[LisaS]

If you are thinking that you will be applying the detailed measurements from a lab in the gym you are likely mistaken.
I think you will find that the exam expects you to understand the formulas and apply them properly when given some lab values in a scenario type question like this:

Clinical problem 2 In the resting steady state, a well-trained jogger has an RQ of 0.8, end-tidal PCO₂ of 40 mm Hg, and a minute ventilation of 6 L/min. After 5 minutes on a treadmill at 2.5 mph, the following expired gas measurements are obtained: VCO₂ of 800 ml/min, VO₂ of 1000 ml/min, end-tidal PCO₂ of 39 mm Hg, and minute ventilation of 30 L/min. What are alveolar and arterial PCO₂ at this point?

You're not going to be doing any of that in a normal gym environment with a client.