I would certainly like to see the reference for a study showing 2 day CPET results similar to ME/CFS in deliberately bed-rested normals. That would be important.
Dear Professor Edwards, there isn't an exact replication study of "2 day CPET" per se, since that exact protocol is a new idea, Pacific Labs?. However, there is a body of literature on inflammatory markers 24h post-exercise in bed-rested subjects, both human and animal. These studies show convincingly that bed rest results in an inflammatory cascade, and fall in peak VO2, not otherwise seen in sedentary controls or normal subjects. Since the claim from Pacific Labs is a potentially important one, I don't think their conclusions are sound until deliberately bed rested healthy controls are tested accordingly.
We also have to be very careful about the use of the term "VO2max". True VO2max is not easily achieved on exercise stress testing (even in healthy subjects) and often a surrogate term, "peak VO2 achieved" is substituted and the terms used interchangably. These are not the same measures at all. For example, if a person stopped exercising at a heart rate of 60% maximum for reasons of percieved effort, that would result is a dismal peak VO2 achieved, but that is not the actual physiological VO2max.
Please examine the data from CFS exercising stress testing, in some of these studies 0% of subjects were willing/able to exercise to 85% maximum heart rate, some subjects achieving only 120bpm. Thus, as per the NY association of cardiologists guidelines, these exercise stress tests should be void. Again, I fear CFS specialists are blurring the lines here between a real physiological measure (VO2max), a completely different term (peak VO2) and a known phenomenom of cytokines and inflammatory markers that are seen in bed rested otherwise healthy controls.
Let us also think logically about this for a moment, on the PACE trial the patients could only walk 300 metres in 6 minutes (1.8mph), yet on VO2max exercise stress testing one has to achieve at least 3.2mph at 6 minutes to reach a valid VO2max. And we also know from other CPET trials on CFS patients that they reach stage 5 and 14minutes on average - 4.2mph. So either those PACE trial patients were pretending to walk slowly, or the patients able to reach VO2max on CPET are completely different patients. Again, this whole area is a mess and I really have no confidence in any of the findings.
To @
chipmunk1 above, we all know there are different claimed incidences for this disease - Reeves claims 2-3%, Crawley UK claims 4.7%, Wessely/White claim 1-2%, Jason et al (CCC) claim a tenth of that 0.1-0.2%. Dr Esther Crawley further published data showing that 90% of her subjects recovered with nothing more than advice.
Can't you see that your argument is circular, either the Canadian Guidelines are right, in which case 90% of those diagnosed with ME/CFS are making recoveries from false-belief, or they are wrong, and nothing you have said makes any sense whatsoever.
What I have merely added to the above equation is that now the false-believers know what the Canadian Guidelines require, many of those people are becoming mixed in too, the CCC have therefore been rendered next to useless.
- The patient knows what is required to get a diagnosis of ME/CFS
- When asked "do you have post exertional malaise on the silly check box diagnosis scheme, the patient merely says to the "CFS specialist - yes doctor I do.
This is the reality of CFS diagnosis today.