Elevated Perceived Exertion in People with ME/CFS and Fibromyalgia: A Meta-analysis, 2020, Lindheimer et al

Andy

Andy

Senior Member (Voting rights)
Purpose
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia (FM) are two debilitating illnesses primarily characterized by chronic symptoms of fatigue and musculoskeletal pain, respectively. Some investigators have observed an elevated sense of effort in these patient groups, however, this effect has not been substantiated via quantitative review. As such, we conducted a meta-analysis of perceived exertion (RPE) responses to aerobic exercise in ME/CFS and FM compared to healthy adults.

Methods
Case-control studies involving adults with ME/CFS or FM that measured RPE and heart rate responses to acute aerobic exercise were included. Data sources included: PubMed, Scopus/Embase, CINAHL, CENTRAL, and Google Scholar. Risk of bias was assessed by evaluating each study’s description of participant characteristics, matching procedures, and administration of RPE scales. Hedges’ d effect sizes for RPE were calculated and aggregated using random effects models and potential moderators were explored with meta-regression analysis.

Results
Forty-one effects were extracted from 37 studies involving 1016 patients and 686 healthy controls. We observed a large (Hedges’ d=0.85; 95% CI: 0.62, 1.08) effect indicating higher RPE in patients than controls. The mean effect size was significantly moderated (p<0.001; R2=0.38) by whether RPE data were analyzed at a peak or submaximal intensity (b=0.60, z=4.6, p<0.001) and the type of patient group that was studied (b = 0.25, z = 2.08, p=0.04).

Conclusions
People with ME/CFS and FM perceive aerobic exercise as more effortful than healthy adults, but the exact causes are unclear. The large magnitude of this effect merits further exploration of underlying mechanisms which could provide insight into the pathophysiology of ME/CFS and FM or the broader debate about the nature of central and/or peripheral signals that influence RPE.
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Paywall, https://journals.lww.com/acsm-msse/...ed_Exertion_in_People_with_Myalgic.96253.aspx
Sci hub, not available at time of posting
 
Conclusions
People with ME/CFS and FM perceive aerobic exercise as more effortful than healthy adults, but the exact causes are unclear. The large magnitude of this effect merits further exploration of underlying mechanisms which could provide insight into the pathophysiology of ME/CFS and FM or the broader debate about the nature of central and/or peripheral signals that influence RPE.

So... exercise is more difficult for sick people? This is ground-breaking science! Who knew?
 
:emoji_face_palm:

I'm confuses. Are they talking about PEM or aerobic exercise.

I've known 3 people with FM in real life who didn't experience PEM after over exertion or exercise.

I personally don't perceive exercise as "effortful" for the most part. My issue is how I feel the next few days when I go over my energy 'window'.
 
I don't understand how personal judgment from a stranger with no insight into the experience can actually be considered a serious scientific metric.

In all of this, the idea that the perceived effort is not matched by real effort is a judgment of no actual merit, entirely personal and based on nothing but ignorance of what the actual effort is involved.

Because worst of all it all hinges on the god of the gaps. Not only is it poor judgment with no merit, it is based entirely on the introduction of a magical element to the mix, no better than ascribing the cause to ghosts or cosmic dragons.

Do 100x better than this.
 
This is a meta-analysis done by veteran's affairs and includes a sports medicine expert.

It actually comes to a less bad conclusion than I would normally expect. Or to put it differently, the language used seems less aggressively psychologising and open to the phrase 'we don't know'. Baby steps.

Or maybe I'm missing something.

I think there are rather few good studies in this area to begin with.

It does make me think (just off topic a bit) of doing a meta-analysis of CBT treatment papers where we measure the perceived effort of the researcher to create (and follow through on) a robust study plan vs the real effort. Full disclosure, I think I have a pre-conceived idea as to how that will turn out. :D
 
Patients who have various symptoms associated with illness tend to have an increase baseline in their effort reporting associated with these symptoms, but the rate of increase in effort during aerobic activity is normal (given the level cortical output), when normalised to that increased baseline.
 
Mij said:
I personally don't perceive exercise as "effortful" for the most part. My issue is how I feel the next few days when I go over my energy 'window'.
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Me neither, and it seems to be consistent across the mild/moderate patients I meet face to face. When fully rested we can all do tasks with an aerobic component, and we feel great whilst doing them. Then tomorrow dawns – and worse still, the day after that. Our experience seems to be the opposite of what is reported here.

ETA: removed stray 'of'.
 
Kitty said:
Me neither, and it seems to be consistent across the mild/moderate patients I meet face to face. When fully rested we can all do tasks with an aerobic component, and we feel great whilst doing them. Then tomorrow dawns – and worse still, the day after that. Our experience seems to be the opposite of what is reported here.

ETA: removed stray 'of'.
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Hmm. I wouldn't say that described my experience. For example even when ME was mild enough to work part time and I'm sure I wasn't deconditioned, I still experienced rapid muscle fatiguability. So if I walked more than about 200 metres, my legs would feel heavier and more painful and if I tried to keep walking without a rest my legs would feel like they were going to collapse.

Similarly with climbing stairs. I could climb one flight apparently normally at healthy pace, but if I tried to climb another flight my legs would struggle. It was completely different from feeling tired when healthy, it was a feeling like my muscles were failing. And I never felt great while doing physical activity, except perhaps for the first few metres if I was well rested.

It's the same now my ME is more severe, but the distances and number of stairs are drastically reduced before my legs collapse.

PEM is different. It's my whole body feeling sicker the next days after overdoing activity.

Edited spelling.
 
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'failing' is an 'important' word.

Mine rarely fail totally, what happens is the 'precision' and 'accuracy' diminish rapidly - so even when I, as I do, ignore the pain, and try harder, a point is rapidly reached where, even to my failing cognition, it becomes obvious that there is no point.

Sometimes this even happens before things, or myself, become broken.
 
I definitely have an 'energy envelop', so I can predict how much I can do before I need to get off my feet and lie down. But I do have periods or just a day or two, when I can't climb a flight of stairs. It doesn't give me PEM, it's just that I can't walk too far or climb the steps. I don't think my ME is progressive because I eventually go back to baseline.
 
From my reading about the 2 day CPET test I got the impression that patients did not realise how much effort it was taking them to do what they did. Healthy people had a sense of when they were expending 10% of their energy when they actually were, but Me patients thought they were using less than it was taking them. This was worse on the second day.

People who described their experiences often said that they thought the test was not showing up ME because they did not feel they were managing less on the second day (we all want a positive test!) and were surprised when they got their results.

ME doctors have said that their patients endure things much longer than healthy people probably because they have forgotten what normal is like.

It happens in MS as well. It is said that patients say they are fatigued but actually they go straight through fatigue to exhaustion very quickly so carry on when a healthy person would stop for a rest.

It makes sense for me as well. If I did not do anything until I felt well enough I would do nothing at all.
 
Perhaps some of the increase of the perceived effort by patients is the result of the extra mental effort in keeping track of abnormal bodily sensations in order to distinguish whether or not one is doing too much.
 
"People with ME/CFS and FM perceive aerobic exercise as more effortful than healthy adults, but the exact causes are unclear."

First thought. If an ultra strong person picks up a large sack of potatoes, their perceived exertion will be pretty trivial. If someone much weaker does the same thing then their perceived exertion will be much higher. Even the same person doing the same thing they normally do after a bout of strength sapping illness will notice a significant difference in how much harder it seems to do something. If one person is weaker than another, due to physique and/or illness, then the perceived effort to do the same thing will be higher.

Not read this, but I wonder if they are controlling for people having the same physical strength, but having different perceptions of effort?
 
shak8 said:
Perhaps some of the increase of the perceived effort by patients is the result of the extra mental effort in keeping track of abnormal bodily sensations in order to distinguish whether or not one is doing too much.
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Would be interesting to compare with predictable easy effort vs. unpredictable effort that requires attention and coordination. Basically things that can be done automatically without thinking, like simply cycling, or things that require coordination and finer movements.

If I'm doing something that requires even a bit of attention I have to plan for every step ahead of time, and there can't be too many steps or I have to pause and plan, and basically lose my track if something doesn't go as planned and I have to reassess. It usually works but only on simple things, especially so if I am standing, which drastically lowers my ability to think and coordinate.

If I have to make careful movements such as this I quickly get to the point where I have to strain every movement, bit like if it was freezing cold and trying to work against stiff muscles that resisted. Which is also the case with PEM, my muscles become very rigid and every movement is a strain against the stiffness.
 
rvallee said:
If I'm doing something that requires even a bit of attention I have to plan for every step ahead of time, and there can't be too many steps or I have to pause and plan, and basically lose my track if something doesn't go as planned and I have to reassess. It usually works but only on simple things, especially so if I am standing, which drastically lowers my ability to think and coordinate.
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Definitely matches my experience.

It would be marvellous if there were some way of measuring or defining pre illness performance as different individuals vary.

This was something I was very good at pre illness. I could keep not only where I was in relation to project milestones clearly in my head but also where other team members where, who needed which tasks to be completed before their next task could start and so where to redirect resources as necessary.

Now I can struggle to make a cuppa.
 
shak8 said:
Perhaps some of the increase of the perceived effort by patients is the result of the extra mental effort in keeping track of abnormal bodily sensations in order to distinguish whether or not one is doing too much.
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I suspect the perception of higher effort is simply because the actual effort is higher because of illness related lower physical capability.
 
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