Breathe through your nose! This applies to everybody, everywhere and at any time. There are numerous reasons for this, but here follows a physiological and very tangible explanation.
In 1998 the Nobel Prize in medicine was awarded to three American scientists for their discovery of nitrogen oxide's ability to expand blood vessels. This phenomenon is called vasodilation. Nitrogen oxide (NO) simply makes the blood vessel walls relax thereby increasing blood flow.
In 2002 a research group from Karolinska Institutet in Stockholm, Sweden, found that NO is formed and released in human sinuses. Further they showed that the NO concentration in the nasal cavity increases as much as 15 times if you make a "buzzing sound", because it creates vibrations, which mixes air from the sinuses with nasal air.
Their ingenious experiment discovered that blood is oxygenated 10-15% more, when you breathe through the nose compared to breathing through your mouth. When you breathe through your nose, NO flows with the inhaled air into the lungs where it makes the blood vessels in the alveoli expand. This allows a greater volume of blood to pass, whereby more oxygen can be taken up. When NO was given to those who breathed through the mouth, the same effect was registered. This showed that it is actually NO which mediates the marked rise in oxygenation.
It is problematic when people breathing through a respirator have a tube fitted directly to their trachea, because the nose is bypassed. In the study a simple pump sucked air from one of the nostrils of the patient and mixed it with the air of the respirator, which increased oxygenation of the blood by 10-20%.
This study firmly establishes the importance of breathing through the nose, but it is also another beautiful example of how easily and cheaply a standard treatment can be modified and improved. Likewise, it illustrates that treatment with air or pure oxygen may not always be the best solution. Treatment-wise, it is not only patients using respirators that can benefit from NO’s ability to widen blood vessels. It also applies to patients suffering serious chronic illnesses such as high blood pressure (hypertension), pulmonary complications, cardiovascular diseases or those who have suffered a stroke.
A 1000 year old remedy
NO is also one of the active ingredients of nitroglycerine that is used as a heart medicine because it causes the blood vessels of the heart to relax and expand.
You may be familiar with the fact that heart patients, if feeling ill, can place a nitroglycerine pill under their tongue, because this compound rapidly enters the blood stream through the mucosa. How long this procedure has existed in the West is unknown, but it was described in Chinese medicine about 1,000 years ago. The recipe was discovered in a Buddhist cave at Dunhuang, and some of the scripture reads: “Putting under the tongue, to cause heart qi to flow freely. For treating symptoms such as struck by evil, acute heart pains and cold in the hands and feet which can kill a patient in an instant. (…) This is a sure cure.” Note that the scriptures use the term qi, which is identical with the Indian concept of prana – life energy, the power of the universe. Here the expression is used in a very specific context, and it makes sense since qi is precisely the energy that allows a terminally ill patient to regain vitality. This is a perfect example of East meeting West in the true spirit of yoga – even if it took 1,000 years to build this bridge!
In addition, it should also be mentioned that NO has many other beneficial effects. It has a strong antibacterial effect, and can kill both bacteria and viruses. Indeed, studies have shown that NO successfully eliminates bacteria such as Salmonella and Shigella as well as other bacteria that often affect patients with pulmonary diseases caused by smoking or cystic fibrosis. Thus, the effect is not limited to an improved oxygenation of blood: the immune system is also spared and strengthened.
Furthermore, NO also has an amazing property, which reduces oxygen consumption of the cells without compromising the overall energy production. This quite peculiar quality is obviously beneficial to anyone, but particularly to people who are sick and need to optimize oxygen utilization in every conceivable way to become healthy quickly.
Exploiting the properties of NO
The gas molecule nitrogen oxide (NO) that we know is activated through the nose also contributes to relaxation and to expand blood vessels, like carbon dioxide. Add to this an antibacterial function, which can help to improve local conditions in an irritated lung. To further increase the concentration of NO – and thus the dilation of blood vessels – humming sounds during nose breathing can advantageously be employed. This rather special kind of breathing is beneficial because the buzzing sound has been shown to increase the concentration of NO in the nasal cavity up to 15 times, since the air in the nose more readily mixes with NO-rich air from the sinuses.
Moreover, the simple pressure equalizing Valsalva maneuver can help as it presses air from the lungs to all the cavities in the skull, and there are indeed a lot around the nose and forehead. During a strong cold or if you have swum under water with a blocked nose, you may have experience a marked pain in the sinuses. The Valsalva maneuver is easy to perform and everyone can perform it right away, because it requires no prior knowledge. Close your mouth, pinch your nose shut and push air up in your head using your diaphragm and abdominal muscles. You may be able to hear air whistling through the eustachian tubes to the eardrum (psssttt).
The technique is widely used in diving, flying, mountain driving or in any instance where you need to equalize the pressure in your ears. If you maintain the air from the lungs in your head for 20-30 seconds after the Valsalva maneuver, a substantial amount of NO is added to the air, which can then be drawn into the lungs.