The 12th Invest in ME Conference, Part 1
OverTheHills presents the first article in a series of three about the recent 12th Invest In ME international Conference (IIMEC12) in London.
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Tiredness Vs Fatigue - Are they being confused, and is that the big problem?

Discussion in 'General ME/CFS Discussion' started by Barry53, May 26, 2017.

  1. Barry53

    Barry53 Senior Member

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    @Jonathan Edwards: If you wouldn't mind, I'd be grateful for your thoughts on this please.

    I'm not qualified to comment from a medical perspective, but from my own personal experience, tiredness and fatigue, though they can have a strong correlation, do not seem to me to be the same thing at all.

    As I see it, tiredness is when your brain is telling you you need to sleep. Of course fatigue can, and typically is, a common trigger for your brain to do this - but not the only trigger surely. I commented on this in ...

    Incidence of ME/cfs in a large prospective cohort of U.S, post #7

    ... that there were periods many years ago when I used to suffer from quite severe tiredness, but not fatigue.

    I cannot help wondering if this is where a lot of confusion lies. I notice that quite a lot of research talks about the brain signalling fatigue, but how do researchers actually know if it is fatigue or tiredness that is being signalled? Is there a definitive objective test for this? Or is it back to patient questionnaires again?

    If it is questionnaire based, is a subject, or even researcher, necessarily going to know if the subject is really feeling very tired? ... or very fatigued? The two things can be ever so difficult to discriminate between. Indeed I suspect many patients (maybe researchers?) do not realise they are different. So are these researchers really researching people with fatigue at all, or potentially people with a condition that makes them feel extremely tired, even if they are not actually fatigued? And if their problem is tiredness rather than fatigue, but everyone involved in such trials believes they are researching fatigue ... no wonder it's all such a mess.

    I'm guessing that fatigue is very much about lack of useful energy being available where it is needed. No matter what a person's brain might tell them to do, they cannot defy the laws of physics and drum up energy that is not there. This feels to me the situation for ME sufferers.

    And I'm similarly guessing that tiredness is when your brain is telling you to sleep, irrespective of what useful energy your body may, or may not, have available. And maybe there are some conditions where a person's brain is insisting they feel tired, even if there is no apparent need. I wonder if this is where some misdiagnosed cases of ME occur.

    I mean - if someone feels very tired, but a questionnaire asks if the feel very fatigued, are they going to say Yes or No? And if some time later, they feel much less tired, and they are asked if they feel more/less/same fatigue as before, they are surely likely to say they feel less fatigued. Whereas in such a case, they would be really be less tired, but neither the subject or the researchers would know any different.

    Is asking about fatigue, actually a leading question that assumes fatigue, when it is not really known if the problem is tiredness or fatigue?

    And is the distinction between tiredness versus fatigue properly recognised?
     
    Last edited: May 26, 2017
  2. Sushi

    Sushi Senior Member Albuquerque

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    But, for some of us, our brain never signals us to sleep--at least in terms of sleepiness. I'm not sure I see the difference between tiredness and fatigue--could you say more? If I do anything I feel tired, but I have no inclination or ability to sleep. I'd use tiredness and fatigue interchangeably but would differentiate sleepiness.
     
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  3. Old Bones

    Old Bones Senior Member

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    Here's one researcher's explanation:

    Fatigued or just tired? There is a difference


    http://www.reuters.com/article/us-fatigued-tired-s-idUSCOL75594120070207

    "(Reuters Health) - Being tired is not the same as being fatigued or exhausted, and the difference matters, according to a researcher from Canada who has spent years investigating fatigue in various populations.

    'It's important to recognize the difference between tiredness and fatigue, because fatigue is a marker that the body is not able to keep up,' said Dr. Karin Olson, with the faculty of nursing at the University of Alberta.

    Olson has studied fatigue in cancer patients, people diagnosed with chronic fatigue syndrome and depression, as well as shift workers and athletes.

    Based her observations, Olson created new definitions for tiredness, fatigue and exhaustion that she believes represent various points on an energy continuum.

    People who are tired, Olson explained, still have a fair bit of energy but are apt to feel forgetful and impatient and experience muscle weakness following work, which is often alleviated by rest.

    People who are fatigued, on the other hand, experience difficulty concentrating, anxiety, a gradual decrease in stamina, difficulty sleeping, and increased sensitivity to light.

    People who suffer from exhaustion, Olson has observed, report frank confusion that resembles delirium, emotional numbness, sudden loss of energy, difficulty in staying awake as well as in sleeping and complete social withdrawal. . . .

    Failure to recognize the difference between tiredness, fatigue and exhaustion could lead to inappropriate approaches to combat the problem, which could make matters worse. For example, Olson has some evidence that while exercise may relieve tiredness, it may decrease the ability to adapt in people who are suffering from fatigue or exhaustion."
     
  4. Dechi

    Dechi Senior Member

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    Funny, in french there is only one word for both fatigue and tiredness, so there is no way to distinguish between the two.

    From what I understand fatigue is an ongoing state and tiredness is punctual, ie it has a start and an end. You can be fatigued for months and years, but you will only be tired for a few hours or until you rest.
     
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  5. trishrhymes

    trishrhymes Senior Member

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    I think I experience them as two different things. I think I would say I am tired when I am sleep deprived and if I rest I am likely to fall asleep for a bit, whereas I am fatigued if my muscles feel unable to function and are weak and aching.

    Before I had ME , I'd say I was tired at the end of the day and was ready to sleep, or hadn't had enough sleep the previous night. Whereas I was briefly fatigued after playing sport or other sustained or vigorous exercise.

    With ME the fatigue never goes away, and worsening after activity is unnaturally heavy and prolonged. Tiredness is only a problem when I've slept badly.

    Post exertional malaise, for me kicks in some hours after I tip over my physical activity threshold and is not just increased fatigue, It's more like getting flu with weakness, dizziness, nausea, headaches, on top of an enhanced version of fatigue and muscle pain, and brain fog. When I have PEM all I can do is lie in bed in a fog, hoping not to vomit. Delightful (not).

    I think a lot of the misdiagnosis by the likes of Esther Crawley is because she doesn't distinguish between the two, so ends up diagnosing lots of sleep deprived kids as CFS, and then 'cures' them with sleep hygiene. She also seems to misunderstand PEM as simply feeling more than usually fatigued after exercise.
     
    Last edited: May 27, 2017
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  6. arewenearlythereyet

    arewenearlythereyet Senior Member

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    I think the key for me that denotes exhaustion or PEM is the cognitive symptoms of confusion short term memory loss and sound and light intolerance. I get a bunch of other ones such as waves of nausea, splitting headache, joint pain and obviously lack of energy to do anything but sit or lie down. I only class it as PEM if I have drops in energy with the cognitive stuff. There are times when I have drops in energy which mean I sit/ lie around for a day or two, but cognitively I am relatively ok. This is just regular fatigue as oppose to PEM in my little world of anal record keeping.
     
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  7. arewenearlythereyet

    arewenearlythereyet Senior Member

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    Just for the record I record most things but do not take a mirror to my anus....just thought it best to clarify :jaw-drop:
     
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  8. Barry53

    Barry53 Senior Member

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    Exactly where I was aiming for.
    Again, exactly what I said in my original post. If you look at my other post I linked to, I have experienced considerable tiredness, but without fatigue ... and please note that in that post I make it very clear I did not, and do not, consider that to have been ME.

    I think the two terms, tiredness and fatigue, are so terribly easily conflated that they frequently are, often completely innocently and by patients and scientists alike, although in the latter case it is not always so innocently done I fear.
     
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  9. Barry53

    Barry53 Senior Member

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    Having just posted, I then found myself browsing in reverse order (from the bottom up!). This post really made me wonder what I was going to read next :rofl::eek:
     
  10. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    As all the posts illustrate all these terms seem to have a range of meanings that overlap in some ways and not others. I do not think there are official medical definitions and I doubt that official dictionary definitions help much either.

    My thought is that the PEM term captures something - the 'malaise' word implies an unpleasant feeling, or at least a negative feeling. That seems to me the crux of the fatigue of ME/CFS. No that I am no longer 25 I find I can mow my lawn with my preferred manual push mower for about fifteen minutes at a time and am then 'fatigued'. I am not tired but I need a rest. I can do more mowing after a while. I think this is pretty much the sort of sense of fatigue that one would associated with an army camp - in which case it might be brought on by four hours hiking with an eighty pound backpack. After a break for food a good soldier can then do another four hours.

    That sort of 'normal' fatigue clearly still does not capture the symptom of ME/CFS but I suspect it is much closer than sleepiness or tiredness.

    My own suspicion is that this is not actually to do with energy availability. If I needed to finish mowing the lawn before catching a plane I would simply carry on. My muscles work do the job. In a war situation the soldier would march for eight hours non stop. What I think causes fatigue is neural signals that come as a warning that continued activity is likely to produce tissue damage, not lack of metabolic source of energy. What happens if people push themselves with fatigue is that they develop tendinitis or muscle tissue breakdown. I think fatigue is the body's mechanism for stopping before those become a risk.

    This sort of explanation for me fits much better with the aversion to light and sound PWME experience - it is all about danger signals that tell the body to shut down activities at a reflex level.
     
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  11. Barry53

    Barry53 Senior Member

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    Again to be clear, I am not medically qualified, so what I say here is just my own engineer-oriented perceptions.

    My guess is that when you say you feel tired, what you are actually feeling is completely fatigued ... your body has run out of usable energy, and nothing but nothing can get your body through that until you achieve some kind of energy recovery, small though that may end up being. And maybe your issues are compounded by the fact your fatigue is not doing what it would do in a healthy person, and is not triggering you to feel tired. So you would be totally exhausted (i.e. usable energy all gone), but unable to react in a way that achieves energy recovery.

    Edit: @Jonathan Edwards posted before I posted this, and needless to say Jonathan's post should be the reference.
     
  12. bertiedog

    bertiedog Senior Member

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    That's a brilliant description of what happens to me when I have used up all my physical energy. It happened a couple of days ago when I had been busy in my garden and I had gone to look around my son't new house which meant standing for 30 minutes. There was nothing much there in the afternoon when I wanted to walk my dog. I really wanted to go out an enjoy my usual walk but my body wasn't having any of it. I really suffered that evening with severe leg pain and dizziness and a nasty migraine the next day.

    Pam
     
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  13. Barry53

    Barry53 Senior Member

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    Exactly my thinking, and why I wanted to air this in PR. To me it feels quite key.
     
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  14. slysaint

    slysaint Senior Member

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    Well the word 'fatigue' in english does come from the french fatiguer whereas the root of tired is Old English tyrian is to fail, tire.

    Someone researched this
    http://www.reuters.com/article/us-fatigued-tired-s-idUSCOL75594120070207

    "
    Fatigued or just tired? There is a difference
    By Megan Rauscher | NEW YORK
    NEW YORK (Reuters Health) - Being tired is not the same as being fatigued or exhausted, and the difference matters, according to a researcher from Canada who has spent years investigating fatigue in various populations.

    "It's important to recognize the difference between tiredness and fatigue, because fatigue is a marker that the body is not able to keep up," said Dr. Karin Olson, with the faculty of nursing at the University of Alberta. "The onset of the manifestations of fatigue, particularly if these are not normal states for you, should be taken seriously."
     
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  15. Murph

    Murph :)

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    This makes a lot of sense to me. The body is sensing things when we exercise that make it want that exercise to stop. I suggest endothelial sheer stress or lower ATP availability as possible triggers for the neural(/mitochondrial) signals.

    I also suggest that if the body is catabolising muscle to try to provide energy (as Naviaux found in men), and you instead take amino acids, you may be able to provide some of the energy signals the body needs and some of the conditions that perpetuate the fatigue state signals can be short-circuited.
     
  16. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    It may be worth considering what Mike Murphy said at the last IiME conference. He thought that blaming mitochondria for energy deficits in ME made no real sense but what did make sense was mitochondria playing a signalling role - crying out for help via cytokines or intracellular kinases maybe.
     
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  17. Barry53

    Barry53 Senior Member

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    Is this saying that it could be the cells themselves that are getting confused about what energy levels might be available to them?
     
  18. Aurator

    Aurator Senior Member

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    The question looks more like a linguistic than a scientific one to me. As such, I don't think you'll ever get a definitive answer to it.
     
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  19. Barry53

    Barry53 Senior Member

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    I strongly believe the opposite - I don't think it is linguistic at all. My wife has ME, and I'm very familiar with her symptoms. She experiences real fatigue, PEM etc. I used to get acutely tired, even falling asleep at work once, but never really fatigued. I can see both sides.

    When talking to my wife earlier she said, yes she can still remember what it is like to feel tired, but mostly she feels utterly drained, but often cannot sleep. And she said that she only really feels tired these days if she gets a bad virus. Without any prompting by me, she reckons that her ME is fatigue but not tiredness.

    And I suspect that because it is so hard to definitively discriminate between them, that so many subjective questionnaire-based research might be getting completely the wrong end of the stick.
     
    Last edited: May 27, 2017
  20. arewenearlythereyet

    arewenearlythereyet Senior Member

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    I agree I think the issue here seems to be one of feedback. I think it's been proven that the mitochondria are fully functional in people with CFS/ME once the mysterious blocking agent is removed?

    If the mitochondria have switched to producing ATP from fatty acid and amino acid etc then does this mean that the muscles glycogen stores are also defunct? It's probably not an either or thing I'm guessing more an efficiency variance?

    When glycogen stores are depleted in normal people they get fatigued, rest and then recover once they lay down more glycogen from the CHO in their diet up until a glycogen saturation point. This I belive has a feedback loop to insulin release etc. When fully topped up they can resume their activity and the fatigue goes away

    In our case the glycogen stores are presumably already mostly topped up since we haven't used them we just can't keep up with just fatty acid and amino acids we've got shunting around. hence there must be a shut down mechanism/feedback signal to encourage us to rest rather than start digesting muscle and fat tissue for energy ( starvation). I think with the amount of fat I've laid down that would be a long time, but the signal is quite persuasive.

    This would explain why PEM can occur after large burst of activity (aerobic or sudden heavy lifting etc) or equally if you keep on going for longer than your body can supply.

    I'm not sure if this gels with what's been said. It does make me wonder whether the cell danger response also causes the ongoing problems and that slowly other systems start getting confused as it goes on too long (endocrine, circulatory, digestion).

    Sorry this is a bit off topic and a bit rambley with a lot of assumptions....but it would be interesting to have a marker for glycogen depletion fatigue vs what we have if that is any different.
     
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