Cambridge O Level Biology · Syllabus 5090 · Human Gas Exchange
Ventilation Rate
What is Ventilation Rate?
The total volume of air moved into and out of the lungs in a given time, usually one minute. It is calculated by multiplying the breathing rate, the number of breaths taken per minute, by the volume of air moved in a single breath. Ventilation rate is therefore a more complete measure of breathing than breathing rate alone, because two people can take the same number of breaths per minute while moving very different volumes of air. During physical activity both the rate and the depth of breathing increase, so the ventilation rate increases by more than the increase in rate alone would suggest.
This definition is part of the Human Gas Exchange chapter in Cambridge O Level Biology.
Questions students ask about Ventilation Rate
What is the difference between breathing rate and breathing depth?
Breathing rate is how many breaths are taken in a given time, usually breaths per minute. Breathing depth is the volume of air moved in a single breath. Multiplying the two gives the ventilation rate, the total volume of air moved per minute. Counting breaths measures rate only, and says nothing about depth.