PEM - Post-exertional Malaise - what it is and where it fits with ME/CFS

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    In the PEM recovery tips thread, a discussion developed on what PEM was, and whether it was a key feature of ME/CFS. Rather than derail that thread, and because it's a question and concept that well and truly deserves its own discussion, I've moved it over here, making copies of posts that belonged in both conversations - if anyone thinks I've missed anything, please let me know :).

  • [This is a copy of PaulB's message from another thread - it's in both threads, as it's the post where the conversation started to diverge]

    I'm really interested in chatting about this.

    @river and I briefly noted PEM in a different thread, and I know @river you experience it as a central part of your ME/CFS.

    I'll count myself lucky - it has not been a part of my general situation for a long time. It was in the past. It is on generally rare occasions. But most of the time not, and I'll potentially explain that more at some point.

    I am keen to understand it in others more.
    I see myself as a thinker, and I like to solve puzzles ...

    Towards that, and as an entry reflection for myself, I'll note it interesting ...

    that this website: describes PEM as a "hallmark symptom" of ME/CFS,

    whilst this website
    says that "the main symptom of CFS/ME is feeling extremely tired and generally unwell" which to me is a similar but different thing - a more overarching thing.
    After listing 8 subset symptoms, it then says "Most people find overexercising makes their symptoms worse" - which I think is getting at the PEM.

    I mean no great statement from this. I'm just interested that, for some, it is central, and genuinely so.
    And in others it is not as central. It is a thing to be alert to, but it is a part of a broader landscape.
    Again, neither is right or wrong. But it is something I will try and think about ... see if I can get a better understanding of.

    That's probably enough bulk to this email.
    I will finish with a final couple of questions I'm considering ...

    what is a more detailed description of the malaise?
    is the malaise generally the same, or will different exertions give rise to different malaises?
    thanks for bearing with me folks,

  • @PaulB for me - different exertions definitely given rise to different malaises.

    Cognitive exertion = insta-PEM. It can be crushing, nauseating, syncope-inducing, especially if I try to push through the onset. If I've only overdone it a little bit cognitively, sometimes this can be temporarily reversed by immediately lying down with my legs elevated (to promote blood flow to the head) and hydrating well. But it'll catch up to me in the end and result in multi-week-long insomnia, headaches, brain fog and fatigue.

    Physical exertion = delayed PEM. The delay used to be about 24-48 hours but recently, I assume due to some new supplements, it's been more on the order of several weeks which gets very confusing. The last time I had an obvious episode of physically induced PEM was after showering. I felt fine, just a little hot and sweaty afterwards.. But woke up the next morning feeling like I'd been hit by a truck. I recovered in a few days with aggressive rest, thanks to new meds.

    I wonder if PEM plays less of a role in patients whose baseline severity is higher? If you're already at rock bottom, it's hard to get worse!

  • @river OK, the scientist in me has follow up questions 🙂

    I wonder if building capacity / tolerance is a thing PEM sufferers can explore. I suppose this is what the whole of pacing is getting at - but I was a little turned off that field of discussion given the controversies of the British origin story of it.
    So, I'm going to go with capacity.

    e.g. I wonder if a 10 second shower - not too hot - with no other major influences in the day (I know - how easy is that to manufacture) would lead to a crash?
    If it did - interesting. What is going on there - is it less the physical exertion and more the environment of the shower?

    If a 10 second shower doesn't lead to PEM, what about a 20 second shower next?

    On a similar but different topic, I've had great success in building my memory/concentration capacity. I was put onto an app by a cognitive specialist; it is fun, and free, and is called Lumosity. Games take around 2 minutes each - 3 come for free each day - and you can do them each as many or as few times as you want.
    I needed to manage addiction to it - but once through that, have benefitted from it I think demonstrably.
    For those for whom cognitive overload can lead to PEM, it may be too much I suppose. Certainly in severe cases. But for mild situations, it could work. More difficult / taxing games can be avoided. Games can be done just for a few seconds and then stopped.

    OK, off to bed for me ...

  • @PaulB said in PEM - Post-exertional Malaise - what it is and where it fits with ME/CFS:

    I suppose this is what the whole of pacing is getting at - but I was a little turned off that field of discussion given the controversies of the British origin story of it.

    Are you referring to graded exercise therapy? This is not what most people mean by pacing, I think. Pacing is about reducing activity to a manageable level (which sometimes means very drastic activity reduction).

    For me PEM is pretty directly tied to my heart rate. Like most people with CFS I have both an elevated resting heart rate (more so when in PEM) and abnormally high heart rate in response to mild exertion. This means I go over my "limits" very easily. My heart rate at maximal exertion is also quite a bit lower than the predicted max heart rate for someone my age. It plateaus at 150-160, but my predicted max is 196bpm! These abnormalities are consistent with the existing research into cardiovascular performance in CFS.

    I was on a drug to lower my heart rate for about 4 months and it made a huuuge difference to my exertion tolerance. I still got PEM occasionally but it was much less frequent because fewer activities took me over my limit. However it also made me really sick in a different way, and from this I've drawn the conclusion that my elevated heart rate is a compensatory mechanism for some kind of deficit (perhaps reduced cerebral blood flow - which has also been a common finding in CFS research, incidentally!) and just happens to cause severe fatigue as a side effect. I read that the heart uses the most energy of any organ in the body, besides the brain. So it's not surprising that a compensatory mechanism involving an abnormally high heart rate would also cause fatigue.

    [edited to remove personally identifiable specifics about heart rate, but @PaulB if you would like to know those feel free to send me a private message]

  • @river Love it - you're right into the investigation!

    I'll try and get time through the day to engage with some details ...

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    @PaulB said in PEM recovery tips:

    whilst this website
    says that "the main symptom of CFS/ME is feeling extremely tired and generally unwell" which to me is a similar but different thing - a more overarching thing.
    After listing 8 subset symptoms, it then says "Most people find overexercising makes their symptoms worse" - which I think is getting at the PEM.

    Just for info (and this is for general information, and is in no way questioning your diagnosis - PEM isn't always easy to pick, and as per River's experience, if the delays are quite long, can just feel like random variations in function), PEM is generally considered one of the core symptoms of ME/CFS - definitions like those used by the NHS are based on earlier research that was heavily informed by the now-scientifically-discredited (but still followed by many mainstream medical professionals) psychosocial model of the illness (on the NHS page, you'll see a link noting that new guidelines are being drawn up - the good news is that these sound like they'll far better reflect current knowledge of the illness). A good place to start on the diagnostic criteria for ME/CFS is Emerge's page on the issue:

    @river said in PEM recovery tips:

    Physical exertion = delayed PEM. The delay used to be about 24-48 hours but recently, I assume due to some new supplements, it's been more on the order of several weeks which gets very confusing.

    Much sympathy - I imagine planning around that (let alone getting a feel for what works/doesn't) would be both difficult and challenging.

    @PaulB said in PEM recovery tips:

    I wonder if building capacity / tolerance is a thing PEM sufferers can explore. I suppose this is what the whole of pacing is getting at - but I was a little turned off that field of discussion given the controversies of the British origin story of it.

    As River says, it sounds like you're talking about GET (Graded Exercise Therapy) - Pacing is well accepted in most patient communities, as well as educated medical professionals, as the main treatment management protocol. GET, on the other hand, harks back to the psychosocial model, and has been found to have caused significant harm in many people with ME/CFS through triggering PEM and pushing people through it, in some cases leading to permanent reductions in function. There are still mainstream medical professionals and researchers that advocate GET, but thankfully the science is making its way through the community and both the number and their influence is diminishing over time. Some of these have "re-labelled" pacing as GET, but this is smoke-and-mirrors to limit damage on reputations. Emerge also has a great fact page, with a linked fact sheet, that are well worth a look:

    @PaulB said in PEM recovery tips:

    For those for whom cognitive overload can lead to PEM, it may be too much I suppose. Certainly in severe cases. But for mild situations, it could work. More difficult / taxing games can be avoided. Games can be done just for a few seconds and then stopped.

    I've also had some success with brain-training type games - as you well say, done sensibly in a way to avoid PEM, they can help with brain function - although during PEM (to get back to the topic at hand) they might be less appropriate, or at least better to be done less.

  • As you can tell, I haven't gotten into the naming conventions.

    You guys are right - the British thing was graded exercise theory, wasn't it.

    I'll try and chat more later today ...

  • I've hopefully got some time and opportunity to workshop more ... so here goes ... a few false starts, but now here goes.

    I find the discussion here really interesting.

    In terms of this thread, PEM recovery tips, I think it good to get a sense of the thing we're talking about. How does it work in with CFS. e.g. is it a defining feature, or is it a prominent, very common feature.

    And as PEM does / will potentially have a very prominent place in peoples' understanding, including the broad medical profession, I think it important to have a good think about it - to give it a bit of a prod and a poke.

    Before I get in to it - a note: I respect any or all of your rights to disagree with what I'm about to say.
    I am trying to tease out the concepts - for my own sake if not for anyone else's. But if anyone can read through my thinking, thank you and power to you. And if you want to debate the ideas, great.


    OK, so post-exertional malaise. Seems to be 2 parts to the concept: the PE bit and the M bit.

    First, the M. Malaise. The first medical dictionary I found says "a general feeling of discomfort, illness or unease whose exact cause is difficult to identify".
    So, what if I've got a pretty good idea of what is causing a particular fatigue / discomfort / illness? If I don't have the difficult-to-identify feeling, is the cause-identified feeling not a part of CFS? I think it can be.

    OK, maybe that definition is not what was intended here in this context. Let's go with "general feeling of discomfort".
    So, what if it is not a general feeling of discomfort I have, but a specific one? e.g. it is a terrible feeling in my legs, or in my heart, or in a host of other specific places in the person. If I generally don't have the "general" feeling, is the specific feeling not a part of CFS? I think it can be.

    Alright, maybe we define malaise as "feeling discomfort, illness or unease". Sounds better to me. A pretty broad definition - but, note, not one that lines up with the definition of the M word in all medical dictionaries and general dictionaries.


    OK, now the PE. Post-exertional.

    What of the poor feelings for people who wake up from sleep? Sleep should not be treated as exertion by this medical definition. Sleep is rest. It is difficult for us, but I think it troubling if we treat sleep as exertion.
    I know very well that our bodies are often over-working when we're trying to rest. I have muscles in pain right now that can attest to it. But that is not the intention of the described activity - sleep. Sleep is not exertion. Going for a walk to the letterbox is. Putting on clothes is. Doing a sudoku is. It can be trying to remember someone's name. Sleep, no.

    Same with reactivities. What of the poor feelings for people after eating particular foods, say? I don't think reactivity should be treated as exertion.
    Yes we need to put energy into chewing, and digesting. People who get tired because of those aspects of eating - that is no good.
    But those of us who react to particular foods, or smells, or light / sound / texture, etc. etc. that is not feeling poorly because of exertion. That is feeling poorly because of something other than exertion.


    I could go on with examples. I will spare us all that 😉
    Instead, I'll try and round out a conclusion.

    I think PEM a good concept. I think it a meaningful and helpful concept.
    I think it works for a whole heap of people with ME/CFS, especially in the early phases. And lots of people in the mid and later-on phases too.

    But I'm not comfortable with it being a key / central / if-it-doesn't-fit-you-you-might-not-have-CFS concept.

    It is my sense that it is possible to have CFS without PEM being a majorly applicable concept then and there.

  • @PaulB in the context of CFS diagnostic criteria, I have usually seen "malaise" defined as all of the individual, specific symptoms that constitute the diagnosis, and PEM as a whole defined as a worsening of said symptoms after exertion. This doesn't mean the symptoms are not present at other times.

    The two examples you give are the specific symptoms of unrefreshing sleep, and new allergies/intolerances, both of which may get worse after exertion, but are also likely present to some degree at all times.

    I understand where you are coming from, however. Until science understands the underlying cause of this illness, any diagnostic criteria we come up are going to be imperfect and might not perfectly describe everyone's experience. There a probably distinct subtypes of CFS, for example, that may have different underlying causes though they ultimately result in a similar syndrome. No research has examined the illness with the goal of determining subtypes yet, as far as I know. Have you heard of the Australian ME/CFS biobank? I think this is something they are interested in doing.. But I can't for the life of me find the email where it's mentioned now. (or maybe that was DecodeME in the UK? Either way it was some kind of genetic biobank thingy)

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    The conversation has now been moved over 🙂 I'm sorry, as due to making copies of some posts I ended up having to make copies of all the posts, as otherwise they were out of order. This means some upvotes disappeared, but otherwise it should be as it was, just over here.

    On the topic at hand, in terms of definitions of PEM, rather than looking at dictionary definitions, I'd suggest looking at how it's discussed in ME/CFS diagnostic criterion. The 'big ones' (ie, the ones that seem to have the most weight on the non-psychosocial medical side, and in patient and advocacy groups) seem to be:

    I have this sneaking suspicion I've forgotten another one as well.....

    These are the criterion that are generally used to define the illness by researchers or (educated) practitioners, as long as the psychosocial camp aren't involved. However, as River also well says, there's still a lot not known, and it's important to recognise that the manifestations of PEM can vary significantly between different patients and different situations.

    There are some older criterion that are less well regarded, like the Fukuda definition, and another one of similar vintage and wooliness. These are less well-regarded, and the NHS criterion you mentioned above seems to stem from this earlier period.

    Note that while PEM is a key feature in all of these criterion, it's not the only feature - so as River says, unrefreshing sleep is there, separate and distinct from PEM.

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    One other thing that came to mind overnight (I get very interrupted sleep, and often have thoughts in the gaps between sleep) - it's possible in very-well managed ME/CFS amongst people with a relatively 'mild' (noting that there's nothing easy, nice or pleasant about mild ME/CFS) to have rare or, at least theoretically no, manifestations of PEM. Someone able to live at their own pace, with no shocks (such as illness) to knock them around could potentially not have PEM - this doesn't mean they don't have it as a symptom of their illness (as if they pushed outside the energy envelope, it would crop up soon enough), but due to it being very well-managed, they don't have to deal with it flaring up. It'd be like someone with reflux who had appropriate diet and medications not having to deal with symptoms, because it was treated, but that doesn't mean they don't have reflux.

    For example, back when I was very much mild (again - not fun at all - it was all sorts of unpleasant - but what I would give to be that well again now!) I was able to work five days a week, and the PEM was generally resolved overnight, and was very mild (so, for example, reading descriptions of PEM here I may not have recognised it). Now, I'm not happy to report, it's a very different story!

    Of course, for most of us, the pressures of real-life (illnesses, work if we're well enough, and if we're not well enough then things like showering or self-care like brushing teeth can be enough to trigger it) mean that it's very unusual for this kind of situation to crop up.

  • @Daffy_Dave PEM seems to be the medical consensus and finite criteria for ME to exist, as a diagnosable illness/disease. CFS seems to be discussed as a sub-set of this. Have I interpreted the reading correct. Without PEM the diagnosis is questionable and the patient fits more appropriately into the CFS sub-set. I can only explain PEM as the reactive body/brain response to the illness as a whole, requiring all reserves of energy to be redirected to the correcting of the dysfunctions. There is no control over this response. It will be and always has been the brains constant struggle to correct and stabilise a somewhat disrupted and fluctuating balance.
    I am purely trying to describe the illness and PEM as I believe it is, through the longevity and first hand experience of it all. The extremity of PEM is that vital body functions can shut down without warning and may not reboot in a timely manner as we would all like. Sometimes it remains as a permanent lingering state... I have often felt that PEM is not the correct way of describing or communicating the state. The word ''post'' for me has never sat well. I think ME/CFS is the extreme and chronic dysfunction of body systems internally that are in a constant abnormal, aggravated and fluctuating state -all trying to recalibrate and compensate for the dysfunctions. It is the extreme of the fluctuating constant abnormal state, that presents itself as a shut down, requiring longer time to restore to a lower level of dysfunction. Please this is not a definition but an attempt to describe, in order for me to understand what's going on with my body.
    In simpler terms, the body has reached it's limit and the brain and only the brain will decide when to correct it.🤓

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    @crashdummy I'll reply twice to your message. The first is as a moderator, to clarify the position of Emerge (and thus the forum) on "the great name debate" (which has come up, implicitly, in your response, which talks about CFS as a 'subset' of ME - which is something that some groups advocate for, but not a position for which there is robust scientific support).

    Naming conventions for ME/CFS - Emerge/Forum position

    The current position of Emerge Australia is to utilise the term ME/CFS as an umbrella term to reference all diagnoses of myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS), and ME/CFS. This is due to our belief that research has not yet confirmed whether the illness is one condition, two conditions (ME and CFS), several different conditions or a condition with several subgroups.

    Over the course of time, ME/CFS has been given many different names, including post-viral fatigue syndrome, Royal Free disease and, most recently, systemic exertion intolerance disease (SEID). There is much contention and debate as to the most appropriate name, and this has contributed to confusion and scepticism within the broader community.

    ‘Chronic fatigue’ is a symptom of many medical conditions, including things like cancer or multiple sclerosis, but it is not an illness in its own right. While profound fatigue is a symptom of ME/CFS, people living with the condition experience a wide range of other symptoms as well. Emerge Australia believes that ‘chronic fatigue’ should not be used as a name for ME/CFS, because it perpetuates the misunderstanding that the illness is primarily tiredness.

    We consider that regardless of what name is used, post-exertional malaise (PEM) is the defining feature of this illness. PEM occurs when some or all ME/CFS symptoms are exacerbated after physical or cognitive exertion, leading to a reduction in functional ability.

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    @crashdummy Replying as a 'normal person' (my wife may not agree with this diagnosis 😉 ) :

    As per the previous post, PEM is expected to be present as part of ME/CFS - and the distinctions to this are usually created by assigning the term "CFS" to the earlier diagnostic criterion (like Fukuda and "ME" to the later criterion (and the 2011 ICC criterion specifically does this, but it didn't really "stick" broadly and has created no small amount of contentious discussions in patient groups) and ME to later criterion (such as those I've linked earlier in the thread).

    However, until we have robust, readily available diagnostic tests (which, thanks be, seem to be drawing ever-closer), and due to the difficulties in identifying PEM clearly (it's easy as pie for moderate and above, but as per my example in my earlier post, for some people with mild ME/CFS it can exist but either be very well managed, or so mild it wouldn't be recognised as PEM when people like you or me talk about it), I don't think there's a lot of value in trying to potentially arbitrarily split populations (particularly if there are issues of PEM identification - in which case some patient groups may end up with inappropriate treatments, and we've had enough of that with ME/CFS, however it's named, over the years).

    The way you describe ME/CFS as a constant, abnormal, aggravated and fluctuating state is interesting and resonates in no small part with my experience :). I think that beyond a doubt ME/CFS is an abnormal state - no two ways about it there. I think we might need to wait a bit more on the science to learn whether the fluctuating is due to the illness 'naturally' fluctuating, or it reacting to external stresses on the body. Aggravated as a term can have a broad range of meanings, but I think it could well be argued that there is underlying "aggravation" in terms of the symptoms that lead to unrefreshing sleep, for example.

  • @Daffy_Dave I appreciate your responses. Every time I read articles, or try to understand the medicine/science behind it all, it bamboozles me. 🙂

  • @crashdummy just thought I'd chime in to put a label on something - I think what you are describing in your post is the failure of the body to maintain homeostasis, which is definitely the defining feature of my own experience of the illness. In fact, it's the way I usually describe what ME/CFS is to people who know nothing about it. I was acutely aware of this the other day when it seemed I had to do all the work of regulating my body temperature myself 🥵🥶🥵🥶

  • @river I'm relieved to know that word exists. I had to look it up though ..haha... homeostasis, homeostasis... I've been repeating it all day. Very excited that you gave the label to what I was trying to convey ... Reading through some information is a slow going process for me. One, I may not recall the meaning of a word, or I may never have heard it! ... 🤓

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