratory tract, contains the olfactory organ (sense of smell), and is part of the airways that transport air down to the lungs and alveoli (www.britannica.com/science/nose). The internal structure of the nose controls and regulates the direction and speed of the air. This means it properly interacts with a network of arteries, veins, lymphatics and nerves, as well as the mucus blanket in the nasal cavity. Importantly, when air passes in through the nose and nasal cavity it gets filtered, warmed, and moistened and is properly prepared for the lungs (Allen 2015, 40-41). The benefits of breathing through the nose include:
- Slower breathing and heart rate;
- Increased blood oxygen (10-20%) levels;
- Improved lung volume;
- Reduced chance of colds, hay fever and coughing;
- Better use of diaphragm and other respiratory muscles (better stabilisation of the spine);
- Increased activation of parasympathetic nervous system (rest and digest);
- Reduced chance of sleep apnoea;
- Increased elasticity and strength in lungs
(see Allen 2015, 41; Lörinczi et al. 2024, 2; Tiwari and Bhavsar 2024).
One of the less well known, but perhaps most important, advantages of nose breathing is its association with nitric oxide (mighty molecule). Inside the nasal cavity are bony shelf-like structures called turbinates. These slow the air down as it enters the nose and allow it to mix properly with nitric oxide (produced in the nasal sinuses). The nitric oxide is transported with the air down to the lungs and alveoli. Here, it improves oxygen uptake through a process known as vasodilation. Nitric oxide is also antiviral and antibacterial (Allen 2015, 41-42; Lörinczi et al. 2024, 2).
So, the nose is specifically designed for breathing and for ensuring air is properly and optimally prepared for the lungs. Breathing through the nose has numerous advantages including allowing the transportation of nitric oxide into and throughout the body.
But what about the mouth? The mouth is not designed for breathing. It is designed for eating, drinking, and speaking (Allen 2015, 40). If we breathe through the mouth, we bypass the internal structures and elements of the nostrils and nasal cavity. Air is not properly and optimally prepared for the lungs: it is not filtered or moistened, or at the correct temperature, speed, or pressure. Long-term mouth breathing impacts negatively on the respiratory system and the body’s overall health, and can have the following negative health consequences:
- Unfiltered and poorly humidified air entering the lungs at the incorrect temperature and pressure;
- Increased chance of chest breathing (less efficient and more tiring than abdominal/diaphragmatic breathing);
- More chance of sleep apnoea;
- Increased likelihood of bad breath and gum disease;
- More problems with the jaw, palate, and teeth;
- Increased chance of trauma and inflammation to soft tissues in the airways;
- More speech and swallowing problems;
- Increased chance of asthma
(see Allen 2015; Dallam and Kies 2020; Jefferson 2010; Lörinczi et al. 2024; and Munoz and Orta 2014).
In summary, nose breathing has many short- and long-term advantages over mouth breathing. So, whenever possible, try to breathe through the nose.
This can be more difficult than it sounds, though, and often requires retraining yourself how to breathe correctly. One of the best ways to do this is through pranayama (Allen 2015, 42).