Lesson 4: Measuring Lung Function in Spirometry

The function of lungs can be measured using a spirometer.

Tidal volume

  • A spirometer can measure the tidal volume in lungs.
  • The tidal volume is the volume of air in a normal breath at rest.
  • A typical tidal volume is about 0.4-0.5dm³.

Ventilation rate

  • Spirometers can also measure the ventilation rate.
  • The ventilation rate is the number of breaths someone can take per minute (when at rest).
  • The average ventilation rate is around 15 breaths per minute.

Vital capacity

  • A spirometer can measure vital capacity.
  • The vital capacity is the maximum volume of air that can be breathed in or out of the lungs.
  • It is essentially the lung capacity.

We've learnt about 3 things a spirometer can measure. Lets consolidate this knowledge before learning about a few more things a spirometer can measure.