Post-exertional malaise and the myth of cardiac deconditioning: rethinking the pathophysiology of long covid, 2026, Charlton, Wüst et al

[V.R.T.]

Of course it's lost in all the 'stress' nonsense

So many important clues are I think, like whatever is going on that makes me get sick from watching intense TV shows now

 

[poetinsf]

I doubt this is the problem.

I was conveying what I was told: it siphons precious little energy they have for little result.

I'm not sure how one can conclude this without any data and patient reports being fairly mixed.

It takes very little to trigger PEM in severely ill cases (signal). And they still have to breathe, eat and go to bathroom (noise). Feel free to point me to the data if you have any, I'll be happy to change my mind.

I suspect it is much more as @InitialConditions describes with randomness and non-linear relationships making the whole thing more complicated then a simple cause and effect language implies.

That's just assumption without proof. We typically attribute what we don't understand to randomness as we do in statistics. There could be actual randomness, but we don't know that until we fully understand the process. And nobody put a serious effort to track and model it yet as far as I know.

if the brain is crucially involved things are likely going to be more complex than the opposite.

Not sure about that either. We know allergies have trigger threshold. So do migraine or PTSD. Some of them do involve brain.

edit: typo

 

[V.R.T.]

There could be some of that, but also decades of exercise studies have pretty much added up to the fact that it takes very little exercise to maintain a healthy body. Not fit, just healthy. Of course the recommendations vary wildly, based on which cherries get picked, but in recent years the shift has been noticeable, making this to be good news, that it pretty much only takes a little movement here and there during the day, that it's actually staying immobile for long periods of time that is the main concern.

Ironically, it could be that it's pacing that helps the most here, as pretty much all of us divide our activities in chunks during the day. I rarely sit down for more than 30 minutes at a time, my very repetitive days are a back-and-forth between sitting down, or taking a nap in late afternoon, and doing a bit here and there, including some light exercises and short walks, basically meeting most of the recommendations for light physical activity. Most people do, unless they are actively lazy, such as always avoiding stairs, always driving to the closest parking spot and just disliking walking or doing anything more exerting than getting up from the couch to grab a snack and back.

And when looking at exercise studies, the amount of exercise that is needed for a healthy level of fitness is also pretty low, anything above it will mainly increase markers of fitness, with little impact outside of showing visible muscle or being better able to compete physically. It's still pretty good to do regular exercise, but the benefits have been wildly exaggerated. The big tell is that people who work physically demanding jobs don't seem to do any better, if they did it would be promoted like a god appearing on toast. Instead, it's all about recreation, hence the shift in recent years from recreational exercise to recreational light activities.

Ironically, by promoting the lie that work is good for health (for most people, the thing they hate the most in their life is work, and the relationship is obviously backwards: being healthy makes it easier to work), the medical profession may have actually made things worse since most people work too much, sitting down for long hours without taking breaks. Plus if exercise were as good as falsely advertised, governments would have long have been subsidizing it to make it free. But not a single one does, because the math doesn't actually math here.

Yes I think a lot of media and health service messaging gaslights people into thinking they are unhealthy because they don't do intense exercise 4 times a week.

Looking back I was probably in better shape than your average office worker when mild, but was convinced I was 'unfit' - mostly because I felt dreadful all the time. And media tells us we feel bad because we're not hitting the gym or running 5k - it's always your fault.

It's frustrating to realise how much common wisdom about health and exercise is bullshit.

 

[InitialConditions]

I disagree. They can’t be listening if they still believe that an individually tailored rehab approach is suitable. Or that PEM is triggered by going past a certain cardiopulmonary threshold (or something of the like).

They are letting their own preconceptions dominate their work.

I think they are seeing things through the lens of exercise science, because most of them are exericse scientists. The focus on physical exercise and rehab is party, I think, because many still think PEM is just about exercise intolerance — this is something I tried to convey in my response.

So much of the functional impairment in ME/CFS/LC and PEM is only minimally related to physical activty/fitness, and I am not convinced that heart rate monitoring and ventilation threshold tracking can change that in most patients.

 

[rvallee]

This possibility was, of course, a bit of snark.

If it were true then we would be self-healing instantly all the time and hence would not be sick!

Actually this made me light up on the fact that the ideologues have always told us they don't even believe in the myth of deconditioning because they also keep saying that we can just get up and live normally if we want to. Most of them have some variation of Garner's story about fixing their fear of exercise, or whatever, in a few minutes and just going on a run and feeling fine for the first time. They would never say this about someone who they genuinely thought were deconditioned, such as recovering from a severe illness requiring hospitalization.

This means it was never about deconditioning, rather the myth was always truly about some imagined fear of... something. Fear of activity, of movement, whatever, doesn't matter. A ghost, unseen and immaterial, but able to influence reality.

What's especially frustrating is that this is the only context in which this shouldn't work, because facts and coherence should matter to professionals, and yet they clearly have no issue being extremely deceitful not just about what they say, but in excusing being deceitful. It's hard to overstate how important it is to force a change in making it illegal to lie, or even slightly deceive, in health care. This alone would simply kill psychosomatic ideology, which is likely the main reason it's a non-starter, even though it technically already is not allowed, but rules don't matter, only enforcement does.

 

[Mij]

Feeling better or worse randomly is often described as a "fluctuating illness". When I'm going through a 'good streak' I take advantage of it because I know it can reverse at any time for whatever reason.

I don't need anyone telling me how or coaching when to exercise.

 

[InitialConditions]

I don't need anyone telling me how or coaching when to exercise.

Yep. We are perfectly capable of reconditioning ourselves — if only our bodies would allow that.

 

[EndME]

It takes very little to trigger PEM in severely ill cases (signal). And they still have to breathe, eat and go to bathroom (noise). Feel free to point me to the data if you have any, I'll be happy to change my mind.

I'm not quite sure what you mean. I'm suggesting that there is no useful data to make firm conclusions, but at least people on S4ME seem to be saying that things appear more variable than a simple causal language might imply. Which is also what I've been told by clinican who sees ME/CFS patients, but who knows how to interpret that.

That's just assumption without proof. We typically attribute what we don't understand to randomness as we do in statistics. There could be actual randomness, but we don't know that until we fully understand the process. And nobody put a serious effort to track and model it yet as far as I know.

Indeed, that is why I said suspect. Apart from actual randomness one typically models things that are too complex to understand in any other way using probabilistic tools. It is completely unlikely that one ever fully understand all processes and it isn't necessary either. I'm biased but what I've heard from patients is that simple predictions don't seem possible more than perhaps an overall impression gives a somewhat valuable guideline. After all you will find various posts of people describing the difficulty to recognize PEM for numerous years. I suspect that things are roughly as @InitialConditions put it, but I don't know it or claim to have a proof.

Not sure about that either. We know allergies have trigger threshold. So do migraine or PTSD. Some of them do involve brain.

I'm not sure what you mean here. The models I've seen of migraines in humans, which in itself tend to be simplifications and probably useless characterisations, have lacked the simplicity you are talking about here. A friend whose been told to be suffering from pressure migraines cannot make any reasonable threshold predictions, so much as it is debated whether the condition exists in a straightforward manner because causal attibutions seem impossible.

Nobody is suggesting that anybody has to understand some awfully complex dynamics that may never be fully grasped. All that has to happen is to get a decent enough understanding of some overarching picture and being able to zoom in a few specifcs to make one useful prediction. I doubt anybody understands more than that about allergies, PTSD or the majority of medical conditions.

 

[EndME]

Perhaps an analogy:

I think healthy or at least regularly active people can typically predict whether or not they will get DOMS from an activity and they can almost always pinpoint which activity lead to DOMS. I think for PEM things look a bit less straightforward.

 

[Mij]

Also PVFS delayed fatigue/muscle exhaustion can also be unpredictable. I experienced that when I was recovering from Covid infection.

 

[Utsikt]

I think they are seeing things through the lens of exercise science, because most of them are exericse scientists. The focus on physical exercise and rehab is party, I think, because many still think PEM is just about exercise intolerance — this is something I tried to convey in my response.

Yes, but if they still think PEM is exercise intolerance, then they can’t be listening to the patients in any meaningful way. By listening I mean not just hearing the words, but making a good faith and neutral attempt at understanding what the patients are trying to convey to them. If they constantly reframe everything in terms of exercise, they are not listening any more than the BPS folks.

So much of the functional impairment in ME/CFS/LC and PEM is only minimally related to physical activty/fitness, and I am not convinced that heart rate monitoring and ventilation threshold tracking can change that in most patients.

I fully agree.

 

[Sean]

There could be actual randomness, but we don't know that until we fully understand the process.

This is probably correct. At least some of what we might currently perceive as random is just insufficient understanding of the causal relationships driving it all.

I don't need anyone telling me how or coaching when to exercise.

Yep. We are perfectly capable of reconditioning ourselves — if only our bodies would allow that.

This. In fact we do it naturally, without planning, or motivating by an external force.

 

[Medfeb]

Great points raised in the letter by @InitialConditions. I agree. But I'm also wondering if a small part of the issue is in what the authors mean by the term "rehabilitation" in this context?

I expect most of us think of rehab as approaches whose goal is to recover and/or improve performance, function, etc. This could presumably include self-management. Pacing clearly does not fit in that scope.

But could they be including in their definition, rehabilitation approaches whose goal is to stabilize? Are they trying to fit pacing into their toolkit of rehab approaches since rehab is what they do?

Not saying this would be a good thing as the medical community at large will be using the improvement narrative.