Rapid fatigability or a lower amount of available energy - the same thing or different?

[DokaGirl]

I don't know if this is any help, but I once heard that when a pwME "runs out of energy" it is much akin to what a marathon runner experiences when they "hit the wall" ... except of course for a pwME it is an endless succession of such experiences. Totally and utterly f****d, nothing left inside, and feeling truly ghastly. When the science of ME/CFS is properly understood, it would not surprise me if that analogy doesn't have an element of truth to it.

Yes, the rapid fatigability does feel like hitting a wall. I just have to stop. I'm basically forced to stop by burning muscles, OI flaring up, and other symptoms. If I try to continue, the symptoms increase.

 

[Subtropical Island]

Reading this thread I found some of them I only agreed with parts of (or I felt that there was extra stuff in there that made it harder to see the main point) so here they are, edited down to something I’d agree with/want to say:

So Z can manage maybe an hour for coffee and chat, at the right time of day. There is obvious dropping off towards the end of the hour, cognitively and physically. This was especially noticeable when we were doing the PIP process! She would not be able to do this everyday.

My daughter can, some weeks, manage an outing of a couple of hours, or having a friend round. This is preceded and followed by a few days of doing very little physically, other than getting up/dressed/eating etc. Her cognitive processing is always significantly impaired. There is no way she can understand the AS level Maths that she passed with an A grade, nearly a decade ago.

I do like the battery analogy. Most people understand this from phones/laptops etc in that they run down and then neeed recharging. But with age or an Apple product, in time it cannot fully recharge. My daughter manages a tiny percentage of the activity that she used to be able to do, pre ME.

I always steer well clear of the word 'energy' when talking to people about ME. Because people (when trying to understand another's experience) always try to relate whats being said to what they already know, & when i was healthy i used to sometimes say "goodness me i am so tired i've got no energy at all today".

What i meant was that i felt flat & sluggish, like it was a big effort to peel my arse off the settee & do things, but i was still entirely capable of doing whatever i needed/wanted to, i just felt lethargic....
So my sense of how much energy i had was that i didnt have much, but i was still pretty much unlimited in what i was actually able to do.

So if i mention 'lack of energy' or 'running out of energy' to people, they mostly say "oh yes i know what that's like", but they are relating it to their own experiences of feeling as i described.

And that is NOTHING like what i'm experiencing! ... I'd be thrilled to only feel like that! When i say i feel too ill/weak to stand up, it's because when i try to, because i need to, i cant. ...in my experience people always think it means "feeling knackered but still totally capable if you push yourself". And thats not what i want them to think, because it's grossly inaccurate,

In my opinion whatever you say healthies will say me too whether the word is fatigue, energy or ill.

i think there is definitely something about energy but it is so closely tied up to levels of symptoms pain, fluish feeling headache sore throat or whatever it is.

I mostly ignored it for years, but I had mild chronic fatigue since my teens. I could still do most normal things and was active, but I was tired all the time. Never stopped me from being relentless when playing sports or doing hard work.
...
Absolutely nothing to do with the ME exhaustion, which is more similar to the kind that comes from the flu with a fever, when it's more apt to talk of weakness, of struggling with minimal exertion. It's a much more complex concept than normal fatigue, way more layers and depth.

To an external observer it's impossible to see the difference, but they are nothing alike.
...

I know what being tired all the time is. It's absolutely nothing like ME. This is completely above and beyond it and is better described as sick.

Excellent description @Invisible Woman - that is exactly how I feel. Like a more under powered engine than needed for many ordinary tasks. With extraordinary demands I can start the task, but my power doesn't endure, and I am forced to stop because my power runs out.
...
Thank you @ Andy for posing this question.
...
Very obviously, this is a difficult concept to get across to healthy people. I have known people who are healthy for all intents and purposes , who are also quite sedentary. They don't see any difference between themselves and someone with ME who needs to rest a lot. Even though very sedentary, taking on tasks above their usual activity level will not tire them out. More extraordinary tasks might but not run of the mill things like shopping and cleaning the house.

That is my experience of the rapid fatigability when exercising. The power we expect to be there is not there at all and any effort to push harder is also associated with a rapid increase in pain (which diminishes quickly if I back off).
...

For me, physical exertion can lead to cognitive symptoms, but cognitive exertion does not lead to increased fatigability or weakness of my muscles.
...

That is not my experience at all. I like exercising. For me, riding up a steep hill is fun, but this is something I can no longer do without an electric bike. On the 2 day CPET, my heart rate peaked at 202BPM on the first day and 194BPM the second day - my problem is not a lack of pre-motor cortex drive! Overall I had above average VO2Max for my age, though by no means athletic. (Absolute VO2 of around 3.5L/min)

Personally: I find that I can be very bad at knowing when I’m getting tired. Perhaps I’ve always adjusted my perception of being tired against what I expect of myself in activity, and my expectations no longer match my physical ability.

The single most effective intervention I have found my illness is to try various strategies for readjusting my own expectations, to build in stops in activity to give me time to notice if I am in pain (or otherwise drained by the activity), and to preemptively moderate my activity. Learning to do so has given me a great deal more of my functional life back (because I focus on being efficient with what I have, and flexible in goals).

So, answering @Andy’s question:
I avoid approaching fatiguability as much as I practically can. It’s a bad sign.
And it has changed: When newly ill, and for a good 5yrs after that, I was able to perform physically as well as most fit and active healthies - but then I paid for it 24hrs later. Now, more like 6-8yrs in (I forget), I am more easily fatigued, but I might be able to put that down to lack of activity and fitness compared to my past. My past lifetime of health and fitness lasted me an inordinate number of years of initial illness but I believe I’m running out of that now. I’m sad about it but it might help me to avoid crashes if I can feel tired when pushing past my daily allocation of activity.
So, always had a limit, a quota in this illness. More recently become rapidly fatiguable (as well as a the quota, which I can eek out through a careful day). Hard to know if that’s me being aware, a change in my own physiology, or what. Not going to guess.

I have liked the original spoon theory because it seemed to highlight the tangible limits, that it’s not about stretching out a spoon or looking at it differently. Once it’s gone, it’s gone, you don’t get extras (no matter how ‘good’ you were).

I get the flu (including ‘tummy bug’). Just without an infection. I suppose we could theorise about it being an immune response. But I don’t want to waste more time theorising. (I’m interested in 1) Research by those who understand and practise the scientific method or 2) personal experiences but not a mix-up.)

The exception (for me) to the hard, impassable, limit .... or the increasingly dense symptom load (sometimes it’s not a hard wall) ... is adrenalin (or whatever cocktail my body produces) = I do find that I can do more when it’s an emergency. But when that is over I am tired and then 24hrs after the start of the extra activity I’m quite predictably ill (not depressed, not unmotivated, not feeling a bit under the weather - I’m sick and incapacitated).

I have a quota. Sometimes it aggregates over a week, but at some point, the pain and illness will arrive and take their toll.

 

[MeSci]

Just posting this quickly before I lose my thread: the results of my step-exercise test in 1995 for the Open University - thought it might contain something of interest. (I developed ME that year.)

 

[Daisybell]

I can still recall pre-illness days of waking up and feeling like I could jump out of bed and heading straight off for a run...
No way do I have that feeling of ‘energy’ ever now. I also fatigue much more quickly. The fatigue affects everything - physical and mental. If I try to push through physically, then I will get muscle cramps and a feeling of overwhelming exhaustion. Also possibly I will become tachycardic. It now takes days to recover or weeks rather than recovering after a good night’s sleep.

The more I push the boundary of what feels ok, the more I feel that I dont have available ‘energy’. Everything gets affected - circulation, digestion, cognition, and the ability to do physical things. I don’t think I could keep pushing through that although adrenalin will carry me through for a short time. I will get very cold hands and feet, facial flushing alternating with being very pale....

 

[Blueskytoo]

Interesting topic and fascinating reading everyone’s experiences.

I have severe ME and was moderate for the first four years of my illness. I’ve now been ill for 12 years.

So, once my meds have kicked in for the day, as long as I do as little as possible I actually don’t feel that unwell. I also have fibromyalgia, arthritis in my hips and POTS, so sometimes telling what’s ME and what’s POTS and what’s fibro can be a bit hard but generally although I’m stiff and creaky and ache quite a lot, I don’t feel too bad. At the moment I’m in a slightly better place after my normal winter 3 month relapse, which isn’t to say I have any more function than usual but that after three months of feeling like I got hit by a bus and then run over by the juggernaut behind it, improvement is relative and any is welcome! Even now, though, if I attempt anything more strenuous than making a cup of coffee and sometimes even that is enough, I will start to get symptoms including getting sweaty and clammy, feeling incredibly ill and running out of whatever we think energy is. Lying down will alleviate a lot of the “ill” feeling, but it doesn’t increase my energy levels. Once I’ve used up whatever it is, it’s gone and it’s gone for at least a couple of days. I can do things like lift a heavy object, like a basket of wet washing, for example, but I can only do it once and I will pay for it the next day, or the day after. I don’t feel tired any more now than I did when I was well, although my sleep is bad at the moment due to menopause so I am currently more tired than usual, but that is due to lack of sleep, not anything else. Previous to menopause I slept well, a good ten hours a night, yet still woke up feeling unrefreshed. But not tired.

I don’t suffer from fatigue, I suffer from what appears to me to be a lower level of “standing” energy, and a much higher level of output - as in, activities that I wouldn’t have even thought about when I was well, like showering or getting out of the bath or putting on my coat to go out, now use up an enormous amount of my daily energy allowance.

I think of it like a bank account - I have a daily amount that goes into my account. If I don’t spend anything (don’t do anything, spend the day in bed reading or doing very little) I get a tiny amount of interest on my balance which I can slowly use to build a little reserve. If I do spend something on day to day activities like going to the loo or moving around the house or making a hot drink, that interest is gone and the balance goes down and, as usually the expenditure is more than the next daily amount going in, it takes a few days to get my balance back up to where it should be, and the interest is used, not to build up a reserve, but to get the balance back to normal.

If I spend more than I can afford to, for example having a shower, or needing to leave the house for something, or dealing with a family issue, (which happens more than I’d like but tend to be things I can’t ignore and consequently have to spend out on) then my balance dips into the red, into the overdraft. When this happens it takes me much, much longer, weeks, often, if not months, to build my balance back up to its normal level, and I not only have lost all my normal balance but the interest is being used to pay off the overdraft too. And in the meantime, because of the fact that I have to eat and go to the loo and at least attempt to keep myself clean, I’m still using up some of that reduced balance in just living so it’s usually well under where it should be and I rarely if ever manage to save up any decent interest. So I’m always living, if not at the full stretch of my overdraft, or in the red, with at the very least a permanent deficit because, just from living, I’m spending money (or energy) I don’t actually have.

I’ve found that, for me at least, that’s the most helpful analogy I’ve ben able to come up with to explain how I feel and the limitations I have - spoons don’t really work for me and the battery one doesn’t deal with the “less than nothing” level of whatever-it-is that pwME can struggle with. Batteries can only be flat, they can’t be less than that.

 

[JemPD]

When we have flu I actually think there is a block to access to energy usage in muscles in that if you were asked to lift something very heavy when in the middle of flu your arms simply would not work. But again I think that is a neural inhibition probably due to gamma interferon in the muscles.

Is this testable/has it been looked at?
One thing i find so remarkable is how when i get a bug - flu/infection etc i feel identical to an ME crash. The crash has more symptoms overlaid on top - eg marked cognitive difficulties, but otherwise in terms of experience they are exactly the same.

Pls excuse my ignorance but would it be the same (gamma interferon in muscles) when any immune response is triggered - ie when one gets the AZ vaccine? I rested for several days previous to my jab & getting it, because of the place being so close was within my limits, so I'm certain my response to it had no aspect of PEM. But i was amazed by how totally the same it felt to an ME crash, the weakness the all over pain, the dizziness & nausea, chills/sweating etc etc, the only difference was that I actually had a 38d fever instead of merely having the sensation of having one.

What struck me, as it always does in every crash, was the lack of power in my muscles, i hadnt the strength to tear open the paper wrapper on a panadol. And i was unable to heave myself off the loo - i went to use the grab rails but because i only had use of one arm (jab arm turned into an agonising lump of wood hanging down my side) & both legs, instead of 2 arms & legs i just could lift myself off. I was extremely motivated to do so as you can imagine lol and shocked at being unable..... As i am always shocked at not being able to lift the milk bottle during a crash.

 

[JemPD]

One I think remarkable aspect of my fatigueability is that mental exertion can cause widespread weakness and fatigue in the rest of the body so that it visible affects my gait and walking speed.

And similarly, after a walk I'm not very talkative because my brain is affected as well. Presumably by the orthostatic stress.

Yes, this, i always find the cross over remarkable too. Sitting reading for too long & my legs stop working properly - coordination goes very wonky.

 

[Barry]

Perhaps there is nothing wrong with our energy system but there is something else, a bodily signal that gives us terribly symptoms whenever we try to do something.

As an analogy, take someone with severe back pain. He might not have an energy problem to take out the weed in his garden, but the back pain prevents him from doing so.

Yes, I think @Jonathan Edwards has touched on this, probably others.

To my mind an "energy system" would involve everything involved in energy delivery, including all and any control loops and related feedback signals. Messed up control signals would be just as valid a reason for a messed up energy system as anything else. Your central heating may not be working because the boiler is broken - no energy available, but it could just as easily be messed up because the thermostat is broken, effectively lying and saying the house is warm enough when it is actually freezing cold. And of course a boiler has its own control loops inside it, so might not be working because some of its own internal signalling is broken.

Anything that relies on control strategies, be they open or closed loop, are only ever as good as the control signals they rely on.

And of course at the top level, there are control signals that impinge on our consciousness, like pain, fatigue etc. If that signalling screws up, and a cut finger feels like you've just had your arm lopped off, then you are going to behave as if your arm has been lopped off. Similarly, if walking upstairs provoked seriously screwed up feedback signals that made it feel like you've just run two marathons, you will have no choice but to believe it. We only know what the signals tell us, with no way to tell if they are lying to us or not.

But of course if some part of the energy chain has a faulty control loop, with dodgy signalling telling it it is providing much more energy to your body than it actually is, then the result is still too little energy being made available, albeit due to faulty signalling in this example. Like putting your foot to the floor on your car's accelerator, but the signal it generates into the engine management being messed up, and telling it the accelerator is only a quarter way down. You will get far less power than needed, but it's due to dodgy signalling, rather than the energy delivery capability itself.

 

[Creekside]

That sounds more like a problem with motivation to me.

Yes, I think it's the neurons involved in motivation not functioning normally. There seems to be some understanding of the parts of the brain involved in motivation, so it's not a complete mystery. I'd study that research material and try to figure out why my ME is affecting motivation ... but I lack the motivation to do that.

 

[Creekside]

Have there been a clear clinical answer to the question: "Do PWME have lower ATP production and/or reserves?" I've seen some studies saying yes, and others saying no, but I haven't seen one yet that definitively answers it. However, I think the question should be "Do all PWME have lower ATP production and/or reserves?", since if there is an ATP problem, it could be a downstream effect of ME for some PWME but not all.

 

[Ravn]

But do people here feel that the best explanation is simply that we have a reduced store of energy, or that our ability to replenish the store is diminished, or both?

"Available energy" versus "reduced store of energy":

I think if you want to come up with a vaguely scientifically defensible explanation it's probably safer to emphasise the availability/rate of production line than the energy storage one. We know even less about the latter than the former.

Reduced availability in the sense of not being able to make or deliver energy, for whatever reason, at the rate required for a specific task is something for which we have the various studies pointing at possible underlying mechanisms (early switch to anaerobic metabolism, mitochondria already working at full rate at rest and unable to respond to increase in demand, increased metabolic byproducts, etc.). The exact problem/s is/are far from settled but it looks pretty certain that something isn't working properly.

Reduced energy storage seems to have barely been looked at in ME (based on a very cursory google search). Which is surprising given that glycogen depletion has long been linked with fatigue in healthy people. For example:
https://www.gssiweb.org/sports-science-exchange/article/sse-155-metabolic-factors-in-fatigue

Cort mentions in passing in this 2019 blog that Ron Tompkins is looking into glycogen storage in muscles (though it doesn't seem to include the rate of glycogen depletion and/or replenishment which could be equally important factors):
https://www.healthrising.org/blog/2...s-energy-production-chronic-fatigue-syndrome/

So that was about actual cellular energy goings-on. The sensation of having or lacking energy is a different matter again. One, it can cover a lot of sins from tiredness to weakness to fading and more. Two, it may or may not be linked to the actual amount of cellular energy available. I don't think anybody really knows. So you can make analogies of the 'to me it feels like...' type but not the 'it is like...' type. And once you're into 'it feels like...' analogies you're risking misinterpretation. Everybody has had the sensation of lacking energy and they'll interpret our reports through their experience which usually includes being able to force themselves to do more regardless if necessary, but it sure doesn't include PEM later.

In practice, talking to the 'average' non-sciencey person, I find the dodgy cellphone battery analogy is the most effective to get across at least a hint of the impact ME has on what I can or can't do. It's still mostly a 'it feels like...' analogy and you wouldn't want to push any claims of scientific accuracy too far but at least it limits the scope for it's all in your head misinterpretations. Most people view their dodgy phone batteries as faulty rather than as lazy or unmotivated.

My exact script varies but goes roughly like this:

Battery never charges fully. Drains too quickly. Puts phone into battery saver mode disabling non-essential functions. If not recharged phone ceases to work completely. No fast charger available. Standard slow charger (mild). Solar charger (moderate). Solar charger when it's raining (severe). Solar charger at night (very severe). Often need to use phone for essential function when only minimally recharged so it's back into battery saver mode or failure ever sooner until there is opportunity to recharge to minimal maximum battery is still capable of.

 

[Wonko]

Regarding 'energy'; a couple of examples of what has happened to me.

I can feel as if I have plenty, even a excess, of energy, but when trying to use it, in say walking, it's as if I am trying to pipe it through a leaky pipe (nothing like that I'm just trying to get an idea/sensation across). I can be exerting enough energy but almost none of it goes into forward motion of my legs. It's as if it's going 'everywhere' else but where I am telling it to. Backing up. And the more 'force' I exert, the worse it seems to get - so I can be feeling like I am using enough force to push a lorry (I have done this so I know of what...lol) and barely moving, with an ever increasing feedback from my legs - which is 'uncomfortable'.

I assume this is related to what others describe as wading through treacle.

On other occasions I've been 'okay' - not well enough to be out but prepared to pay the price later - and then with every step I can feel 'energy'/'strength'/whatever draining out, through my feet. It is a very clear sensation of that. Stopping doesn't help, the drain continues - at that point the only thing I can do is abandon whatever was presumably urgent enough to get me to go out when I wasn't up to it, and try and get home. This has been known to take a 'while', a battle to get from bench to bench on the way home - hence why on occasion on here I've had rants about them removing all the damn benches here.

There was something else, related but not an example per say - but in typing the above it's gone.

 

[Trish]

So to state from the start, I don't have the answer to the question in the thread title, but that's why I've started the thread.

I've been mulling over how I might present ME on a basic level to people who don't understand it and rather than launch into PEM from the start, I thought emphasising the reduced level of available energy would be an easier concept for people to grasp (and that could then lead more naturally on to the consequences of overexertion). But do people here feel that the best explanation is simply that we have a reduced store of energy, or that our ability to replenish the store is diminished, or both?

While I would love to have scientific proof for any of this then that would be great but I'm as interested in whether this matches the experiences of people here.

I'm sorry I haven't managed to keep up with all the discussion on this thread, so I may be repeating what others have said.

I think before you can provide an answer to your question, you need to clarify the question. Do you want to tell the person about the cause, or the effect of ME?

If we start with the assumption that your purpose is to convey what it's like living with ME - what ME is from the patient's perspective - then I think you need to focus on symptoms and the effects of activity on those symptoms and the limitations it places on your ability to live a 'normal' life.

So you could say, as i have done elsewhere on the forum, that 'the more you do the sicker you get.' If you want a longer description, you could talk about how the muscles feel during and after, for example, having a shower, or going for a short walk. In other words, paint a picture for them of what it feels like and the limitations it imposes, including describing PEM.

If we try to describe it in terms like available energy, or metaphors like faulty batteries, I think it can be counterproductive. We don't know the science, so we can quickly get into hot water if we try to talk biologically about broken energy systems, and the battery analogy takes too much explanation to make it a close enough parallel to what I experience, and leaves out the pain, OI, nausea, headaches etc.that are part of the package.

 

[Mij]

How is it that some of us have more 'available energy' on some days and not so much on others?

Why is it that sometimes when I start out on my walks my legs are not wanting to hold me up and wobbly? It's like I have MS legs. Then as I get going, my gait becomes smoother and I'm able to walk ok with full speed? This occurred the other evening and on other occasions. This feels like an immunological response. My shins were burning, but it was tolerable.

I got home after 40 minutes and felt almost normal, yet when I started out I almost came right back home after 4 minutes.

 

[Snow Leopard]

But of course if some part of the energy chain has a faulty control loop, with dodgy signalling telling it it is providing much more energy to your body than it actually is, then the result is still too little energy being made available, albeit due to faulty signalling in this example.

But the body doesn't have such a system. There is no system of body-wide energy homeostasis, there is only peripheral signals telling the brain not all is well in some particular part of the body.

The closest to such a system is the blood glucose regulation system (which is relatively simple and hormonally driven - insulin, glucagon, cortisol) and the cardiovascular system which does rely on learned optimisation in terms of ventilation, heart rate drive and blood pressure for a given level of drive, but there are still several feedback loops involved - heart rate lags ventilatory rate, for example.

 

[Barry]

But the body doesn't have such a system. There is no system of body-wide energy homeostasis, there is only peripheral signals telling the brain not all is well in some particular part of the body.

The closest to such a system is the blood glucose regulation system (which is relatively simple and hormonally driven - insulin, glucagon, cortisol) and the cardiovascular system which does rely on learned optimisation in terms of ventilation, heart rate drive and blood pressure for a given level of drive, but there are still several feedback loops involved - heart rate lags ventilatory rate, for example.

Not sure if we are at cross purposes here? Never said (or never meant to say) I thought there was just one big control loop, all on its own. That would be a non starter for something this complex I imagine, with so many sub-components each needing their own control - at least in the world of process control which I am more familiar with. I imagined there would be quite a lot of control loops, potentially including cascaded control loops (control loops nested inside other control loops).

Another example of closed loop control is presumably the thyroid.

 

[borko2100]

I have both. I feel like I have no energy to do things and when I try to do them my muscles and cardiovascular system give out very quickly. To give an analogy, 5 minutes of light biking feels like what hours of intense biking would feel to a normal person.

When my illness was better I was hoping that maybe it was deconditioning so I tried to increase my endurance by doing a bit of cardio every day. After weeks of doing this I had made zero progress, my endurance and cardiovascular condition was nearly the same as when I had started. This made me realize that it wasn't deconditioning (and it made no sense that it was considering I was young and had healthy levels of muscle and body fat), but rather something very wrong with the energy producing systems in my body (I also ruled out heart conditions).

 

[Florence]

This isn't original, but when I want to describe my energy problems to a 'lay' person I say it feels like having the flu all the time. In other words your body is screaming at you to rest, and if for some reason you don't, you end up feeling ten times worse.

 

[alex3619]

Yes, the rapid fatigability does feel like hitting a wall. I just have to stop. I'm basically forced to stop by burning muscles, OI flaring up, and other symptoms. If I try to continue, the symptoms increase.

About two and a half decades ago I had my last attempt at aerobic fitness. In just a week I started my third or so slow jog, after a slow walk warmup, and hit a wall in seconds. There was NOTHING there. No energy reserve. No way to push past it. I was reduced to a slow walking shuffle. I did not "recover" for about six months. Having to walk super slow is not fun.