The goal of the test protocol is to incrementally challenge energy production such that the patient is able to complete at least 8 min but no more than 12 min of cycling (
45). For
moderately ill ME/CFS patients who complete this protocol, workload increments of 10–15 W/min, beginning at 0 watts, is appropriate to achieve
an 8–12 min test to maximum effort duration. However, for a patient with a significant history of physical training, a 20 or 25 W/min protocol may be appropriate.
The same protocol should be used for CPET1 and CPET2.
[...]
Test termination should comply with testing guidelines (
45) and
is indicated by attainment of maximal effort, or test termination due to patient safety. When testing for evidence of disability, insurers and independent medical examiners will closely scrutinize patient effort. Therefore,
criteria for maximal effort should be reported which could include; plateau in oxygen consumption with increases in workload, RPE ≥ 18 (6–20 scale), respiratory exchange ratio (RER) ≥ 1.1, or peak blood lactate ≥ 8 mM. These criteria support evidence of maximum effort during CPET. The RER criterion is generally considered a more valid indicator of patient effort compared to the other indicators (
55). Generally,
satisfying two of three criteria is acceptable to determine that maximum effort was given by the patient (
56).
