Inhaling, exhaling and pausing your breath influences your autonomic nervous system. Basically, the autonomic nervous system includes the sympathetic system which activates the “flight or fight” response, while the parasympathetic system activates the “rest and digest” response.

Inhalation from the “bottom up” such as a gasp in breathwork is a sympathetic signal. This often happens when breathing in through the mouth.

Exhalation such as a sigh or release of breath from the mouth.  You might find yourself doing this when you are relaxed, satisfied, or relieved.

Breath holds, also known as kumbhakas, breath holds or apneas and are powerful autonomic nervous system signals.

A long breath hold with a full lung acts as a sympathetic trigger (flight or fight) and allows for a long gas exchange in the lungs.

A neutral lung where a person exhales air without forcing all of it out with diaphragm generally promotes a parasympathetic trigger to rest and relax the body.

The empty lung  also known as Bahya Kumbhaka occurs when a person truly empties the lung.  This is rare and uncomfortable and is very difficult to do for very long.

The urge to breathe is from a buildup of carbon dioxide (CO₂) in the body. When we breathe, our body undergoes cellular respiration. This is the process when our cell’s mitochondria (energy center) create adenosine triphosphate (ATP) also known as cellular energy.  The mitochondria consume glucose (sugar) and oxygen (O₂) to produce energy in the form of ATP where one of the byproducts is CO_2. When we detect an uncomfortable level of CO_2, we feel the urge to breathe, while our O₂ saturation generally does not dip significantly.

A higher tolerance to CO₂ is beneficial and can be explained by the Bohr Effect.  Anyone can increase or decrease the amount of CO₂ they can tolerate before feeling the urge to breathe over time.  A higher level of CO₂ in the blood causes the red blood cells to deliver more O₂ to the tissues.  When CO₂ levels are lower, red blood cells bind too strongly to O₂ to deliver it to your tissues.  Christian Bohr described this inverse relationship in 1904.  The take away here is that when you have low CO₂, your red blood cells will not as readily release the oxygen that they are carrying, depriving your tissues of oxygen. This can make you feel tired and fatigued because O₂ is not being delivered efficiently.  CO₂ and nitrogen oxide (NO) signal the red blood cells to know where to deliver the O₂ via the Bohr Effect.  NO is a powerful antioxidant and is important in the Bohr Effect. Therefore, a person with a high tolerance for CO₂ is capable of performing physically demanding activities longer than someone who has a low tolerance.  This is why most athletes work hard to increase their CO₂ tolerance and also are great practitioners of breathwork! So, if you are not an athlete, why should you care about your CO₂ tolerance?  A person with low CO₂ tolerance will take more breaths per minute than one who has a high CO₂ tolerance and this can send your body into a “flight or fight” response. Since your autonomic nervous system is always “listening” and will promote faster breathing and an increased amount of stress hormones in your body. This can lead to anxiety, panic, hypertension, chronic tension, pain, inflammation and disease.

The good news is that you can train your body to breathe in ways to stimulate your parasympathetic system to feel more peaceful and relaxed while reducing anxiety and the production of stress hormones in the body! Learning to breath in and out through the nose and from the diaphragm instead of the chest promotes wellness each day.