Respiratory volumes
You need to learn the definitions and typical values.
Tidal volume (TV) – the volume of air inspired or expired in one breath
Frequency (F) – the number of breaths per minute
Minute ventilation (VE) – the volume of air inspired or expired in one minute
VE = TV x F
You need to know typical values at rest and during exercise.
At rest
TV = 500ml (0.5L)
F =12 – 15 breaths per minute
VE = 6 – 7.5 L/min
During exercise
TV = up to 3 – 4L
F = increases to max 40 – 60 breaths per minute.
VE = Max 120 – 180l/min - dependant on size and aerobic fitness.
Remember that during max intensity (anaerobic) activity F increases to a max
value although the depth of breathing (TV) may be lower than higher level
aerobic activity. This is due to the internal intercostals contracting to speed up
breathing (see mechanics of breathing).