There was a gotcha in this paper, that, so far, seems to have escaped the critics on this forum. It concerns the "sub-anaerobic exercise test" (SATET).
The SATET is based on normative data from healthy populations and was performed on an exercise cycle, with participants maintaining a wattage of 90% of their predicted work rate.
There is actually no indication of awareness that either CFS or MS patients just might have a lower anaerobic threshold for exercise. The inherent safety of the test was already proved because other researchers had used it. (Wait a minute! What are we actually testing here?) I can't find any good explanation for why about 1/3 of their patients failed to complete the initial test. (Obviously, such people are to be disregarded.)
I would also point out a fundamental contradiction in experimental design. There were using an (assumed) aerobic exercise challenge, but made no attempt to measure aerobic capacity afterward. The question of whether or not those patients who were able to complete the test gained or lost capacity for aerobic exercise simply was not addressed. The two tests of function required only the ability to stand quickly without assistance (TUG) and walk 25 feet (T25FW). Neither of these requires aerobic exercise; you could hold your breath and might even do better on the times, like a sprinter. How this translates into maintaining daily function is unclear. If you can make it out of the laboratory the researchers' job is done.
Several inferences take us from studies of the healthy population to these patient population. More inferences take us to a conclusion regarding subjective measures like rating of perceived exertion (RPE). It appears that both MS patients and CFS patients have something wrong with their
perception, not physiology:
Thus the results imply that those with MS and CFS perceive their effort during exercise differently from a healthy population.
There is even an internal contradiction in the logic. Patients have a problem with perceived exertion which doctors can't measure. Overexertion may cause relapse. How are patients to limit exercise safely if they can't tell when they are approaching limits?
Lets go back to consider those patients who were unable to maintain the required heart rate for 90% of predicted work rate (power output). How did researchers get those predictions? They used a crude rule of thumb for the healthy population, HR = 220 - age. Never mind that both groups of patients suddenly began to behave like people many years older at disease onset. The idea that these patients had problems maintaining exercise, and reported higher levels of perceived exertion because anaerobic thresholds were in fact different in illness, was simply ignored. ("It is so much simpler to compute 220 - age.") There is simply no awareness that those who could not complete the test as prescribed just might have lower thresholds than healthy people.
So, how do they know the exercise challenge was actually sub-anaerobic? It was labeled as such, and other researchers were of the same opinion.
("See, it says sub-anaerobic right on the box, and prominent doctors endorse it on TV.")
My opinion of this work is so negative that I have to ask others here to check that I have not allowed emotion to carry me beyond facts stated in the paper.
I confess that I am already imagining new publications with titles like "Demyelination as a Consequence of False Illness Beliefs".
but I know there are some stats whizzes on here.
