It’s well understood that breathing is essential to life. While it’s important to understand the basics of respiratory physiology, there’s much more that we can know and understand about breathing and how the way we breathe affects our physical, mental, and emotional well-being.
Many integrative practices—mindfulness meditation, yoga, Tai Chi, Qigong, progressive relaxation, and guided imagery— incorporate breathwork as a key component or technique. Modern science is just beginning to understand what the wisdom traditions of Buddhism, Yoga, and Traditional Chinese Medicine (TCM) have known and taught for thousands of years: that breathing is the gateway to the body, mind, and soul. In this post, we will explore how and why breathing regulation is beneficial to health and wellness.
Ancient Traditions and Breathing Practices
The late Buddhist monk Thich Nhat Hanh explained that the Buddha’s teaching on breathing includes sixteen methods of inhaling and exhaling combined with mindfulness of the body, feelings, thoughts, and environment (everything outside of the self).
The sage Patanjali compiled the Yoga Sutras over 2,500 years ago. The Sutras introduced the eight limbs, or stages, of yoga, which all yogis are instructed to practice to achieve enlightenment. The fourth limb is Pranayama, or the practice of breath regulation. Pranayama involves controlling inhalation, breath retention, and exhalation and includes techniques such as alternate nostril breathing. Pranayama techniques are often incorporated with yoga asana (posture) practice. Many of yoga’s health benefits can be attributed to the practice’s effect on down-regulating the sympathetic nervous system (SNS) response to stress.
Tai Chi and Qigong are two therapies of TCM. Both incorporate movement and conscious manipulation of the breath. These biofeedback practices reflect the philosophies of TCM—recognizing the body as a whole, focusing on preventive health maintenance, and promoting the body’s healing ability and balance of the individual’s innate energy or ‘qi.’
Posture and Breathing Mechanics
The diaphragm and external intercostals are the primary muscles of inspiration. Normal expiration is a passive process due to the elastic recoil of the lungs and chest wall. Muscles that assist with breathing during active inspiration and expiration are termed accessory muscles and include those in the neck (sternocleidomastoid and scalenes), the internal intercostals of the rib cage, the abdominal muscles, and other muscles attached to the upper limbs and thoracic cage.
Poor posture is associated with dysfunctional breathing patterns and reduced functional respiratory capacity. Slumping and slouching, also known as kyphosis or a curved upper back, compress the rib cage into the abdomen, limiting full diaphragmatic and chest wall movement. Lordosis, or an exaggerated lumbar curve, also limits the full range of motion of the diaphragm by shortening the accessory muscles of the spine. Forward head posture, commonly seen in those using mobile devices, reduces diaphragmatic strength, possibly due to entrapment of the phrenic nerve, which controls the diaphragm.
Both tightness and weakness in the chest, abdominal, and lower back muscles contribute to dysfunctional breathing patterns, limiting chest wall and diaphragmatic movement and reducing the ability to match respiratory effort to metabolic needs during strenuous activity.
All ancient traditions focus on achieving proper postural alignment with a neutral spine while developing an awareness of breath. The movement practices of yoga, tai-chi, and Qigong improve the strength and flexibility of muscles used for proper posture and breathing, increasing chest wall expansion and improving respiratory function.
Autonomic Regulation
The autonomic nervous system (ANS) regulates multiple body functions, including heart rate, breathing, blood pressure, pupil constriction or dilation, digestion, urination, and thermoregulation. Breathing is one of a few of these functions that are also under conscious control, and this bi-directional communication is what we call the mind-body connection.
The ANS is anatomically and functionally divided into two branches: the SNS and the parasympathetic nervous system (PNS). Activation of the SNS, also known as the fight-or-flight response, prepares the body for strenuous activity. Activation of the PNS is the relaxation response, also known as rest and digest, which controls basic bodily functions. Many tissues of the body are innervated by both sympathetic and parasympathetic fibers, either enhancing or inhibiting target organs.
Normally, parasympathetic tone is higher than sympathetic tone, allowing our body to conserve and store energy. When exposed to a threat, the SNS is activated, producing increased heart rate and blood pressure, respiration and bronchodilation, dilated pupils, and blood flow to skeletal muscles. These changes take place due to the direct innervation of target organs and tissues. Stimulation of the adrenal glands causes the release of epinephrine (adrenaline) and norepinephrine. These catecholamines circulate throughout the body in the bloodstream, prolonging and enhancing the effects of the initial direct stimulation.
Following the initial SNS activation, the hypothalamus activates the second stage of the sympathetic response: the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is responsible for releasing cortisol and a cascade of other hormones. Ideally, catecholamine and cortisol levels fall when the threat passes and the body returns to resting and digesting. However, if stress is frequent or chronic, the HPA axis stays activated, and epinephrine and cortisol levels remain elevated – contributing to many diseases, including hypertension, heart disease, stroke, and diabetes.
Regulating Autonomic Reflexes
Autonomic control centers are located in the hypothalamus and brainstem. These reflexes are influenced by higher brain centers, specifically the cerebral cortex (our thoughts) and limbic system (our emotions). Developing awareness and control of the breath is like learning to speak the ancient language of the ANS. In this famous quote, holocaust survivor Viktor Frankl explains how:
“Between stimulus and response, there is a space. In that space is our power to choose our response. In our response lies our growth and our freedom.”
Mindfulness is a top-down approach to autonomic regulation, using the space between stimulus and response to allow one to choose a wise reaction over an unstoppable reflex. Slow, deep, relaxed breathing is a bottom-up approach – relaying messages from the body to the ANS’s lower (brainstem) and higher (cerebral cortex and limbic system) control centers, promoting relaxation and reducing reactivity. Combining mindfulness with slow, deep, relaxed breathing leads to a calm state, thanks to reduced sympathetic outflow and increased parasympathetic activity.
The Diaphragm and the Vagus Nerve
The function of the diaphragm is as vital to autonomic stability as it is to proper respiration. Diaphragmatic breathing, also known as belly breathing, involves slow, deep nasal inhalation, causing the diaphragm to expand downward. Full diaphragmatic movement causes the abdomen to rise with inhalation and fall with exhalation. The vagus nerve innervates and passes through the diaphragm alongside the esophagus. Due to this close proximity, diaphragmatic breathing stimulates, activates, and stabilizes the vagus nerve.
The vagus nerve’s significance to parasympathetic activity is immense. Also known as the tenth (X) cranial nerve, the vagus is the longest cranial nerve and contains 75% of all parasympathetic fibers. The vagus is a mixed nerve containing both sensory and motor fibers. Stimulation of the vagus at the level of the diaphragm conveys to organs both below and above the diaphragm and ANS control centers in the hypothalamus and brain stem. Integrative practices that include diaphragmatic breathing stimulate parasympathetic activity and improve autonomic stability.
Anyone who has experienced prolonged stress should be encouraged to develop a routine or practice that includes diaphragmatic breathing. Incorporating mindfulness helps reduce reactivity to stressful events and sympathetic stimulation. Owing to the nature of the prolonged stress response, be reassured that while recovery may take some time, you will see significant results with regular practice.
Slow Exhalation
In addition to diaphragmatic breathing, slowing and extending the exhale is a component of many integrative practices. Slow exhalation has a powerful effect on the PNS. Heart rate typically increases with inhalation and decreases with exhalation.
You can take advantage of the heart-rate-reducing effect of exhalation by extending the exhale portion of the breath. One of the most effective ways to slow exhalation is to use pursed-lip breathing. Individuals with obstructive lung disease such as asthma and COPD are often taught to use pursed-lip breathing to reduce shortness of breath.
Pursing the lips means puckering or pursing the lips together, such as when drinking through a straw. This maneuver creates a small amount of back pressure on the airways, which opposes the forces exerted on the lungs from the respiratory muscles. It keeps alveoli and airways open, allowing more air to be exhaled from the lungs. This technique should be limited to 3-5 breaths at a time to avoid exhaling too much carbon dioxide.
Nasal Inhalation
The nose acts as a filter for inspired air. Hairs in the nose filter inspired air, trapping tiny molecules such as dust and pollen. The mucous membranes of the nose warm and humidify inspired air, making air healthier for the lungs and helping maintain body temperature. Nasal inhalation takes full advantage of these important physiological functions.
Inhaling through the nose primarily stimulates the diaphragm, leading to diaphragmatic breathing. Breathing through the mouth stimulates accessory chest wall muscles, which is helpful during strenuous activity but not ideal for normal, quiet breathing.
A lesser-known benefit of nasal inhalation is the release of nitric oxide (NO). NO is a powerful and short-acting vasodilator produced in the paranasal sinuses, as well as other parts of the body. Nasal inhalation stimulates NO release into inspired air, which is then carried into the lungs. NO improves oxygenation, relaxes pulmonary blood vessels, has anti-microbial effects and reduces inflammation in the lungs. Humming has been found to increase NO levels 15-fold due to the increased oscillation of airflow in the sinus cavities. This supports claims that the Pranayama technique of Bhramari Pranayama, or ‘Bee’s Breath,’ reduces heart rate and enhances lung function and immunity.
Modern science is just beginning to study and quantify the nasal cycle (NC), a phenomenon long well-known to practitioners of Pranayama. This intrinsic cycle involves the alternating congestion and decongestion of the mucosa in the nasal passages. The pattern of congestion and decongestion may be side-to-side or parallel. This alternating pattern allows one side (or both) to filter and humidify while the other (or both) recovers. The length of time between phases is from 30 minutes to 6 hours.
Conclusion
Breathing is not just a life-and-death matter but also a quality-of-life matter. How you breathe affects many aspects of your well-being. It’s amazing and beautiful that simply pausing for a moment and taking one slow, deep breath can do so much for your body, mind, and soul.
(This is an abridged version of an article that first appeared in the June 2024 issue of Beginnings Magazine, a publication of the American Holistic Nurse’s Association. The original article is available as a CNE activity for nurses and can be accessed here.)