Tidal volume (symbol VT or TV) is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young human adult, tidal volume is approximately 500 mL per inspiration or 7 mL/kg of body mass.
Tidal volume is the volume of air you breathe in a single breath. Exercise causes an increase in tidal volume because your requirements for oxygen go up. This increase is mediated in different ways depending on when it occurs during your exercise. An increase in tidal volume is necessary to effectively meet your body's increased oxygen requirements, as an increase in your rate of respiration alone is not sufficient.
Why does tidal volume increase exercise?
Pulmonary ventilation increases because of a rise in tidal volume and respiratory rate to meet increased oxygen demands. Oxygen delivery during strenuous exercise is limited by cardiovascular function.