Deconditioning does not explain orthostatic intolerance in ME/CFS, 2021, VanCampen, Rowe, Visser

cassava7 said:
Indeed, a comparison at the individual level would require having both pre-illness and current VO2max values. The former is not usually available, so the comparison is done with age and sex-matched reference groups:
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And, sadly, this is one area where few medical professionals have much in the way of skills.

Recently, in hospital, one doctor wanted me to start taking allendronic acid because I have been taking a low dose (10mg) of prednilosolone for a long time. I asked if he had read the studies on long-term low dose: he hadn't. I asked if he had looked at my previous DEXA scans, taken 10 years apart during the time I was taking the steroids. He hadn't.

I told him that on both occasions my spine was fine, and my hip was 1.4 standard deviations below the mean, which indicated no deterioration. He wanted to know what the T score was. It was 1.4, that's what the T score represents. But more than that, the T score uses data for younger, healthy individuals.

There were about eight doctors in the room at the time: none of them seemed to know much about it.

When I was discharged, guess what was in my package from the dispensary! Allendronic acid.

I know this is irrelevant to the discussion on deconditioning, but it keeps falling back to the perennial problem with our health system. It makes no effort to check us out when we are healthy, so has no primary data to compare our results or performance when we fall ill. Consequently assumptions are made about us based on group data, with a widespread ignorance of the implications of what such measures tell us.
 
Graham said:
I know this is irrelevant to the discussion on deconditioning, but it keeps falling back to the perennial problem with our health system. It makes no effort to check us out when we are healthy, so has no primary data to compare our results or performance when we fall ill. Consequently assumptions are made about us based on group data, with a widespread ignorance of the implications of what such measures tell us.
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Very much so. Systematic bias in datasets is a pervasive problem, and it is not one that is taught or emphasized enough even though it can, and often does, have serious real-world consequences.
 
Sadly, at school we used to teach a lot of "practical" maths, including the tricky art of interpreting statistical results, but the very traditional return to a tightly prescribed national curriculum cut this right back. It's true that at the time individual schools had too much freedom, and pupils moving from school to school were disadvantaged, but instead of creating a forward-looking curriculum, they resorted to the old grammar school ethos.

I think practical statistics ought to be part of a compulsory core of study for all sixth-formers, especially as it crops up in so many degree courses.
 
Graham said:
But surely VO2max is a measure of fitness: more specifically of endurance.

Deconditioning implies a change in an individual's level of fitness. Without a measure of what is normal for that individual, it is impossible to say if an individual is deconditioned.

Deconditioning also, as a term, implies no change in physical health. If one lung was removed, you could hardly expect the same level of fitness, and it would be ridiculous to put down any drop in fitness to deconditioning.

I can accept that astronauts could become deconditioned. I can't think of many other situations where the term could apply. A fit athlete could retire and become less fit – are they deconditioned?

The term just does not make sense to me.
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Yes @Graham good point - the term " deconditioning" implies a change - from what? I think I can safely guess that most people don't have a baseline of V02 max tested. So if V02 max is at least one important comparison, then they have no yardstick to refer to. It's doubtful the BPS Movement have tested pwME using this method. It's more in the purview of cardiologists, pulmonologists, kinesiologists and maybe physiotherapists.

And, since the BPS Movement's guidance is to do only basic testing, it's doubtful they are, or have been doing this level of testing on pwME. And even if they were, they don't have a baseline for each individual for comparison.

It appears that declaring a pwME is "deconditioned" is just a subjective call.
 
For many years, I did not understand ME and especially did not fully realise about PEM as we think of it now. I had young children and no help looking after them during the day as my husband was out at work and things like shops closed by the time he got home.

Now I know I was running on adrenaline and destroying my underlying health but at the time we just took it for granted that I wound rush around all day then be paralysed, blind and have to crawl up the stairs to bed then spend the weekend lying down.

In 1983 I walked from the house to the playgroup to the school to home with a half hour walk each way to the shops twice a week. Then home to playgroup to home to school to home to school. Lie down in the afternoon with toddler napping, then home to school to home often by way of the library. All done at a brisk pace and involving steep hills. I reckon I walked briskly for an hour and 10 minutes every day not counting the extra for shopping, brownies and cubs, library. Then there was the washing (not automatic) hanging it out making beds, tidying up. I collapsed after each chore then forced myself up again.

(I might have been able to get help but I was afraid my kids would be taken into care if anyone from outside realised how bad things were for me)

By no definition was I deconditioned so it astounded me when they suddenly started saying that deconditioning and fear of exercise caused ME.
 
Given that multiple 2-day CPET studies, including those from Visser and van den Campen, have found a reduction in the workload at ventilatory threshold on day 2, it would be interesting to know whether this value -- rather than peak VO2% -- relates to cerebral blood flow. This study selected participants who had done at least one CPET so not all of them may have undergone a 2-day CPET, but Visser and van den Campen would have the 2-day CPET data of those that have.
 
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