Is Breathing Important?

Breathing Is More Than Oxygen

Most people think of breathing in purely respiratory terms — the exchange of oxygen and carbon dioxide that sustains aerobic metabolism. This is, of course, the primary biological purpose of respiration. But breathing is simultaneously a mechanical, neurological, and psychological act with consequences that extend far beyond the lungs and into every domain of musculoskeletal health, pain processing, and nervous system regulation. We breathe approximately 20,000 times per day. If the mechanics of those 20,000 breaths are optimal — if the diaphragm descends appropriately, the thorax expands three-dimensionally, intra-abdominal pressure is managed correctly, and the accessory cervical and shoulder musculature remains appropriately quiet — the respiratory system supports spinal stability, reduces loading on the neck and shoulders, facilitates lymphatic and venous return, and maintains the autonomic nervous system in a balanced, adaptable state.

If those 20,000 daily breaths are mechanically dysfunctional — shallow, apical, predominantly driven by accessory respiratory muscles, with inadequate diaphragmatic descent and poor intra-abdominal pressure regulation — the cumulative mechanical and neurophysiological consequences are substantial. Chronic neck and shoulder pain, thoracic stiffness, chronic low back pain, pelvic floor dysfunction, and heightened pain sensitivity can all have dysfunctional breathing as a significant contributing factor. It is among the most underassessed variables in musculoskeletal practice.

The Mechanics of Optimal Breathing

Optimal breathing begins with the diaphragm — the dome-shaped musculofascial partition separating the thoracic and abdominal cavities, and the primary muscle of inspiration. During a well-executed breath, the diaphragm contracts and descends, increasing the volume of the thoracic cavity and creating a pressure differential that draws air into the lungs. Simultaneously, the descending diaphragm increases intra-abdominal pressure, managed by a coordinated cylindrical co-contraction of the diaphragm (above), the pelvic floor (below), the transversus abdominis (anterolaterally), and the deep spinal extensors (posteriorly) — the structure referred to in rehabilitation science as the deep stabilising cylinder.

This three-dimensional expansion — anteriorly, laterally, and posteriorly — is the hallmark of diaphragmatic breathing. The lower ribs flare gently outward with each inhalation; the abdomen expands forward and laterally; the posterior thorax broadens. The upper chest, cervical accessory muscles (scalenes, sternocleidomastoid), and shoulder girdle musculature remain largely uninvolved. Exhalation in quiet breathing is predominantly passive — driven by the elastic recoil of the lungs and thoracic cage as the diaphragm relaxes and ascends.

The Diaphragm and Spinal Stability

One of the most clinically significant discoveries in respiratory biomechanics research is the dual role of the diaphragm as both the primary breathing muscle and a critical contributor to spinal stability. Hodges and Gandevia (2000) demonstrated that the diaphragm co-contracts with the transversus abdominis in anticipation of limb movement — its postural stabilising function precedes and accompanies voluntary movement as part of the deep stabilising system, independent of its respiratory role. Kolar et al. (2012) provided compelling evidence that individuals with chronic low back pain demonstrate significantly altered diaphragmatic function: reduced intra-abdominal pressure generation during postural loading tasks, asymmetrical diaphragm position and descent, and impaired coordination between respiratory and postural activation of the deep cylinder. These findings implicate diaphragmatic dysfunction not merely as a coexisting feature of back pain but as a potential mechanistic contributor — a failure of the stabilising system that increases spinal loading and vulnerability during daily activity and exercise.

Dysfunctional Breathing Patterns

Dysfunctional breathing (DB) encompasses a range of altered breathing patterns that, while meeting baseline respiratory demands, impose progressive mechanical and neurophysiological costs. Upper chest (apical) breathing is characterised by predominantly upper thoracic and clavicular expansion with minimal diaphragmatic descent, chronically overloading the scalenes, sternocleidomastoid, and upper trapezius — contributing to forward head posture, upper cervical compression, and the trigger-point-dense upper trapezius and levator scapulae presentations that constitute a significant proportion of musculoskeletal clinic presentations. Mouth breathing bypasses the nasal cavity's filtering, humidifying, and nitric oxide-generating functions, producing drier, less conditioned air and reducing the nasal airway resistance that normally promotes diaphragmatic effort. Chronic hyperventilation — breathing at a rate or depth exceeding metabolic demands — reduces arterial CO₂ below optimal levels (hypocapnia). Since CO₂ is the primary stimulus for peripheral vasodilation and the facilitator of oxygen release from haemoglobin (the Bohr effect), chronic hyperventilation paradoxically reduces oxygen delivery to peripheral tissues despite increased respiratory effort, and sensitises the nervous system through its effects on neuronal excitability.

The Breathing-Pain Connection

The relationship between dysfunctional breathing and musculoskeletal pain operates through multiple converging pathways. Direct mechanical loading: Chronic upper chest breathing imposes sustained overload on the cervical and upper thoracic musculature. At 20,000 breaths per day, even minor inefficiencies generate cumulative mechanical stress that maintains trigger points and perpetuates myofascial pain — and limits the effectiveness of manual therapy directed at the cervical spine and shoulder girdle if the breathing dysfunction driving the loading is not simultaneously addressed. Thoracic mobility: Optimal breathing requires a mobile, three-dimensionally expandable thorax. Thoracic stiffness — ubiquitous in sedentary adults and those with chronic thoracic pain — both results from and further perpetuates dysfunctional breathing, diminishing shoulder range of motion, increasing cervical loading, and reducing the mechanical efficiency of the diaphragm's descent. Nervous system sensitisation: The hypocapnia produced by chronic overbreathing lowers the threshold for neuronal activation across the entire nervous system, including the nociceptive system — contributing to widespread, non-specific pain sensitivity that does not clearly localise to a single anatomical structure and responds poorly to tissue-directed treatment alone.

Breathing and the Nervous System

Breathing is one of the very few bodily functions governed simultaneously by both voluntary (somatic) and involuntary (autonomic) nervous system control — and this dual governance makes it uniquely accessible as a tool for directly influencing autonomic nervous system state. The work of Stephen Porges on polyvagal theory has illuminated the intimate relationship between respiratory patterns and the balance between sympathetic (fight/flight) and parasympathetic (rest-digest-repair) nervous system dominance. Slow, diaphragmatic breathing — characterised by a longer exhalation than inhalation — activates the high-road myelinated vagal pathways that support parasympathetic dominance: reduced heart rate, increased heart rate variability, reduced cortisol, and a shift in neural state toward the "safe, connected, capable of recovery" end of the autonomic spectrum.

For clients managing chronic pain — whose nervous systems are characteristically shifted toward sympathetic dominance and central sensitisation — the clinical implications are direct and practical. A diaphragmatic breathing practice is not a soft-skill adjunct to "real" treatment; it is a neurophysiologically active intervention that directly modulates the same pain-amplifying central nervous system mechanisms that manual therapy and pain neuroscience education address from different directions. Used together, these approaches compound their effects.

Assessing and Retraining Breathing

Clinical assessment of breathing begins with observation: watching the pattern of thoracic expansion during quiet breathing at rest, noting whether the upper chest leads the movement or whether the lower ribs and abdomen expand first, observing resting breathing rate (normal is 10–14 breaths per minute; rates consistently above 16 suggest overbreathing), and assessing for visible signs of accessory muscle dominance such as shoulder elevation with inhalation, forward head posture, and restricted lateral rib expansion.

Breathing retraining follows a progressive sequence: establishing diaphragmatic mechanics in supine with minimal loading, progressing to seated, then standing, then incorporating breathing coordination into movement and exercise. Nasal breathing should be established as the resting and low-intensity exercise default. Specific attention is given to slowing expiratory flow and re-establishing a natural, unconstricted respiratory rhythm. Breathing retraining requires consistent daily practice — typically 10–15 minutes of dedicated practice and progressive integration into movement and daily activity. Meaningful changes in resting breathing mechanics and autonomic nervous system tone are typically apparent within two to four weeks of consistent practice, with continued improvement over three to six months. For clients with chronic pain, postural dysfunction, or stress-related presentations, it is rarely time wasted.