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

[rvallee]

Again, where is the evidence for this in ME/CFS patients? It cannot be assumed, particularly for something that is clearly not responding to conventional ideas of rehabilitation (physical and psychological), and in fact carries a high level of serious risk with it.

Especially when we have written examples from some of the 'thought leaders' in the ideology who literally excuse their trials failing on the fact that the participants they chose themselves were plenty active already, IIRC it was a Knoop CBT trial. The goalposts don't just move constantly, they shift and morph to the point where what used to be goalposts can become excuses to fail, then back again. There is zero consistency or adherence to facts in the ideology.

Severe patients and worse are obviously deconditioned, but it's the least of their problems, and the rest of us are definitely unfit, but not the point where deconditioning matters much. The idea that being unfit is the cause of all those symptoms is ludicrous, to the point of being disqualifying as professionals.

 

[Grigor]

I'm unfortunately very disappointed by this paper. It feels like it tries to activate patients in situations where it should not. The gradual safe reconditioning approach is a train wreck waiting to happen.

Some of it may still be applicable to very mildly affected patients, but as someone with severe ME, their recommendations are completely out of the question.

I appreciate that they address the issue of deconditioning, but this paper introduces a whole set of new rehabilitation problems. Or rather, not new problems, issues I thought we had already moved beyond.

 

[Evergreen]

I started exercising again years later when I felt better, I had no cardiac issues/deconditioning and exercised like I was never sick, but this was when delayed PEM started and the delayed PEM symptoms gradually worsened over the years without my realising until it was too late.

You make a good point. Wüst & co might well not be very familiar with the relapse patterns in pwME/CFS. At one point I was - or thought I was - fully recovered. I had been doing moderate exercise without problems alongside full-time work and socialising normally. Returning tentatively and slowly to vigorous exercise seemed OK initially - crucially it did not bring on any symptoms/PEM - but within a few weeks of a certain (low) level of vigorous exercise, I relapsed and have never recovered.

Can this team honestly say that my and Mij's experiences would be reliably prevented by the approach outlined here? And how would they make sense of these relapses from apparently normal health back to ME/CFS, apparently triggered by exercise?

 

[Utsikt]

I read somewhere that roughly 50% of LC has the same (or very similar?) symptom profile as ME/CFS. Is that approximately accurate?

Not at all, unfortunately.

All of the estimates are based on either referrals to specialist clinics or online surveys. Those will have extreme sampling bias and are inappropriate for determining the rate of ME/CFS among LC patients.

EndME has also touched upon the fact that the ratios will be affected by how you define LC and ME/CFS. It will also be affected by when you measure.

 

[Eleanor]

You make a good point. Wüst & co might well not be very familiar with the relapse patterns in pwME/CFS. At one point I was - or thought I was - fully recovered. I had been doing moderate exercise without problems alongside full-time work and socialising normally. Returning tentatively and slowly to vigorous exercise seemed OK initially - crucially it did not bring on any symptoms/PEM - but within a few weeks of a certain (low) level of vigorous exercise, I relapsed and have never recovered.

Can this team honestly say that my and Mij's experiences would be reliably prevented by the approach outlined here? And how would they make sense of these relapses from apparently normal health back to ME/CFS, apparently triggered by exercise?

This reminds me of the study linked here https://www.s4me.info/threads/miscellaneous-research-thread.43053/page-2#post-673146

'Smartwatch-derived versus self-reported outcomes of physiological recovery after COVID-19, influenza, and group A streptococcus: a 2-year prospective cohort study'.

For all three diseases, we identified a gap between the time individuals reported symptom resolution and the time smartwatch data indicated their heart metrics had returned to baseline levels. Although individuals reported recovery, smartwatch measures of heart rate and HRV-based stress suggested they had not yet fully recovered from the infection. Heart rate values returned to baseline significantly later than HRV-based stress values, but both occurred after self-reported recovery. Additionally, when participants reported being symptom-free, their daily steps and sports activity returned to baseline levels, suggesting they might have been unaware of their incomplete recovery as they resumed their regular daily routines.

They're looking at recovery from acute infection, but it wouldn't be unexpected if the same thing held true for recovery from long-term illness.

 

[EndME]

I appreciate that they address the issue of deconditioning, but this paper introduces a whole set of new rehabilitation problems. Or rather, not new problems, issues I thought we had already moved beyond.

Indeed, I can appreciate that exercise scientists active in the ME/CFS and LC field have to say something about deconditioning even if it is just to appear as impartial or because of ones own ingrained training. However, this paper specifically addresses LC and ME/CFS rehabilition which historically is never about deconditioning but always about treatment. I'm not sure they are even talking about deconditiong because how are breathing exercises supposed to address that?

 

[Evergreen]

'Smartwatch-derived versus self-reported outcomes of physiological recovery after COVID-19, influenza, and group A streptococcus: a 2-year prospective cohort study'.

Nice.

It's theoretically possible that the "first ventilatory threshold-guided heart rate pacing" Charlton et al. recommend would have led to Mij and me being told "No, you're not ready. Stick to walking." But it's also possible that we would have looked absolutely dandy on that metric.

If they have gathered really good data from people with ME/CFS-LC being rehabbed, showing that VT1 is the dealbreaker between improvement and worsening during rehab, then I hope they will publish it. That would be a ground-breaking development. But I'm nervous that this is just another overreach without the data to back it up, which undermines their previous careful dismantling of the deconditioning dogma. If I've missed some important publications, please point me to them.

 

[Evergreen]

I'm not sure they are even talking about deconditiong because how are breathing exercises supposed to address that?

I wonder if the breathing exercises are targeting heart rate in pwPOTS?

Stratification of patients by POTS or PEM status allows for tailored rehabilitation plans, prioritising breathing exercises, low-intensity activities and pacing strategies for those experiencing PEM.

I don't have POTS, I have orthstatic hypotension, and I actually have to be careful not to do relaxing breathing when upright because it brings my blood pressure down.

 

[EndME]

I wonder if the breathing exercises are targeting heart rate in pwPOTS?

Quite possibly and I find it possible that breathing exercises also lower heart rate upon HUT or other scenarios but is there evidence to suggest that it does more than that?

 

[Felis Catus]

Nice.

It's theoretically possible that the "first ventilatory threshold-guided heart rate pacing" Charlton et al. recommend would have led to Mij and me being told "No, you're not ready. Stick to walking." But it's also possible that we would have looked absolutely dandy on that metric.

If they have gathered really good data from people with ME/CFS-LC being rehabbed, showing that VT1 is the dealbreaker between improvement and worsening during rehab, then I hope they will publish it. That would be a ground-breaking development. But I'm nervous that this is just another overreach without the data to back it up, which undermines their previous careful dismantling of the deconditioning dogma. If I've missed some important publications, please point me to them.

In the paper, they cite a pre-preprint Wearable heart rate variability monitoring identifies autonomic dysfunction and thresholds for post-exertional malaise in Long COVID co-authored by Wurst.

Conclusion Heart rate variability, assessed by wearables, confirms autonomic dysfunction in patients with long COVID. The delayed recovery of the sympathovagal balance after exercise close and above to VT1 suggests that VT1 can be practically interpreted as a PEM threshold.

Application These results confirm the applicability of wearables to assess autonomic function and manage overexertion in long COVID patients.

I haven't read the manuscript but this doesn't hold for cognitive exertion for those of us who don't experience increase in the HR during cognitive activity.

 

[Mij]

Can this team honestly say that my and Mij's experiences would be reliably prevented by the approach outlined here? And how would they make sense of these relapses from apparently normal health back to ME/CFS, apparently triggered by exercise

PEM can also be episodic or cumulative. After returning to work and feeling almost recovered, my brain wired-up and I could no longer shut it off or sleep after 10 days of working, slow staggering/swaying gait and unable to stand upright. I went for one run during that period and had odd sensations in my arm muscles. I was losing power over the next 10 days and had to resign from working.

 

[rvallee]

I'm not sure they are even talking about deconditiong because how are breathing exercises supposed to address that?

The hype seems to have mostly deflated but I have not seen any explanation beyond "well, respiratory problems mean you do respiratory rehabilitation, duh", which itself is not an explanation, just tortured logic. For the first few years there was a lot of hype and baseless assertions, it was fully assumed and asserted that it would do the trick, and like pretty much all rehabilitation, as far as I can tell, no one thinks beyond "you do x rehabilitation because then x is rehabilitated".

Honestly, as far as I can tell most of the rehabilitation evidence base consists of "this doesn't seem to work much, but we find no evidence that it makes anything worse so it probably works", and when you consider how PEM is pretty much completely ignored and all the harm that GET has wrought is dismissed, including when PEM is a major issue, I don't think any of that holds up either.

 

[SNT Gatchaman]

I cannot say it enough: I think patients are not deconditioned, or as deconditioned, as the standard deconditioning theory being invoked by rehab proponents would predict, and if that is correct then this apparently paradoxical phenomena is a very critical clue.

I would say I am nowhere near as deconditioned as I "ought to be". Some days my muscles are quite wobbly, on better days they are near normal for limited activity. In terms of cardiac deconditioning, just looking at my recent data, my HR still routinely reaches the mid 40s overnight. (Prior to illness it went to low 40s or even high 30s such that I had to turn off low HR notifications.) But if I had significant cardiac / cardiovascular deconditioning in the context of average ~1000 steps per day housebound (following bedbound) for 5 years now, I would have expected a much higher resting overnight HR. I think you'd expect to be >60 during sleep with any meaningful degree of cardiac deconditioning.

 

[V.R.T.]

I cannot say it enough: I think patients are not deconditioned, or as deconditioned, as the standard deconditioning theory being invoked by rehab proponents would predict, and if that is correct then this apparently paradoxical phenomena is a very critical clue.

This is a very good point- it would be so ironic if a vital clue was missed because doctors had been confidently stating it was all deconditioning when pwME for some reason don't become as deconditioned as they would br expected to.

 

[Felis Catus]

The hype seems to have mostly deflated but I have not seen any explanation beyond "well, respiratory problems mean you do respiratory rehabilitation, duh", which itself is not an explanation, just tortured logic. For the first few years there was a lot of hype and baseless assertions, it was fully assumed and asserted that it would do the trick, and like pretty much all rehabilitation, as far as I can tell, no one thinks beyond "you do x rehabilitation because then x is rehabilitated".

There has been a hype around "calming the nervous system" in LC by doing breathing exercises. Breathing exercises are supposed to improve autonomic function and increase HRV.

Putrino was involved in Meo Health (ex Stasis) programme which is a paid 12-week resonant breathing programme on a phone app. I couldn't be bothered to read their paper on symptom improvement following the programme.

 

[DHagen]

I think you'd expect to be >60 during sleep with any meaningful degree of cardiac deconditioning.

I did not realize that a "healthy" sleeping heart rate was that low - a quick search suggests that 40-60 is "normal." I don't think I am de-conditioned, but I may be in worse shape than I thought. Damn.

 

[V.R.T.]

This is a very good point- it would be so ironic if a vital clue was missed because doctors had been confidently stating it was all deconditioning when pwME for some reason don't become as deconditioned as they would br expected to.

My muscles feel extremely tense all the time, especially in PEM. I can't really relax them without effort. Like they are naturally just tense now. Could this have something to do with that?

 

[V.R.T.]

Putrino was involved in Meo Health (ex Stasis) programme which is a paid 12-week resonant breathing programme on a phone app. I couldn't be bothered to read their paper on symptom improvement following the programme.

I did stasis for 6+ months when I first became severe. Made no difference and I think the more intense exercises may have made my symtoms flare.

 

[Felis Catus]

I did stasis for 6+ months when I first became severe. Made no difference and I think the more intense exercises may have made my symtoms flare.

I'm severe and breathing exercises make me worse.

I did Stasis when I was moderate. No difference.

 

[V.R.T.]

I'm severe and breathing exercises make me worse.

I did Stasis when I was moderate. No difference.

I did them when I had first become severe and think about how intense some of the later exercises were and how they made me feel, and I wonder if I would have recovered more capacity if not for doing them.

Stasis were all over the long covid space in 2021. I did a group online session with them where the guy was telling people to sleep with tape over their mouth because breathing through your mouth in your sleep was bad for some reason...