The respiratory system’s primary job is to take in oxygen, transfer it to the blood and, in return, take back carbon dioxide from the blood and release it into the air. Natural breathing takes place through the nose (so particulates can be effectively filtered out) and without noticeable effort — especially on the inhalation. We simply relax, which allows air to whoosh into the lungs, causing them to expand.
What you may not be aware of is that this process of inspiration (inhaling) and expiration (breathing out) also accomplishes two other significant purposes. First, it helps maintain the body’s pH level. It’s a complicated process, but the short version is that if too much or too little carbon dioxide is eliminated, it messes up the body’s acid-alkaline balance. (This is the reasoning behind breathing into a paper bag if you hyperventilate.)
Second, it removes toxins. We don’t usually think of the respiratory system when we think of detoxification, but certain substances are actually eliminated most effectively via the lungs.
When breathing is impaired, we often notice pretty quickly. The struggle to take in air is hard to miss! There are, however, other markers of healthy vs. suboptimal breathing. If you notice your rate of breathing is unusually fast (without an obvious cause, like you’ve just been out for a run), that’s reason to pay attention. If the chest is caving in with each breath, that’s a sign of significant distress. (This is one to watch out for especially with babies/young children.)
Of course turning blue is not normal, and this sign of respiratory difficulty may first appear just around the lips. Breathing sounds should be clear, with no rattling or wheezing, and there should not be any pain. (Breathing hard outside when it’s very cold is a temporary exception. This is often uncomfortable. If discomfort persists after you warm up, pay attention!)
Contrary to common perception, mouth breathing is not normal. It can cause problems with allergies or respiratory illness (due to the absence of filtering mechanisms in the mouth which are present in the nose), and can lead to other issues because of the resultant poor oral posture.