Breath has a strong influence on the way we express movement in yoga. Whether you move on an inhalation or exhalation alters the feeling of a pose and enhances the possibility of expressing a pose more fully. I don't personally believe there is a right or wrong way as long as it enhances mobility.

There has been a debate in the yoga world over whether form follows function, or function follows form. In other words, do we develop our form, our body shape, based on the way we function or do we function based on the way we develop our form? The same can be asked of breathing. Can the way we breathe affect the way we function? Does the form we develop affect the way we breathe?

The answer to both questions is yes. If we alter our breathing, we can improve the way we function and if we change our form, we can breathe more or less easily. Movement and breathing are required in yoga just as a plant requires water to grow.

Respiration is the production of energy via the intake of oxygen and the release of carbon dioxide. Since we cannot store oxygen in the body, we must breathe. The way we breathe effects the levels of oxygen and carbon dioxide within the body at any time and both gases are important. Carbon dioxide actually dilates the blood vessels enabling more oxygen to be absorbed, so the pause at the end of our exhalation serves a vital purpose.

The act of breathing can serve other purposes in our practice depending on circumstances. We can use it:

• To alter tension; either increasing or relaxing.
• To change emotions.
• To accentuate or moderate the curvature of the spine.
• To stimulate the organs.
• To more forcefully open or close the rib cage.
• To accompany another action.

Allow me to elucidate. Commonly we either breathe costally (using the thoracic cavity), opening the rib cage during inhalation and closing them during exhalation, or diaphragmatically (using the abdominal cavity), expanding the belly on the inhalation and contracting it on the exhalation. Neither method is right or wrong and both has advantages.

However, in terms of gas exchange, costal breathing is less efficient than diaphragmatic breathing. The deeper into the body we breathe, the deeper into the lungs we breathe, thereby oxygenating the alveoli with fresh oxygen and by exhaling fully we remove any stale air from the lungs. The more oxygen we inhale, the more energy we give to the cells and in turn to ourselves.

Physically we can alter the breathing between costal and diaphragmatic depending on what result we wish to achieve. Should we have tension in the muscles of the upper back for example,  breathing costally can assist in stretching the muscles whilst the exhalation can ease the tension. If we have our belly suspended beneath us or if we are lying on our backs, it is far more relaxing to breathe diaphragmatically.

As emotions effect the breath, diaphragmatic breathing is thought to be more relaxing since it induces the Relaxation Response that I wrote about in a previous post. The diaphragm is innervated by the Phrenic nerve. This nerve is associated with sleep apnea, a treatment for which is phrenic nerve stimulation. If we choose to focus on diaphragmatic breathing, it also makes sense that we stimulate the phrenic nerve naturally and so avoid or improve sleep apnea, maintaining a healthy rhythm to our breathing.

By changing the way we breathe we can alter our emotional state. When stressed or anxious for example, we start to breathe into the chest with a short, shallow breath. By shifting the breath into the belly, using diaphragmatic breathing, we calm the nervous system and effect the emotions. If we are suffering from lethargy through depression perhaps, we can practice specific pranayama to energise or chanting which can lift the mood.

With every inhalation, diaphragmatic breathing stimulates the organs by squeezing and displacing them, improving digestion. This action also stimulates the Vagus nerve in the same way; this major parasympathetic nerve innervates every organ of our body, therefore diaphragmatic breathing has a more calming affect on the nervous system.

Breathing expansively can help us to elongate the spine. We often find after pranayama practice that we feel taller, especially techniques such as Dirga breath.

Costal breathing can also assist in spinal movements by forcefully opening and closing the rib cage, thereby expanding into such movements as backbending, sidebending and rotation. Whilst forward bending can be improved by diaphragmatic breathing.

And then we have pranayama techniques themselves which can stimulate and energise, calm and relax, balance and cleanse, improve heart rate variation and therefore cardiovascular health.

And finally, breathing is a present moment phenomena. It can maintain our focus on the here and now which is why it is commonly used in meditation.

So what's not to like? Breathing is the real healing component of our yoga practice.