VO2 Max
A multipart rate used to measure the maximum rate of oxygen by a person during maximal exercise.
The term“VO2 max” is derived from three abbreviations:
- “V” for volume,
- “O2” for oxygen, and
- “max” for maximum.
It is used to test fitness in athletes, but also in a healthcare setting, to assess patient’s cardiovascular function etc.
Measuring VO2 Max
For athletes, measuring their VO2 max is a fun experience.
They strap a mask on your mouth and nose, one hooked to a machine measuring your breathing.
Then, they stick you on a treadmill, and keep upping the speed until you cannot keep up—the point of physical collapse, basically.
(They don’t go so hard on hospital patients, for obvious reasons.)
VO2 max is a multipart rate, with three completely different terms:
- milliliters (mL) of oxygen consumed per
- kilograms (kg) of body weight per
- minutes (min) of time.
VO2 max is the peak rate of oxygen use, so it’s measured over a short window at the end of the test, not averaged over the whole test.
If, in the final 30 seconds before exhaustion, 2,250 mL of oxygen were consumed by an athlete (who weighed 80 kg), we can record the following multipart rate: 2,250 mL / 80 kg / 0.5 min
Using the “rational number and grouped units” format, we write the multipart rate as: = 2,250 ÷ 80 ÷ 0.5 mL/kg/min = 28.125 ÷ 0.5 mL/kg/min = 56.25 mL/kg/min to give a result in terms of unit values.
