Post-Exertional Malaise - a discussion including defining and measuring PEM

[Midnattsol]

I haven't taken a CPET, but during my years of illness I've had periods where I've been able to increase my physical activity and increase my fitness (up until a certain point, at which I would get PEM, no matter what I did to increase over this limit it just didn't happen. But in my last long remission that limit was above a few hours of mountain hiking and biking each week, with some strength training/power yoga as well). I'm sure a CPET at that time and one now would be different, although I'm not at my worst atm.

I felt healthy in that remission as it took so much for me to get into PEM that it really didn't bother me in my day-to-day life. I could spend 10 hours at university on a whim reading for an exam with others, I could join spontaneous hikes, I could spontaneously decide that I wanted to climb two mountains that day instead of one because the weather was nice and it felt so good being outside. I was active in student organizations. If I wasn't such an active person I don't think I'd have noticed I could get into PEM at all, as it really took a lot (over days) for it to occur. And it would pass quickly, at most reducing my functioning about two weeks and I'd be back to "normal".

When I did eventually crash it was after weeks/months of hard physical activity and little rest due to other circumstances. By the time I realised I wasn't recovering from my workouts it was too late, but I'm not sure it would have mattered. I was perhaps already deterioating by that point. Spent the next year more or less housebound with the occasional trip to university.

 

[Hoopoe]

The patient community may have attributed too much importance to the 2-day CPET for several reasons:

Most of us are not experts and so we're less aware of the limitations of research.
We want to see progress in research.
We want to fight back against disbelief with objective tests.
The 2-day CPET seems closely related to the important phenomenon of PEM.

 

[Invisible Woman]

The 2-day CPET seems closely related to the important phenomenon of PEM.

This is very much how I see it. It is closely related but we still don't really know or understand what's going on.

Also, for all we know PEM is like an iceberg in that the symptoms we observe may just be the tip & even if we seem symptom free it doesn't mean trouble isn't brewing underneath.

We just don't know enough about PEM and it may seem reassuring to cling to something measurable. If that measurable event is far downstream from the triggering event or changes then it may not be as reliable as we think.

 

[Medfeb]

The patient community may have attributed too much importance to the 2-day CPET for several reasons:

Most of us are not experts and so we're less aware of the limitations of research.
We want to see progress in research.
We want to fight back against disbelief with objective tests.
The 2-day CPET seems closely related to the important phenomenon of PEM.

I'd add that in the US at least, the 2-day CPET with its second day decrement is accepted in disability cases (including those decided by a court) of objective evidence of functional impairment and also the inability to work consistently 8 hours a day, 5 days a week. In one decision I saw, the judge explicitly cited the 2-day CPET report as the basis for his granting disability benefits

CPET results at day 2 may have some indirect relation to PEM but they do not provide any sort of direct explanation. The reason for saying that is that people with PEM feel awful regardless of whether or not they try to exercise. PEM is something that is there at rest, not just on repeat exercise. So whatever the CPET is measuring it is not the cause of the symptom, which was there prior to exertion.

@Jonathan Edwards - I think I'm missing something in this... I agree that people with ME have impaired functioning and have numerous symptoms that make them feel awful even if they have not exerted. But PEM as I understand the definition is the further reduction in functioning and exacerbation in symptoms that occurs when one exerts in any way - and not physical exercise. I appreciate that some may be so ill and so susceptible to PEM that any exertion can trigger it - eating, showering, speaking, thinking, etc. But that's still exertion. So what does it mean to say "PEM is there at rest?" What am I missing?

 

[Midnattsol]

I think of PEM as a cummulative thing. Or, I think of my ME mostly as a problem with recovering from anything.

It can take days to recover from exertion, and depending on what I'm recovering from and how much energy I spent any extra exertion (like eating) just can't be dealt with properly and may in worse case lead to more symptoms.

 

[Invisible Woman]

I'd add that in the US at least, the 2-day CPET with its second day decrement is accepted in disability cases (including those decided by a court) of objective evidence of functional impairment and also the inability to work consistently 8 hours a day, 5 days a week. In one decision I saw, the judge explicitly cited the 2-day CPET report as the basis for his granting disability benefits

On the one hand that's great but on the other -

People may be too ill to do the CPET in the first place - I would be concerned that the CPET might become a requirement.

People might do the CPET, have abnormalities recorded but it could be enough to tip them into further prolonged ill health unnecessarily.

Do we know that everyone with ME would have abnormalities recorded on the second CPET?

I'm not saying it doesn't have it's uses but it concerns me that it might be relied upon too much.

 

[Medfeb]

On the one hand that's great but on the other -

People may be too ill to do the CPET in the first place - I would be concerned that the CPET might become a requirement.

People might do the CPET, have abnormalities recorded but it could be enough to tip them into further prolonged ill health unnecessarily.

Do we know that everyone with ME would have abnormalities recorded on the second CPET?

I'm not saying it doesn't have it's uses but it concerns me that it might be relied upon too much.

Just to clarify - CPET is not a requirement for a positive disability decision and patients who are very ill likely have a level of functional impairment that can not be disputed by disability benefit providers.

But less severely ill patients who might have otherwise been rejected by disability benefits providers, have used it in successful disability claims. In the case I mentioned, without it, the patient would have been refused and left with not only no monthly stipend but also no health insurance unless they paid more than $1000/month for a private insurance policy.

Before any patient decides to undertake a CPET or any other method used to show functional impairment, they need to understand the risks versus the benefits

 

[Medfeb]

I think of PEM as a cummulative thing. Or, I think of my ME mostly as a problem with recovering from anything.

It can take days to recover from exertion, and depending on what I'm recovering from and how much energy I spent any extra exertion (like eating) just can't be dealt with properly and may in worse case lead to more symptoms.

Thanks for this. So is this saying that a patient can be in a constant state of PEM from previous overexertion combined with current exertion/overexertion?

 

[rvallee]

I think of PEM as a cummulative thing. Or, I think of my ME mostly as a problem with recovering from anything.

It can take days to recover from exertion, and depending on what I'm recovering from and how much energy I spent any extra exertion (like eating) just can't be dealt with properly and may in worse case lead to more symptoms.

Important. Any pwME doing a CPET would likely prepare for days, likely weeks, with excessive rest. Which skews things, but then it's the only way to actually be able to do the test. For a healthy person it's not even worth thinking about, it's done and gone in a few minutes. Such things are rarely taken into account, but even the sum of small exertions can bring about PEM just as well.

 

[Mij]

@rvallee I don't think excessive rest before the test would skew things. The pathophysiology is there no matter how much we rest. I can rest for 3 months, but PEM will set in as soon as I go over my energy window Rest does not alleviate PEM either, time does.

 

[Invisible Woman]

Just to clarify - CPET is not a requirement for a positive disability decision and patients who are very ill likely have a level of functional impairment that can not be disputed by disability benefit providers.

But less severely ill patients who might have otherwise been rejected by disability benefits providers, have used it in successful disability claims. In the case I mentioned, without it, the patient would have been refused and left with not only no monthly stipend but also no health insurance unless they paid more than $1000/month for a private insurance policy.

Before any patient decides to undertake a CPET or any other method used to show functional impairment, they need to understand the risks versus the benefits

I understand that it isn't a current requirement in the US or here in the UK.

I can also completely understand why there are some who feel they might have no choice but to take the risk but undergo the CPET to increase the chance of getting disability - this is, in a way, forcing them to do a test they might otherwise choose not to take.

As for it only being suitable for those with less severe ME - that is very easily abused. If you can't prove you've got ME (with a biomarker for example) then how do you prove the level of severity you experience makes it dangerous for you? It's still a risk for those at the milder end - we have all heard from people who just thought they'd have a go at something, a one off activity that proved enough to make them much worse for an extended period. So we don't really know who might be harmed.

For research, or if it were indicative of a certain treatment being appropriate that would be one thing. If it becomes the norm to accessing financial support you should already be entitled to, that's troubling - no blame whatsoever on the patients that do it.

Here, in the UK, when it comes to GET for example I have had it suggested to me even though my specialist quite clearly states I have severe ME and NICE guidelines only make the recommendation for those with mild to moderate ME. Not only have I had to point out it isn't suitable for severe patients I had to back it up with something else - luckily for me Tom Kindlon's paper on Under Reporting of Harms did the trick.

It may well be there are differences between different countries. I know if patients in the UK failing at benefit tribunals because they haven't done GET. If we do, finally, ditch GET, I would hate to see it become the norm that people who haven't gone through a CPET would be refused.

CPET may be very helpful for research. The results of a CPET won't necessarily make any difference (as far as I'm aware in the UK) to treatment options. I don't think it's there or necessarily safe enough to be used as a diagnostic tool. I would hate to it to become a yoke around the necks of those seeking assistance.

 

[rvallee]

@rvallee I don't think excessive rest before the test would skew things. The pathophysiology is there no matter how much we rest. I can rest for 3 months, but PEM will set in as soon as I go over my energy window Rest does not alleviate PEM either, time does.

Oh I meant it skews the perception because people who aren't familiar with the topic don't know that in order to simply be able to do the test extensive rest is required. All they know about is the test, unaware that something this trivial can take weeks of preparation. Meanwhile healthy people can just plop unprepared and be out without a second thought.

Bit like some economic data over whether people can come up with, say, $500 for an emergency expense, with a subset who says yes because they saved up for weeks in anticipation. This is important information but it's completely lost in how it's reported.

 

[Midnattsol]

Thanks for this. So is this saying that a patient can be in a constant state of PEM from previous overexertion combined with current exertion/overexertion?

We don't recover as we're supposed to, but I'm not sure I would call it constant PEM. More that we have a threshold for activity and if a patient hasn't recovered from previous exertion, they require less activity to reach their threshold. If a patient continuously doesn't recover, eventually only small exertions will lead to PEM as very little is needed to cross the threshold (and yes, there are problems with using "threshold" with this fluctuating disease). A big exertion might push someone well into PEM if their body is still recovering from some previous exertion, but otherwise it could be within their limits.

"Exertion" is also a very loose term here, when I feel worn down any sort of input feels like exertion. I've compared trying to read with running at some points.. noise, talking, sharp lights, strong smells can all feel tiresome and make me more crashed if I am in PEM. Temperature change is another thing I'm very sensitive to.

Although, I do believe PEM starts before we feel the symptoms, and if a patient is in this state continuously, that might be a state of constant PEM?

Important. Any pwME doing a CPET would likely prepare for days, likely weeks, with excessive rest. Which skews things, but then it's the only way to actually be able to do the test. For a healthy person it's not even worth thinking about, it's done and gone in a few minutes. Such things are rarely taken into account, but even the sum of small exertions can bring about PEM just as well.

Yes. It's a bit frustrating that some doesn't seem to get this.

 

[Midnattsol]

@rvallee I don't think excessive rest before the test would skew things. The pathophysiology is there no matter how much we rest. I can rest for 3 months, but PEM will set in as soon as I go over my energy window Rest does not alleviate PEM either, time does.

Forgot this quote

I'm not sure if the pathophysiology would always be there. I've pulled car tires in the snow every day for weeks a winter two years ago and felt fine, until suddenly I did not recover any more. But for an extended period I did recover and was able to do this without a drop in my time. I do hope to be in remission like that again.

 

[Mij]

@Midnattsol

I hope you have another remission too! I have never had one, it doesn't matter how good I feel or how much rest, PEM is always there if I go over.

 

[Invisible Woman]

Forgot this quote

I'm not sure if the pathophysiology would always be there. I've pulled car tires in the snow every day for weeks a winter two years ago and felt fine, until suddenly I did not recover any more. But for an extended period I did recover and was able to do this without a drop in my time. I do hope to be in remission like that again.

Yep, I used to have the odd remission like that & I would eventually bob back to a certain level if function. Then due to circumstances beyond my control I pushed too far and that was that.

In hindsight I look at these remissions & I think it gave me a false sense of managing my condition and PEM quite well - though I didn't call it PEM or understand it in the same way I do today.

Pacing /trying to manage PEM too tightly without taking into account the underlying illness fluctuates can mean you don't leave enough resource should you push into PEM & deteriorate for some other reason.

I would love to tease out if PEM is the same as, or a symptom of the fluctuations of the disease, or an different phenomenon.

Does severity (& I mean the fluctuating day-day kind as well as classification kind) cause PEM or does PEM cause the deterioration/severity?

 

[Medfeb]

I would love to tease out if PEM is the same as, or a symptom of the fluctuations of the disease, or an different phenomenon.

I'd think the fact that PEM can be triggered with a challenge, such as CPET or the other exertion methods used in ME research, means its not just a reflection of the fluctuation of the disease but rather a symptom of it.

 

[Invisible Woman]

I'd think the fact that PEM can be triggered with a challenge, such as CPET or the other exertion methods used in ME research, means its not just a reflection of the fluctuation of the disease but rather a symptom of it.

Agreed.

But I see it as a chicken and egg situation when it comes to severity - which is the cause - constant PEM defining the level of severity or the level of severity lowering the threshold so as to cause constant PEM.

The disease fluctuates, PEM thresholds fluctuate, one can be more severe yet stay within a lowered PEM threshold, one can be more mildly affected yet constantly triggering PEM.

Connected but not the same? Is one the driver of the other and if so which way round?

 

[Tom Kindlon]

Here, in the UK, when it comes to GET for example I have had it suggested to me even though my specialist quite clearly states I have severe ME and NICE guidelines only make the recommendation for those with mild to moderate ME. Not only have I had to point out it isn't suitable for severe patients I had to back it up with something else - luckily for me Tom Kindlon's paper on Under Reporting of Harms did the trick.

Nice to hear. That paper took a lot of work.

Anyone who wants to read, it's available here:
https://www.iacfsme.org/assets/Reporting-of-Harms-Associated-with-GET-and-CBT-in-ME-CFS.pdf

 

[Mij]

Moved posts

If one were designing a study where you only want to take more severe patients, then to me it makes much more sense when you have evidence that severe patients likely have the same abnormalities as mild patients, but those abnormalities are more pronounced.

My experience is that PEM is always severe no matter how 'mild, moderate or severe' the patient.

My PEM was always severe even when I was feeling 90% 'recovered' improved years ago.