POLL: physical vs cognitive PEM - same or different?

[Ravn]

Full poll question:
Please compare your typical PEM from physical overexertion with your typical PEM from cognitive overexertion. Consider the typical range of symptoms you get in each case, plus their timing and severity. Do you feel both types of PEM are fundamentally the same process or do they feel fundamentally different? Please use the comments to explain further.

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There are several polls on aspects of PEM already but no in-depth direct comparison between physical and cognitive, hence this new poll and thread. Plus most of the polls are members-only but I thought having a public discussion might increase general awareness of PEM from non-physical activities, especially if there happen to be some non-member researchers taking a sneaky look at the forum (you're welcome to join ).

This poll is intended to spark focused discussion about the similarities and differences between PEM following physical vs PEM following cognitive exertion.

I know there may be other things leading to PEM like social exertion, sensory overload and orthostatic effort, and that many activities involve several different types of exertion. But trying to include every permutation was getting too complicated and anyway, for the purpose of analysing possible differences I think it's best to concentrate on examples that are as close as possible to purely physical and purely cognitive activities. Fewer confounding factors.

Clarification on poll option 3:
Some people report they get the same set of symptoms in both types of PEM but that the timing is very different, e.g. PEM always hits immediately after cognitive exertion but after physical exertion it typically hits after a delay. So that would be one example for choosing option 3. Another example would be if half your symptoms occur with both types of PEM but you get an additional set of symptoms with physical PEM only.

Clarification on 'fundamentally the same' or 'fundamentally different':
Say you get brain fog with both types of PEM but it's a little worse with PEM after cognitive exertion. That would still be classed as fundamentally the same. But if you get massive brain fog after cognitive exertion and minor brain fog plus a pounding headache after physical exertion, that would be fundamentally different. So we're looking for the big picture patterns, not for minor detail.

All a bit shades of grey, I know. But the poll is just meant to get the thinking going. The resulting discussion will be the really interesting bit. Or that's what I'm hoping anyway.

 

[Kitty]

I'm not convinced I can recognise PEM from cognitive activity. I might have to read several descriptions to know whether or not I get it, and whether or not it's different to PEM from physical activity.

My response to too much concentration is usually after reading, and consists of a tight headache and my eyes flatly refusing to go on focusing. When reading something challenging or unfamiliar, this usually happens after less than 10 minutes.

I don't know whether it results in PEM, though. It's possible I can't do the activity for long enough to trigger it.

 

[Invisible Woman]

As @Ravn says many activities will involve different types if exertion.

Cognitive activity -
If I were in the same state PEM will occur much sooner & the deterioration is more rapid with cognitive exertion. I may still have a collection of general physical PEM symptoms that constitute "malaise" the overwhelming one will be an inability to think straight. I will lose maths and communication skills, forget how to operate the kettle and so on.

Physical activity -
PEM from a primarily physical activity will trigger the general group of symptoms that are hard to separate out and identify individually and altogether leave me feeling awful. It can happen immediately if I am attempting a task beyond my current limits, or it can take up to 3 days for noticeable PEM. The delay has changed with both time and illness severity.

Cognitive function will be significantly impaired but to a lesser degree. However, with physical PEM the muscles that were primarily used to carry out the activity will be very painful & much weaker. Unlike when healthy, gentle movement of the painful muscles does not alleviate the pain and stiffness, it make it worse.

Delay in appearance of PEM -
Sometimes when people (not necessarily pwME) feel ill, it is their own immune system fighting the illness that triggers mist of the noticeable symptoms. I wonder with PEM if the symptoms we experience are just a part of what us actually happening. Is it possible to be in PEM but not yet have noticeable symptoms, or the symptoms to have disappeared before the body has fully recovered?

For years I tried to manage my ME by being as active as I could without triggering PEM & avoiding more aerobic activity. So yoga, Pilates, gentle walking. I wonder if I was managing it too close to my PEM threshold, assuming that the threshold is where noticeable symptoms start, and that might have caused increased severity.

 

[Keela Too]

To me, most aspects are fundamentally the same, but a few may differ. I ticked option 3.

 

[Mij]

I have never experienced delayed cognitive PEM unless it was combined with physical PEM. I recover from cognitive PEM within an hour if I rest, wear ear plugs in a dark room. The physical PEM is delayed by approx 12-16 hours and takes a minimum of 3 days to recover.

I feel nausea/unwell with both though.

 

[Mij]

To add . . . cognitive PEM does affect my gait and at times cause sore/tired calf muscles if I really overdo.

 

[TigerLilea]

I only get PEM from physical exertion. I didn't realize that some of you get PEM from cognitive exertion also.

 

[NelliePledge]

It’s hard to separate out the orthostatic intolerance effect from the cognitive exertion. I didn’t realise about orthostatic intolerance when I was still working.

sitting at my desk working on the laptop was pretty exhausting, taking part in teleconference meetings was really draining

attending a lunchtime event where I was on a stall giving out leaflets and talking to people partly standing up partly sitting down was when I first consciously experienced sensory overload from the noise of lots of people talking made it impossible for me to hold a coherent conversation my head started to spin and I had to leave the event.

i feel like it is layers of effects

 

[Graham]

If physical or mental function set up cognitive payback, that would explain why I can't really work out what my answers should be. I really don't know. And don't tell me I should keep a diary – that takes up too much energy, and I don't want to waste mine!

To be honest, I either feel generally yuk or generally tolerable.

 

[Mij]

sitting at my desk working on the laptop was pretty exhausting, taking part in teleconference meetings was really draining

How do you feel when you're lying down reading with your head propped up a little?

 

[Hutan]

Is it possible to be in PEM but not yet have noticeable symptoms, or the symptoms to have disappeared before the body has fully recovered?

When I did the 2 day CPET, I had full-on PEM the night after the first test - the feeling dreadfully unwell, the pain that felt like my lower limbs had been crushed, sore throat. I was in a trial, so the second test was 48 hours after the first one, and by that time, I was feeling fine again, feeling as though I had no PEM, both before getting on the bike and during the test. And yet, the test showed a significant drop in a number of things, including work rate at ventilatory threshold and VO2Max. So yes, I think it is possible to have PEM and not feel it - or perhaps more accurately, to have ongoing and significant effects from exertion, but not be aware of them.

On the topic of this thread, I ticked 'they feel fundamentally the same'. I am constantly surprised by how cognitive exertion can give me PEM. The week before last was a busy one, proof-reading my daughter's thesis prior to its submission. I am still dealing with the after effects. There's the lying in bed feeling as though my body has been crushed, there's the missing the hole of the door and walking into the door frame. I have an infection that I can't shake off, even with antibiotics. Instead of being able to function, slowly and with rests, but function, for most of the day, by midday I have to go to bed to lie down. My walking is slower and the couple of steps up from the lawn to the deck take conscious effort to climb - the power in my leg muscles is much reduced. I start to get dizzy doing the dishes or standing to prepare food. I find it hard to think about complicated things and can't sustain high level thought for long.

I've had plenty of times to test whether cognition causes PEM, not least because I have done proof-reading for both my children as they have gone through university. Being upright almost certainly contributes - thinking isn't so hard when I am lying down. It's probably the social interaction as well as the quiet thinking, and the sustained nature of the exertion. But I'm pretty certain that sustained focused thinking causes PEM for me in much the same way that physical exertion does.

Two or so months ago, I did a lot of research and evaluation (a lot relative to my usual level) followed by two days of video calls. Sustained by coffee, I managed to keep thinking through the calls. I think adrenalin kicks in too. But there is a price to pay later.

 

[NelliePledge]

How do you feel when you're lying down reading with your head propped up a little?

I do most of my time online these days slouched down on sofa with my feet up and I’m ok for quite a long time for browsing and simple messaging.

Doing more complicated tasks that have more steps need a lot more concentration like filling in a form or editing text definitely has an egg timer on it where I need to stop.

i rarely read books due to maintaining concentration I used to read a couple of books a week but a handful a year now.

 

[alktipping]

i answered 3 . i always get a sore throat even when the activity is just reading threads this is usually the first sign that i have passed my limits i also tend to walk into doorframes when in pem spatial awareness must take up more energy than anyone would think .

 

[Kitty]

i always get a sore throat even when the activity is just reading threads this is usually the first sign that i have passed my limits i also tend to walk into doorframes when in pem spatial awareness must take up more energy than anyone would think .

That's really interesting, and has perhaps convinced me a little more that I don't get it. Those two symptoms are the most reliable indicators that I've overdone things, but I've never had them after working on a computer – not even after spending many hours redrafting and reorganising someone else's funding application, which can be hard work cognitively when you're unfamiliar with the project.

 

[ahimsa]

I didn't answer the poll because it's just too hard for me to disentangle all the different types of exertion.

I think I'd have to purposely structure my activities to avoid different types of exertion for a while and then carefully record what happened. It's too hard to try to do that type of experiment.

I know I could not trust my memory. Back in the early years of my illness, when I took my husband with me to a lot more doctor appointments, I once told the doctor that I had not had a migraine in several weeks. My husband looked at me and said, "But you just had one on Tuesday!"

I honestly did not remember. I was not trying to be a "model patient" or anything like that. It just had completely slipped my mind.

Anyway, it's an interesting question!

 

[Ravn]

Is it possible to be in PEM but not yet have noticeable symptoms, or the symptoms to have disappeared before the body has fully recovered?

I think that must be the case. The physiological changes underlying PEM must surely start during exertion, there can't a be a switch that suddenly flips all by itself 24 hours later or whatever your personal delay is for PEM symptoms to appear. So in that inbetween period we technically have a PEM process going on but it's asymptomatic or presymptomatic or subclinical or whatever you want to call it.

What I'm not sure about is whether it's possible to have such a mild case of "asymptomatic PEM" that you never realise you had it, provided you rested enough after the initial exertion.

What I am sure about is that when I do a second activity during that symptom-free inbetween period, the whole PEM episode will be worse and last longer than if I had started resting straight after the first exertion.

And don't tell me I should keep a diary – that takes up too much energy, and I don't want to waste mine!

I think I'd have to purposely structure my activities to avoid different types of exertion for a while and then carefully record what happened. It's too hard to try to do that type of experiment.

Please, nobody experiment or overexert in any way just to answer the question! Going by memory is a bit tricky, I agree, but I find once I decide to pay more attention to a certain phenomenon I remember future occurrences much better (and despite my best efforts at avoiding them there will be future occurrences of PEM I'm afraid). Of course I then forget other stuff instead, there's only so much room in my brain.

 

[Keela Too]

What I am sure about is that when I do a second activity during that symptom-free inbetween period, the whole PEM episode will be worse and last longer than if I had started resting straight after the first exertion.

The phrase “dangerously okay” applies to this time.

 

[Snow Leopard]

The replies to this thread have certainly been more interesting than what is typically written about PEM... Thanks to @Ravn and the others who have replied.

 

[Mij]

The physiological changes underlying PEM must surely start during exertion, there can't a be a switch that suddenly flips all by itself 24 hours later or whatever your personal delay is for PEM symptoms to appear. So in that inbetween period we technically have a PEM process going on but it's asymptomatic or presymptomatic or subclinical or whatever you want to call it.

Yes. The thing is that pathophysiology of PEM is there from day one of developing ME, even if you don't experience it until 11 years into the illness like I did. ME is PEM.

 

[Trish]

I wasn't sure I got PEM from cognitive overactivity until recently. I think when my ME was mild and i was pushing myself to and above my energy limit in all aspects (physical, cognitive, social, emotional) at the same time as a teacher and parent, I attributed my PEM to overstepping physically.
In that situation my PEM symptoms are both physical and cognitive.

Now that my ME is severe physically, and still relatively mild cognitively, again it has been physically doing too much beyond my now much shrunken envelope that has triggered PEM that includes both physical and cognitive worsening.

But several times over the last couple of years while staying within my physical envelope, I have pushed myself hard cognitively, and found to my surprise that I am in a much worse cognitive fog for days afterwards, while also feeling slower physically, but without my full range of physical PEM symptoms.