CPET

Question 1

Describe the V-slope method of assessing the anaerobic threshold from CPET results

Answer 1

Volume of CO2 exhaled during exercise is plotted against the volume of O2 used
The AT is the point where the slope of the relationship between VCO2 and VO2 becomes steeper than 1.0
The time when the rate of increase in VCO2 exceed the rate of increase of VO2

Question 2

How is the breathing reserve assessed and what is the implication of a lower than normal breathing reserve?

Answer 2

BR is the reserve capacity of the ventilatory system and is calculated as the difference between MVV and VEmax expressed as % of MVV and the normal values are between 20-30%.
An abnormal BR causes a ventilatory limitation to exercise

Question 3

Describe the normal change in VO2/change in WR trajectory and define abnormalities observed during a CPET

Answer 3

Continual linear rise throughout ET
Average slope calculated is 10 mL/min/W
Less than 8.4mL/min/W
Abnormal is VO2 converges to the guide line
CV disorders lead to a reduced trajectory especially above the AT due to an inadequate O2 supply and the higher contribution of anaerobic metabolism

Question 4

What does an abnormal O2 pulse progression during a CPET tell us about the possible cause of unexplained dyspnoea?

Answer 4

Amount of O2 consumed from the volume of blood delivered to tissues by each heartbeat
Early plateau suggests ischaemia
Indicates poorer than average CR function

Question 5

Define peak oxygen uptake

Answer 5

highest VO2 achieved

Question 6

Define maximal oxygen uptake

Answer 6

value achieved when VO2 remains stable despite a progressive increase in intensity

Question 7

Define anaerobic threshold

Answer 7

highest oxygen uptake attained without a sustained increase in BL concentration and lactate/pyruvate ratio

Question 8

Define RER

Answer 8

Ratio of VCO2 to VO2 shows acceptable level of effect from participant