How might an exercise physiologist use such a probe to do his or her work with athletes?

My Biology teacher put this question on my lab about Cellular Respiration but I need help answering it. The questions reads:





"The amount of CO2 in the air can be measured using a CO2 probe. How might an exercise physiologist use such a probe to do his or her work with athletes?"|||by measuring the CO2 conc in his expiration in a polythene bag.


i guess!