Breathing is important because we need oxygen for cellular respiration. This is a process where we convert oxygen into energy. Oxygen comes goes down into the lungs which is then circulated around the body through the bloodstream via red blood cells and then carbon dioxide is released back out through our exhales as a waste by-product. Respiration allows our body to move and function on every level. The diaphragm, a sheet of muscles across the bottom of the chest, is important in respiration as it expands and contracts the lungs to pull in and expel air.
Breathing is part of the autonomic nervous system which the brain controls predominately unconsciously and in particular the heart, and digestion. However, the breathing response is one part of the autonomic system that we can actually regulate and control at will. As a result, this can have an impact on the stress or fight, flight or freeze response. This stress response receives input from the limbic part of the brain where the amygdala is housed. The amygdala is primarily involved in emotional reactions such as fear, anxiety, and aggression – this is often received from outside stimuli or by a perceived external threat either real, or imagined (as in embedded unconscious traumatic memory) and more commonly derives from the daily stress of modern life. The sympathetic nervous system comes into play when our amygdala triggers our stress (fight, flight or freeze) response and our parasympathetic nervous system can be stimulated through many aspects of Yoga, in particular, meditation, relaxation and breath control (pranayama). Our breathing works in tandem with our heart and when our breathing pattern changes, our heart’s activity does too. For example, it will slow down when we practice deep diaphragmatic breathing, which triggers the sympathetic or rest and digest response in the nervous system. The sympathetic signal achieved through slow deep Yoga breathing brings the pre-frontal cortex back on line from an amygdala high-jack of the stress response. The prefrontal cortex is associated with executive functioning – rationality, focus, concentration, emotional control and hence the ability to create a relaxed mental state. Those who are suffer from being in a constant stressed and sympathetic state are not in rest, digest and repair mode. This repair mode is important as when it is compromised it causes significant wear and tear to the body, for example, heart disease, high blood pressure, depression, anxiety and many auto-immune diseases such as MS, arthritis and IBS.
Stress is associated with creating imbalances in the brain, especially neurotransmitters like GABA, a chemical messenger. It’s associated with relaxation, sleep, and muscle function – it mitigates against the stress-response which triggers inflammation in the nervous system (as indicated above) and the immune system. Yoga releases GABA in the thalamus and is also shown to be significantly higher in the brains of those doing regular yogic breathing practices. In relation to our stress response, the vagus nerve has a significant role to play – it innervates the face, and abdomen, and in particular as it goes through the diaphragm needed for respiration, it can be massaged through deep abdominal breathing . Low vagal tone is correlated with health conditions from low mood to chronic disease and in sum, higher vagal tone is linked to physical and psychological well-being. Vagal tone defines the functional status of the vagus nerve and is the degree of activity within the parasympathetic nervous system (rest and digest, which is the opposite to the stress response: fight, flight and/or freeze). The vagus nerve, which is the 10th cranial nerve and the largest, relays information between the brain and other internal organs, thereby connecting these areas with the nervous system. A better health prognosis is predicted by optimal vagal tone; furthermore, the immune strength and resilience of an individual directly depends on the activity of the vagal nerve. Several research studies suggest that yogic practices such as pranayama, or breathing techniques, can significantly increase vagal tone thus regulating the nervous and immune system. Yoga relaxation practices such as pranayama, direct the body’s energy to repair and immune function (Menzies and Kim, 2008; Benson, 1975). The more important point to make, is that stress begins in the mind: “Every mental state creates a corresponding state in the body, and every action in the body has its corresponding action on the mind” (Swami Vivekananda). The ultimate goal of Yoga is to settle mental disturbances (Yogah chitta-vrtti-nirodhah, The Yoga Sutras 1:2) and this can be done by regulating the breath consciously, which helps to quiet the mind by cultivating present moment attention.