Lung Capacity – Voice Science

Definition

Lung capacity refers to the maximum volume of air the lungs can hold, typically 4–6 liters in healthy adults (larger in males, smaller in females). This total encompasses several subdivisions: Vital Capacity (VC)—the maximum air that can be voluntarily moved—Tidal Volume (TV)—normal breath volume—and Residual Volume (RV)—air remaining after full exhalation. For singing, breathing efficiency matters more than absolute capacity; trained singers do not have larger lungs than non-singers, but demonstrate superior coordination in utilizing available volume.

Context

Relevance to Voice Production

The respiratory system functions as the power source for voice production, generating and regulating subglottal pressure for phonation. Typical conversational speech requires approximately 800 Pa (~10 cmH₂O), while singing demands 5–40 cmH₂O depending on pitch and loudness (Bouhuys, Proctor, and Mead, 1966). This fundamental connection between respiratory support and phonation has driven over 175 years of scientific investigation.

The critical distinction between trained and untrained singers lies not in absolute lung size but in breathing coordination. Research consistently demonstrates that trained singers achieve equivalent or superior acoustic output with lower mean airflow rates—52 mL/s in trained male classical singers compared to 114 mL/s in untrained individuals (Salomoni, van den Hoorn, and Hodges, 2016). This efficiency, rather than capacity, distinguishes professional voice users.

Historical Development

John Hutchinson (1811–1861) established the scientific study of lung capacity in 1846, coining both “spirometer” and “vital capacity”—which he termed “the capacity for life.” He systematically collected measurements from 2,130 individuals, establishing the first normative respiratory data.

Konno and Mead (1967) established the two-compartment model of chest wall mechanics, providing the theoretical framework that enabled Thomas Hixon’s subsequent research on respiratory kinematics during speech and singing. The landmark Watson and Hixon (1985) study of opera singers became the foundational work establishing modern understanding of respiratory patterns in trained classical singers.

Scientific Basis

Volume Subdivisions

The American Thoracic Society and European Respiratory Society establish standardized definitions for lung volume measurements:

Measurement	Typical Adult Values	Description
Total Lung Capacity (TLC)	6 L (male), 4.2 L (female)	Volume at maximum inspiration
Vital Capacity (VC)	4.8–6.0 L (male), 3.2–4.5 L (female)	Maximum air that can be voluntarily moved
Functional Residual Capacity (FRC)	~3.0 L	Volume after passive exhalation
Tidal Volume (TV)	300–500 mL	Normal resting breath volume
Residual Volume (RV)	~1200 mL	Air remaining after maximum exhalation
Inspiratory Reserve Volume (IRV)	1900–3300 mL	Additional air beyond tidal inhalation
Expiratory Reserve Volume (ERV)	700–1200 mL	Additional air beyond tidal exhalation

Males demonstrate 20–30% higher lung volumes than females of equivalent height, with breathing patterns tending to be more costal in females and more abdominal in males. These differences correlate primarily with body size rather than sex per se.

Respiratory Mechanics for Singing

The Watson and Hixon (1985) study established that distinct respiratory compartments serve separate functional roles during singing: “The abdomen served as a posturing element that mechanically tuned the diaphragm and rib cage to optimal configurations for performance. The rib cage operated as a pressure-flow generating element that regulated expiratory drive. And, the diaphragm functioned as an inspiratory element devoted to reinflating the lungs.”

Notably, the same study found that “subjects’ descriptions of how they thought they breathed during singing bore little correspondence to how they actually breathed”—a finding with significant implications for pedagogy.

Professional classical singers initiate phrases at 70–100% of vital capacity and often extend to near residual volume at phrase termination, requiring inspiratory muscles to brake passive recoil forces during expiration (Thomasson and Sundberg, 1997). Dynamic MRI studies reveal that subglottal pressure regulation during pitch jumps involves sudden diaphragm contractions rather than rib cage adjustments, with posterior diaphragm movement approximately twice as large as anterior movement during sustained phonation (Traser et al., 2020).

Pedagogical Considerations

Genre and Context Variability

Optimal breathing strategy varies significantly by genre, phrase demands, and even moment-to-moment within a single song. No universal breathing technique applies across all singing contexts, and attempts to identify stereotypical patterns even within classical singing have been “inconclusive” due to subject-specific techniques (Salomoni, van den Hoorn, and Hodges, 2016). Singers adapt their respiratory coordination dynamically based on phrase length, dynamic requirements, register, and stylistic demands.

Classical singing requires fundamentally different breathing coordination than speech or untrained singing. Professional classical singers demonstrate pre-phonatory inward abdominal movements that elevate intra-abdominal pressure, increasing the pressure-generating capacity of rib cage expiratory muscles and optimizing respiratory efficiency. The appoggio technique involves maintaining expanded ribcage configuration while engaging abdominal muscles—though scientific studies reveal high inter-individual variability in how singers achieve this coordination.

Contemporary Commercial Music (CCM) requires different breath management. CCM phrases are typically shorter, and over-inhaling can create tension and resistance. Deep abdominal breathing that lowers the larynx—useful for classical tone—is often counterproductive for CCM styles where speech-like, higher laryngeal positioning is preferred. Professional country singers use similar lung volumes for speaking and singing (55–65% VC), in contrast to classical singers who use significantly higher volumes (Cleveland, 1994).

Belting demands precise coordination of respiratory drive and glottal resistance, requiring dynamic adjustments of breath pressures according to changing needs and in balance with glottal resistance efforts.

Observable Assessment Factors

Maximum Phonation Time (MPT) serves as the most accessible respiratory-related voice measure. An MPT shorter than 10–12 seconds may warrant clinical investigation. Conditions affecting respiratory-phonatory coordination include COPD, presbyphonia, Parkinson’s disease, and vocal fold paralysis.

Common Misconceptions

Misconception: “Singers have larger lungs than non-singers”

Reality: Multiple studies confirm that trained singers do not possess anatomically larger lungs than non-singers when corrected for body size. Heller, Hicks, and Root (1960) found “no differences between the two groups of subjects…which could not be explained upon the basis of age, size, or errors involved in making the measurements.” Schorr-Lesnick et al. (1985) compared singers, wind instrumentalists, and controls, finding no significant differences in FEV₁, FVC, MVV, or respiratory pressures between groups.

Misconception: “Increasing lung capacity will improve singing ability”

Reality: Breathing efficiency and coordination distinguish trained singers, not absolute lung volume. Gould and Okamura (1973) found that trained singers showed lower RV/TLC ratios that improved with training duration, concluding: “The increased singing ability of the trained professional singer arises in large part from the ability to increase breathing efficiency by reducing the residual lung volume.” Research on respiratory exercises found that “current evidence does not support using respiratory exercises for all patients with voice disorders” (Desjardins and Bonilha, 2020).

Misconception: “There is one correct way to breathe for singing”

Reality: Breathing strategies vary by genre, by individual, and even moment-to-moment within a single performance. Classical singers use fundamentally different patterns than CCM singers, and research shows higher variability among trained professionals than untrained controls “due to the development of subject-specific techniques” (Salomoni, van den Hoorn, and Hodges, 2016). Body type, repertoire demands, and stylistic goals all influence optimal respiratory coordination.

Related Terms

Also known as: Pulmonary capacity, Lung volumes 

See also: Vital Capacity (maximum air that can be voluntarily expelled), Subglottal Pressure (pressure below the glottis driving phonation)

References

Bouhuys, Arend, Donald F. Proctor, and Jere Mead. 1966. “Kinetic Aspects of Singing.” Journal of Applied Physiology 21(2): 483–496. https://doi.org/10.1152/jappl.1966.21.2.483.

Cleveland, Thomas F. 1994. “Respiratory Function during Speaking and Singing in Professional Country Singers.” Journal of Voice 8(3): 251–260. https://doi.org/10.1016/S0892-1997(96)80017-8. 

Desjardins, Mélanie, and Heather Shaw Bonilha. 2020. “The Impact of Respiratory Exercises on Voice Outcomes: A Systematic Review of the Literature.” Journal of Voice 34(4): 648.e1–648.e39. https://doi.org/10.1016/j.jvoice.2019.01.019. 

Gould, Wilbur J., and Hiromitsu Okamura. 1973. “Static Lung Volumes in Singers.” Annals of Otology, Rhinology & Laryngology 82(1): 89–95. https://doi.org/10.1177/000348947308200118. 

Heller, Samuel S., Wallace R. Hicks, and Walter S. Root. 1960. “Lung Volumes of Singers.” Journal of Applied Physiology 15(1): 40–42. https://doi.org/10.1152/jappl.1960.15.1.40. 

Salomoni, Sauro, Wolbert van den Hoorn, and Paul Hodges. 2016. “Breathing and Singing: Objective Characterization of Breathing Patterns in Classical Singers.” PLoS ONE 11(5): e0155084. https://doi.org/10.1371/journal.pone.0155084. 

Schorr-Lesnick, Barbara, Alvin S. Teirstein, Lawrence K. Brown, and Albert Miller. 1985. “Pulmonary Function in Singers and Wind-Instrument Players.” Chest 88(2): 201–205. https://doi.org/10.1378/chest.88.2.201. 

Thomasson, Margareta, and Johan Sundberg. 1997. “Lung Volume Levels in Professional Classical Singing.” Logopedics Phoniatrics Vocology 22(2): 61–70. https://doi.org/10.3109/14015439709075318. 

Traser, Louisa, Fabian Burk, Ali Caglar Özen, Michael Bock, Bernhard Richter, and Matthias Echternach. 2020. “Respiratory Kinematics and the Regulation of Subglottic Pressure for Phonation of Pitch Jumps—A Dynamic MRI Study.” PLoS ONE 15(12): e0244539. https://doi.org/10.1371/journal.pone.0244539. 

Watson, Peter J., and Thomas J. Hixon. 1985. “Respiratory Kinematics in Classical (Opera) Singers.” Journal of Speech and Hearing Research 28(1): 104–122. https://doi.org/10.1044/jshr.2801.104.