Tidal Volume – Voice Science

Definition

Tidal volume (TV) is the volume of air moved during normal resting breathing—the amount inhaled and exhaled in a single quiet breath. Typical adult values range from 300–500 mL, approximately 6–8 mL per kilogram of body weight, representing roughly 10% of Vital Capacity. John Hutchinson originally termed this “breathing air” in his 1846 respiratory investigations.

Context

Relevance to Voice Production

Conversational speech occurs largely within or slightly beyond the tidal breathing range. Approximately 75% of chest wall volume change during speech happens below resting end-expiratory level (Hixon, Goldman, and Mead, 1976), meaning speakers typically exhale somewhat past their normal resting point but do not approach the extremes of their vital capacity. 

Singing, by contrast, often requires deliberate excursions well beyond tidal volume—classical singers initiate phrases at 70–100% of vital capacity, far above tidal range. Tidal volume itself can increase substantially during sustained phonation to meet the ventilatory demands of continuous vocal production.

Measurement

Tidal volume is easily measured via standard spirometry and serves as a baseline for calculating other volume relationships, including Inspiratory Reserve Volume (additional air above tidal inhalation) and Expiratory Reserve Volume (additional air below tidal exhalation).

Scientific Basis

Tidal volume represents the equilibrium point of quiet breathing, controlled by respiratory centers in the brainstem that automatically regulate breathing rate and depth based on blood oxygen and carbon dioxide levels. At rest, this automatic control produces consistent, rhythmic breathing within the tidal range. 

During physical exertion, emotional states, or singing, tidal volume increases as part of the body’s response to heightened metabolic or expressive demands. Sex differences in tidal volume are minimal when corrected for body size, as the measurement scales proportionally with body size.

Pedagogical Considerations

The distinction between tidal breathing and singing breath patterns has implications for voice training: 

• Speech breathing typically starts and ends near the tidal range, with breath groups terminating at approximately 30–40% of vital capacity
• Classical singing requires conscious expansion beyond tidal patterns, with phrase demands extending from near-total lung capacity to near-residual volume
• CCM styles often stay closer to speech-like tidal patterns than classical singing
• Over-breathing—taking in excessive volume beyond phrase requirements—can create tension, particularly problematic in styles where speech-like ease is preferred

Related Terms

Also known as: TV, Tidal Lung Capacity, Breathing air (historical) 

See also: Lung Capacity (parent concept), Vital Capacity (maximum voluntary volume), Functional Residual Capacity (volume at passive exhalation)

References

Hixon, Thomas J., Michael D. Goldman, and Jere Mead. 1976. “Dynamics of the Chest Wall during Speech Production: Function of the Thorax, Rib Cage, Diaphragm, and Abdomen.” Journal of Speech and Hearing Research 19(2): 297–356. https://doi.org/10.1044/jshr.1902.297. 

Kouri, Adamo, et al. 2021. “Exploring the 175-Year History of Spirometry and the Vital Lessons It Can Teach Us Today.” European Respiratory Review 30(162): 210081. https://doi.org/10.1183/16000617.0081-2021. 

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.