Understanding Muscle Fatigue in Chronic Fatigue Syndrome

[*GG*]

Yes, very strange highlighting. Didn't (and couldn't) read the whole thing at all, but here's the conclusion from the 'provisional' PDF:

Conclusion

CFS/ME patient perceptions of the nature of their condition frequently cite ‘peripheral’ as opposed to a central origin, with many descriptions of their fatigue regularly referring to difficulty in maintaining muscle activity due to perceived lack of energy, or through muscle fatigue [15,17].

There is increasing evidence to suggest muscular bio-chemical abnormality may play a major role in CFS/ME associated fatigue. The literature suggests patients to exhibit profound intramuscular dysfunction regarding acid generation and clearance, with a tendency towards an over-utilisation of the lactate dehydrogenase pathway following relatively low-level activity.

However, the precise mechanisms underlying the dysfunction are yet to be fully elucidated. There is a real need for adequately powered studies to examine PDC function in vitro, to determine the mechanisms responsible for bio-energetic dysfunction and peripheral fatigue.

Just breaking this up

GG

 

[Tuha]

@msf I think is more a blood vessel issue, Because I have the same issue, If I am stuck middle of the stairs and cannot keep going I do turn off like a tv slowly, I stop talking, being unable to hear then all goes black (apparently as my husband moves me I shake) then a few hours later I come to consciousness.

If I remember correctly, Fluge and Mella are seeing an endothel disfunction in blood vessels. This could lead to a problematic oxygen distribution to our muscles and so on. The bigger this endothel disfunction is the more the ME/CFS patients disabled are.

 

[Valentijn]

So does someone help you up the rest of the stairs? What happens if they don´t?

I had a leg stop working following a long trek through an airport with really crappy service from the people who are supposed to help disabled people. It was a single large muscle on one upper leg, while the other muscles on that leg, and all of the muscles on the other leg, continued to respond in a fairly normal (maybe shaky) manner. I had feeling in that part of my leg, but it was completely non-responsive when I tried to use that muscle.

This suggests that the muscle itself was either out of energy or somehow had temporarily became too inflamed to respond. It wasn't a vague or widespread sensation of being too weak or fatigued to get up and walk to the bathroom. A problem of perception or other central dysfunction would not target a single muscle ... even if it was a nerve problem, it would not be so isolated but would impact elsewhere along the same nerve.

It resolved after a rather scary hour or so on the airplane.

 

[msf]

Just noticed this paper co authored by J Newton
Perceived fatigue is highly prevalent and debilitating in patients with mitochondrial disease.

I don't know why perceived is used here either but thought i'd mention it. Its seems completely unnecessary.

Ok, when it is used as a term in the title it starts to look a bit suspicious.

I´m leaning more towards it being a sop to Wessely, I would be quite surprised if she actually believes any of his nonsense.

 

[msf]

I had a leg stop working following a long trek through an airport with really crappy service from the people who are supposed to help disabled people. It was a single large muscle on one upper leg, while the other muscles on that leg, and all of the muscles on the other leg, continued to respond in a fairly normal (maybe shaky) manner. I had feeling in that part of my leg, but it was completely non-responsive when I tried to use that muscle.

This suggests that the muscle itself was either out of energy or somehow had temporarily became too inflamed to respond. It wasn't a vague or widespread sensation of being too weak or fatigued to get up and walk to the bathroom. A problem of perception or other central dysfunction would not target a single muscle ... even if it was a nerve problem, it would not be so isolated but would impact elsewhere along the same nerve.

It resolved after a rather scary hour or so on the airplane.

The problem with muscles literally running out of energy (if that is what happens) is that this could theoretically occur in a healthy person too, so you would have to show that it happens more often in patients with ME (which I´m sure it does). The fact that I, and I assume a lot of other people on this forum, have not experienced this however, suggests that it occurs in more severe cases, which is what I suggested before. If it occurs all the time in the bedbound then if anyone studied them you would hope that they would notice this, but if it only occurs every now and then it is fairly unlikely to be statistically significant in any studies (I don´t mean by this that it isn´t a serious concern, just that it is hard to measure).

 

[jimells]

Just noticed this paper co authored by J Newton
Perceived fatigue is highly prevalent and debilitating in patients with mitochondrial disease.

I don't know why perceived is used here either but thought i'd mention it. Its seems completely unnecessary.

This paper was a good find and explains that the word "perceived" is *very* important to understanding these papers:

we define perceived fatigue as an overwhelming sense of tiredness, lack of energy or feeling of exhaustion [1] employing a multifactorial approach; distinguishing this from physiological fatigue in which the focus is muscle and its ability to generate and maintain power. The premise of this study was to determine the magnitude and impact of self-perceived fatigue ...

I wonder if "self-perceived fatigue" can include "physiological fatigue"...

 

[Keela Too]

Hmmmm seems to clearly distinguish "you just feel tired" from "your muscles physiologically can't cope with doing more".

Nope - no good reason to use "perceived" in studies that are supposed to be about the physiology of the illness.

Actually - that's not quite true - I would be happy if it were used like this (my imaginary sentence):

During exertion ME patients often do not perceive the approach of that point at which they are likely to do damage to their health. This is due the fact that Post Exertional Neuroimmune Exhaustion (PENE), is often triggered before the perception of fatigue has become apparent.

 

[BurnA]

This paper was a good find and explains that the word "perceived" is *very* important to understanding these papers:



I wonder if "self-perceived fatigue" can include "physiological fatigue"...

I don't know why they complicate it further by adding the term self perceived fatigue.

However, my understanding is that perceived fatigue is feeling tired, physiological fatigue is when your muscles can't do any more work.

If you imagine a healthy person lifting a heavy weight repetitively until they can't perform another rep. They would experience physiological fatigue but not perceived fatigue.

 

[jimells]

If you imagine a healthy person lifting a heavy weight repetitively until they can't perform another rep. They would experience physiological fatigue but not perceived fatigue.

About 25 years ago I spent one winter working in a potato house. Potatoes are piled high in open-front bins. My job was to shovel the potatoes, by hand, into a hopper that fed the sorting and packing line. There were three of us doing this job; two of us shoveled while the third worker took a break by watching and adjusting the conveyor that was loading bulk potatoes into the trailer. We loaded a trailer a day - that's about 50,000 pounds, or 25 tons of potatoes, all shoveled by just three workers, so we each shoveled about 8 tons a day.

I definitely know something about experiencing physiological fatigue. I assert (without any real evidence ) that "perceived" fatigue is not a neurological signal that unconsciously tells muscles to stop working. It is easy to push muscles to the point of failure - doing a number of pushups demonstrates the concept.

This may not be a good comparison, but I'm sure most folks have heard tales of horses literally worked to death. I expect those horses also perceived fatigue before they collapsed.

 

[duncan]

Instead of creating the easily distorted or misused "perceived fatigue", why not simply qualify "fatigue" at the beginning? Asterik it. Qualify it once, then use it how you mean it to be used - and most of the world interprets it - through the rest of the narrative.

Otherwise, well... this is just asking for trouble.

 

[Seven7]

I just Had an 3h episode where I lost all consciousness. I didn't feel fatigue, It was like my brain fell sleep kind of feeling very specific in the head. I told hubby I don't wnat to go to bed so early he said go and just stretch in the bed but the numbness feeling took over my head and then I was gone completely. I felt a bit of burning in the legs as I went up the stairs. I did take the beta blocker and the midro but that did not stop the episode this time.

I feel like when a leg falls sleep in the head. And the part where hair grows feels like prikly as if ants are crawling.

My point I lost all control of body and the feeling per say ( this time) was not fatigue at all. More as if a chemical spilled in my head.

 

[Scarecrow]

Isn't it 'perceived' simply because it can't be objectively measured?