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Article: The Test: Part I of the Heart Rate Based Exercise Video Series with Dr. Klimas on ME-CFS Co

I do hope this kind of 'exercise' program will help me in the future. :D

At the moment, I'm sweating just from daily activities like making dinner, hanging laundry -- basically anything that keeps me mildly moving for more than about 10 mins.

I tried a very gentle yoga class with an understanding teacher. I wore my heart rate monitor and stayed below my AT. I crashed and PENE'd anyway. :( I suspect the getting to the class plus the yoga attempt was too much total even though I stayed below my AT. The most basic yoga on Wii Fit also crashed me, even though I stayed below my AT. I have to admit that it was discouraging.

I think the idea of exercising below our AT is a big plus for PWME. I believe many PWME will be able to maintain some degree of conditioning and muscle strength they wouldn't otherwise.

I suspect, based on my personal experience, that the technique is still a bit crude and may not account for some of the finer details of ME. For example, I wonder if total daily energy consumption isn't as (or more) important than AT at any given point in time. This may be a bigger issue for the more severely impaired or those who have been ill longer. Just a thought.....

This whole "exercise below your AT" is a great idea for PWMEs, but may not be appropriate for all of us, or at all points in our illness.

Agree with you on this. Multiple expenditures of energy, even though never reaching AT, can be accumulative and will take me to a crash eventually. This is the more common way I crash these days. I know better than to push the limits too much. It's the low level daily stuff that sneaks up on me. But, I think this therapy is worth a shot because I'll take every little bit of progress possible.
 
The reports from Tristen and Sickofcfs bear all the hallmarks of a mitochondrial disorder. The brain; heart; liver and skeletal muscles are all heavy users of ATP plus activities such as physical exercise or mental exertion and processes such as temperature regulation require a lot of energy. If we are not producing sufficient energy to meet all our needs then inevitably we will crash and can only rest until ATP levels are restored.

Think of it like the engine in your car (if you drive). At higher revs (heart rate) you are using a lot more energy, perhaps more than your compromised mitochondria can produce, but even at rest your engine is ticking over and using energy.

This neatly explains why overdoing any activity (physical; cognitive; temperature regulation) can exacerbate completely unrelated symptoms and underlies the 'energy envelope' theory and pacing approaches that have been succesfully used for many years to manage symptoms if not improve them.

The question is if, and to what extent, a programme of physical exercise may be able to enhance the capacity of your body to produce energy. It may do, if carefully controlled and supervised to avoid crashes, and over time allow for some improvement in function (but not a cure).

On the other hand there may be no effect or negative effects. The available energy is fixed at a reduced level and any structured exercise programme is energy used that could otherwise have been used for everyday tasks that are of more intrinsic value to people's capacities and well being (bearing in mind that most day to day tasks also involve the use of skeletal muscle).

We have rightly criticised the CBT/GET proponents for relying on subjective self reported improvements in physical activity and 'fatigue' without using objective measures such as actimeters which would unambiguously show whether overall activity levels increased or whether structured exercise merely displaced other everyday activities.

Surely the same criticisms apply here?

I mean, really? Are we going to get a paper at some stage entitled something like 'Moderate exercise improves subjective reporting of physical function in patients with chronic fatigue'? Will this do anything to enhance our knowledge and treatment of ME?

It would be nice if proposals for moderate exercise as a treatment for ME/CFS were placed within a coherent theoretical disease framework. At least then we might have a hypothetical justification for recommending it which could be tested.

At the moment the only rationale appears to be the usual 'exercise is good and avoids deconditioning'?

Due to the fact that we don't know for sure what is making us ill we also don't know whether exercise will help us, make us worse or even if tolerated is a useful use of our time and energy.

Don't get me wrong. I'm not saying that there is no value in exploring the conditions under which we may be able to tolerate exercise and the extent to which it might help (or not) with physical function.

There is potential here to learn more about the underlying pathology but not if we just focus on physical activity and not if we just focus on exercise as an end in itself or to justify a programme of 'pragmatic rehabilitation'.

We have had quite enough of that over the years.
 
It would be nice if proposals for moderate exercise as a treatment for ME/CFS were placed within a coherent theoretical disease framework. At least then we might have a hypothetical justification for recommending it which could be tested.

Don't get me wrong. I'm not saying that there is no value in exploring the conditions under which we may be able to tolerate exercise and the extent to which it might help (or not) with physical function.

I think there is a definite theoretical framework that is present but has not been fully fleshed out. The basic framework is 'people with ME/CFS have abnormally low aerobic capacity that prevents them from exercising in a normal fashion...if they are active only within that limited capacity they can improve muscle functioning and health. (Its questionable whether they can significantly improve their initial capacity....ie the maximum heart rate at which they can safely function - my guess is that some people can at least a bit and most cannot...but that's just a guess. )

The big theoretical question that is facing this model is what is limiting aerobic functioning and causing people with ME to move so quickly into anerobic energy production. Another question would be - as SickofCFS has pointed out - what other variable come into play? The person i talked to used immunovir to stop her chronic low grade fevers and then used the exercise program quite successfully. Is it necessary for some people to get their immune systems in better shape in order to benefit from the program. One paper suggested that low cortisol might be another kind of hurdle that needs to be surmounted for these types of programs to be effective. (Another paper suggested that it was not a hurdle). In any case ME is a complex disorder and I imagine the exercise program will work better in some (perhaps with less complex problems???) than others.

My guess is that heart rate will probably end up being a helpful but somewhat crude measure of the pathologies that occur during exertion.
 
The reports from Tristen and Sickofcfs bear all the hallmarks of a mitochondrial disorder. The brain; heart; liver and skeletal muscles are all heavy users of ATP plus activities such as physical exercise or mental exertion and processes such as temperature regulation require a lot of energy. If we are not producing sufficient energy to meet all our needs then inevitably we will crash and can only rest until ATP levels are restored.

Think of it like the engine in your car (if you drive). At higher revs (heart rate) you are using a lot more energy, perhaps more than your compromised mitochondria can produce, but even at rest your engine is ticking over and using energy.

This neatly explains why overdoing any activity (physical; cognitive; temperature regulation) can exacerbate completely unrelated symptoms and underlies the 'energy envelope' theory and pacing approaches that have been succesfully used for many years to manage symptoms if not improve them.

The question is if, and to what extent, a programme of physical exercise may be able to enhance the capacity of your body to produce energy. It may do, if carefully controlled and supervised to avoid crashes, and over time allow for some improvement in function (but not a cure).

On the other hand there may be no effect or negative effects. The available energy is fixed at a reduced level and any structured exercise programme is energy used that could otherwise have been used for everyday tasks that are of more intrinsic value to people's capacities and well being (bearing in mind that most day to day tasks also involve the use of skeletal muscle).

We have rightly criticised the CBT/GET proponents for relying on subjective self reported improvements in physical activity and 'fatigue' without using objective measures such as actimeters which would unambiguously show whether overall activity levels increased or whether structured exercise merely displaced other everyday activities.

Surely the same criticisms apply here?

I mean, really? Are we going to get a paper at some stage entitled something like 'Moderate exercise improves subjective reporting of physical function in patients with chronic fatigue'? Will this do anything to enhance our knowledge and treatment of ME?

It would be nice if proposals for moderate exercise as a treatment for ME/CFS were placed within a coherent theoretical disease framework. At least then we might have a hypothetical justification for recommending it which could be tested.

At the moment the only rationale appears to be the usual 'exercise is good and avoids deconditioning'?

Due to the fact that we don't know for sure what is making us ill we also don't know whether exercise will help us, make us worse or even if tolerated is a useful use of our time and energy.

Don't get me wrong. I'm not saying that there is no value in exploring the conditions under which we may be able to tolerate exercise and the extent to which it might help (or not) with physical function.

There is potential here to learn more about the underlying pathology but not if we just focus on physical activity and not if we just focus on exercise as an end in itself or to justify a programme of 'pragmatic rehabilitation'.

We have had quite enough of that over the years.

Thank you Marco, I agree with everything you said.

For over a year now, I've been pretty good at baseline, and even Dr Myhill says it's at this point that one can proceed with the right kind of exercise. I've very carefully been attempting to expand my energy envelope with the "right" exercise for over a year, without any success whatsoever. It won't budge. Something is indeed FIXED, and my latest focus has been on getting it UNFIXED. So far even Mito support is not helping either.
 
This is a response to a comment on another thread. I'm posting it here because I don't want to hijack and distract from the main message of the other thread.

Hi CBS,

I'm curious...do you have a link quoting Klimas recommending exercise for severe ME patients?

Thanks in advance,

d.

Hi Danny,

In the first video, neither Dr. Kilimas nor the physiologist (Ms. Sol) differentiate between mild, moderate or severe ME. I think that's a mistake. I understand that their focus is on VO2 max and I do not disagree with that aspect of the recommendations. However, I suspect that just getting to the clinic for testing will put many severe ME patients past their aerobic threshold. I have also found that too much low level activity in a day (never going over 85 BPM) has a cumulative effect and can bring on a crash. That is not addressed in the first video either. Too much cognitive activity can also easily and predictably induce a crash now (with no physical activity).

For the first 13 years of my ME, I remained as active as I could without bringing on a crash. However, I did not appreciate the real and permanent damage that could be caused by exceeding my "energy envelope." I'm now is a situation where just getting the laundry and dishes done is often simply too much no matter how much I space my activities during the day. I'm caught in a position of needing to move into a much lower maintenance living arrangement but not daring to go through the ordeal of moving out of a house I've been in for over a decade. I literally don't dare move and at the same time I can't even manage coordinating yard and house care (and I'm one of the very few lucky ME patients that has a spouse with an income that makes this affordable - BUT it's still not manageable)

I have a lot of respect for Dr. Klimas but I think that rather than guiding an "exercise" program, what many moderate to severe patients will find with VO2 max testing is that they ought to sell their houses, hire yard and housing cleaning services, order "meals on wheels," move to condos, stop trying to work part time, etc.

I also think that the message can easily be misconstrued, leading to patient abuse as few doctors will read beyond the inference that "CFS" patients can and should exercise (I know my PCP would not take the time to watch this and I would never share this information with him for that reason. I would however get a VO2 max test done if I could do it without his knowledge - and my PCP is better than most!).
 
Thank you

Thanks Shane for your explanation in more detail. I certainly agree with all your points. I haven't watched the video(s) yet, but will do so when I have more 'energy', but you bring up many valid issues, and if those concerns and issues aren't addressed, they definitely should be.

I too am in the same boat as you (except, no one around to help, but lucky to rent out a tiny one bedroom at a bargain price -- rent hasn't been raised in 11 years, knock wood). But I know I'll have to move at some point and that is quite honestly terrifying, considering my current state. I too was kind of able to manage (barely) without bringing on a severe crash...until Dec 2009...and then even an even more severe downslide again Oct-Dec 2010...from which I'm still paying the price, so can totally relate. I refuse to believe the 'damage' is permanent, but of course time will tell.

I also respect Klimas very much. She doesn't charge an arm and a leg (and a few other body parts like a colleague of hers who shall remain nameless), and she has a much better track record than he does. IMHO she's an honorable person with the best of intentions for her patients and the patient community.

Having said that, your concerns and recommendations are very valid, and should be incorporated into a revised or updated version of the video.
 
For the first 13 years of my ME, I remained as active as I could without bringing on a crash. However, I did not appreciate the real and permanent damage that could be caused by exceeding my "energy envelope." I'm now is a situation where just getting the laundry and dishes done is often simply too much no matter how much I space my activities during the day. I'm caught in a position of needing to move into a much lower maintenance living arrangement but not daring to go through the ordeal of moving out of a house I've been in for over a decade. I literally don't dare move and at the same time I can't even manage coordinating yard and house care (and I'm one of the very few lucky ME patients that has a spouse with an income that makes this affordable - BUT it's still not manageable)

I have a lot of respect for Dr. Klimas but I think that rather than guiding an "exercise" program, what many moderate to severe patients will find with VO2 max testing is that they ought to sell their houses, hire yard and housing cleaning services, order "meals on wheels," move to condos, stop trying to work part time, etc.

I also think that the message can easily be misconstrued, leading to patient abuse as few doctors will read beyond the inference that "CFS" patients can and should exercise (I know my PCP would not take the time to watch this and I would never share this information with him for that reason. I would however get a VO2 max test done if I could do it without his knowledge - and my PCP is better than most!).

[my bolding]

CBS describes my situation very closely. I, too, exceeded my energy envelope for a long time. That's what I learned from VOmax testing -- walking across the room exceeded my AT, climbing half a flight of stairs exceeded my AT, showering, towelling dry, and dressing each exceeded my AT. This is after I'd been maintaining a normal lifestyle for a number of years because my doctors swore there was nothing wrong with me. I was pretty gullible at the time. :D

I'm capable of being out of bed, but not cooking for the family or doing household chores without exceeding my AT..... Well, okay, I've learned to clean the bathroom sitting on the floor 5 mins at a time followed by laying supine on the bathroom floor for for 5 mins. That's my "exercise"... and it's hard to stay below my AT doing it. The idea that I would deliberately lift weights or do leg lifts when I can't clean my kitchen, do the laundry, or cook dinner without going over my AT seems kinda silly....

It's not like I haven't tried the exercise-(or stay active)-staying-under-your-AT program... I worked at it for a couple of years until I was bedbound. I never made any progress. I still use the general philosophy when I have to do something (like clean the bathroom).

This isn't to say that this exercise won't work for many, or even most, PWME --my own daughter is likely one of them -- but I agree with CBS that this "exercise program" could easily be misconstrued and probably dangerous to some of us if mandated.

This does NOT mean I'm opposed to it; in fact, I think it's a great idea as long as it's used intelligently and with awareness of the individual patient's condition.

I'd love to know what it is that has CBS and I (and no doubt others) in the situation we're in. Maybe it is some kind of serious mitochondrial damage.
 
Thanks, Marco

Marco,

I've really appreciated your posts over the past months and feel I've learned a lot from them. (Unfortunately, my doctors don't seem to give your ideas the same value as I do, but perhaps the new ICC guidelines can help me there.)

In post 22 you said, amongst other things, 'The question is if, and to what extent, a programme of physical exercise may be able to enhance the capacity of your body to produce energy. It may do, if carefully controlled and supervised to avoid crashes, and over time allow for some improvement in function (but not a cure).

On the other hand there may be no effect or negative effects. The available energy is fixed at a reduced level and any structured exercise programme is energy used that could otherwise have been used for everyday tasks that are of more intrinsic value to people's capacities and well being (bearing in mind that most day to day tasks also involve the use of skeletal muscle).'

I agree with the idea that normal energy requirements take priority and I have used this line of thinking to judge whether to go to gym or not on any particular day, or even week. However, I've been ill since 1996 and when I first went to gym at the end of 2009 I felt like a frail shadow of my earlier healthy self. Even climbing the stairs to the gym left me breathless. Now, although I am very careful about energy expenditure there, I have a sense of myself as being more physically capable than I was when I began. I've gone from lifting 1kg in each hand to 4kg. (However, my aerobic ability has lifted only a little and the stairs still take my breath away.) After reading about the Klimas study I'm being even more careful than I was previously. But the point of my post is that I think it is worth trying the least taxing regime you can sustain over time. Even just being amongst others for a while helps me feel I'm still part of the community and makes me happier.

cheers, Lynne
 
I have also found that too much low level activity in a day (never going over 85 BPM) has a cumulative effect and can bring on a crash. That is not addressed in the first video either. Too much cognitive activity can also easily and predictably induce a crash now (with no physical activity).

I think this will be addressed. As I noted in a earlier post - the key factor determining whether one should exercise during the day - is heart rate after awakening. If baseline heart rate has gone up - then it's not appropriate to exercise that day. Dan only does his exercise routine a couple of times a week because his heart rate after awakening tells him that if he does that he will crash.

That means you have to find your proper activity levels in order to do this program at all. If you're constantly pushing yourself past what's healthful for you - you can't do the exercise routine at all!

'Exercise' for the severely will, I have been told, be addressed in the 3rd video - there's still alot to come.
 
I also think that the message can easily be misconstrued, leading to patient abuse as few doctors will read beyond the inference that "CFS" patients can and should exercise (I know my PCP would not take the time to watch this and I would never share this information with him for that reason. I would however get a VO2 max test done if I could do it without his knowledge - and my PCP is better than most!).

I'm sure some will misconstrue it but I hope some factors will keep it from being readily misconstrued. This is a 'heart-rate based' activity program. Hopefully if that fact - which does illuminate physiological factors in CFS - is kept up front and center and physicians understand that determining AM heart rate is a key aspect of this program - this program will actually help recontextualize CFS for them. I certainly hope so.
 
...This is a 'heart-rate based' activity program.

Then why not call it that? I think that's a far better title. I still have questions about using heart rate in this population as fluid volume can have such dramatic effects on HR. To me, this raises questions about the reliability of HR and using it for something as important avoiding serious complications and lasting functional decrements.

There is a long history of ME advocates, doctors, and patients going to great lengths to ensure that those unfamiliar with the disease misunderstand what it is we are dealing with by using terms in non-traditional ways (exercise, fatigue, CBT, etc.). when we do this we set our selves up for having to explain what we really meant.

When will we stop shooting ourselves in the foot?
 
I'm hopeful this program is based on a lot more than just ones AT (as determined by the VO2 Max), because from my experience, that alone is grossly inadequate for these purposes. Since it's Dr Klimas, I'm giving the benefit of the doubt and waiting to view the video's before making judgement.
 
Thanks for you comments Lynn (if only I could remember what I'd written over the last months:D)

I really should be wary of trying to project my own experiences onto others. I realise that I've been lucky in that while I lost and never regained the capacity for aerobic exercise I have only really lost significant physical function when in full crash at which stage I can't walk at all. To go from being fully mobile (capable of walking for miles at a steady pace) to unable to walk in a matter of minutes does not suggest to me that the problem lies in muscle tone or deconditioning particularly when the trigger can be a 20 minute social phone conversation.

Plus to be frank, I managed 20 years of education and office based work without ever needing to draw on aerobic capacity. For most workers these days aerobic exercise is a leisure pursuit/lifestyle choice which I miss but can certainly live without. It was other factors that put me out of the workforce.

My experience, like yours, is that muscle strength can be regained and relatively quickly, if this is a problem, although again I agree that it doesn't seem to impact on overall aerobic capacity.

Anyway, at my age I'm way past realistically expecting to play squash again so I'm happy to leave exercise and sports to the youngsters.

OK I'm being a little facetious and I appreciate this is in no way what is being proposed but, in short, rehabilitation for me would be to regain a range of basic physiological functions (e.g. digestion; respiration; restorative sleep; cognition; temperature regulation) that I seem to have lost the capacity to regulate or sustain.
 
Thanks for you comments Lynn (if only I could remember what I'd written over the last months:D)

I really should be wary of trying to project my own experiences onto others. I realise that I've been lucky in that while I lost and never regained the capacity for aerobic exercise I have only really lost significant physical function when in full crash at which stage I can't walk at all. To go from being fully mobile (capable of walking for miles at a steady pace) to unable to walk in a matter of minutes does not suggest to me that the problem lies in muscle tone or deconditioning particularly when the trigger can be a 20 minute social phone conversation.

I think even Dr. Klimas's best responder to the program would agree that more than muscle tone or deconditioning is involved but I also think she would say that those two things can and have really impacted her quality of life. (I have an interview with her coming up). She had tried exercise'/activity management programs before and failed miserably. She was at the point where she couldn't handle physical therapy. She was pretty bad off although not nearly as bad as some people. It took awhile but she responded very well to this program- other people surely won't respond as positively....although I have been told that the outcomes are generally positive.

I know that we generally highlight the success stories on treatment issues - skewing the curve so to speak - but as Dan's series unfolds I am going to try and reach Dr. Klimas about this and see what she has to say.
 
I agree with CBS and am pretty much in the same boat as SickOfCFS.

With the caveat that I haven't watched the videos (computer problem) - I really want to see very careful wording in this series. I much prefer the word activity, 'heart-rate based' activity program' is great. I think strongly stressing illness severity in EACH video is appropriate. Having things taken out of context is a constant danger. If someone hear what they want to after video one they might not come back to see the rest. I shudder to think what Trine might do with this. The E word can be as harmful as the F word.

I have some confounding issues which make me dubious about this as it applies to me.

** My capability to do aerobic exercise was destroyed after a virus nailed me 30+ years ago so I don't even know if I have any meaningful "AT".

** This is been a one-way ride for me - i.e. no remissions of any sort in all that time . Since that time and I've gotten worse at an ever accelerating rate. I'm in danger of getting worse permanently every time I over do it and life forces me into that situation regularly. There is no way I can get on a bike today - it could send me to bed indefinitely.

** I've got POTS which really throws the HR thing off. Currently the treatment is holding my HR down to the point that I often can't get above 50 after minor exertion which mean I can't catch my breath at times. I've got to try and fix that but the benefit to my other autonomic problems is great enough that I'm afraid to mess with it.

So I don't know how to apply a HR-based approach.

Hopefully I'm not the norm (most would agree ;) ) and this will be helpful to some, and maybe I'll glean something helpful here as well.
 
I, personally, don't understand why one would spend very much time developping that kind of activity/exercise program. If they could find out what's wrong with us and how to fix that we would be helped much more. When i got ME/CFS i was well trained, but much sicker than now, where i'm probably deconditioned to some degree. So the problems we have don't come from deconditioning, in my view. I don't want to interrupt this discussion, i just don't think this kind of approach could get us very far and it might also have some dangers. But in the end everybody has to find out for themselves what they want to try.
 
Because I'm one who inserted a somewhat negative note to the discussion of this video/program, I want to make clear that I really respect Dr Klimas, and believe that she has a great deal of knowledge about ME patients and their issues, so I'm confident she has given this exercise program a lot of careful thought. I know that heart rate monitoring and staying below my AT has been a big help for me in managing my symptoms.

My concerns are that her ideas could be applied by patients or doctors without her understanding of the underlying issues, and that there may be subtleties having to do with treatment prior to using this method, for example, that wouldn't ordinarily be addressed in a fairly short video. So I'm not arguing against the exercise program, I'm just suggesting that caution be used and that the program not be assumed to be appropriate for all PWME without a lot more research behind it.
 
I, personally, don't understand why one would spend very much time developping that kind of activity/exercise program. If they could find out what's wrong with us and how to fix that we would be helped much more. When i got ME/CFS i was well trained, but much sicker than now, where i'm probably deconditioned to some degree. So the problems we have don't come from deconditioning, in my view. I don't want to interrupt this discussion, i just don't think this kind of approach could get us very far and it might also have some dangers. But in the end everybody has to find out for themselves what they want to try.

Why would Dr. Klimas do this? Because after treating people with ME for 30 years or so and trying all sorts of different things - she's found that it helps. It also based within a theoretical construct - reduced aerobic capacity in ME/CFS - that probably makes sense to her.

I don't know who exactly this program helps but my guess is that it's enough of a segment of the CFS population for her to be happy to get the word out about it. I imagine that she's well aware of the controversies regarding this subject and take some hits for it - but she's willing to do this.

I'm sure that she'd love to spend her time figuring out what's going with ME/CFS - she spends alot of time doing that anyway - she is a very busy ME/CFS researcher. Until that answer is found, though, physicians -as they should - will look for ways to ameliorate their patients symptoms however they can.
 
Why would Dr. Klimas do this? Because after treating people with ME for 30 years or so and trying all sorts of different things - she's found that it helps. It also based within a theoretical construct - reduced aerobic capacity in ME/CFS - that probably makes sense to her.

As a final word on this, the above statement covers two seperate issues :

'pragmatic rehabilitation' (where have I heard that before?) where empirically derived treatments may be found without illuminating the underlying pathology;

and a coherent disease model that might predict how various therapies might help or hinder recovery and which could point to a cure.

In principle, I have no problem with the former approach as long as it does no harm and provided this approach is not at the expense of, or has diverted attention from getting to the root of the disease as unfortunately has happened in the UK.

As for the latter, with the greatest respect 'reduced aerobic capacity in ME/CFS' is not so much a theoretical construct as a simple statement of the obvious. I think most of us a pretty much painfully aware that we have reduced aerobic capacity - as a consequence of our illness although I accept that over time some deconditioning may occur.

The question is why - and what does this tell us about the disease?

Any coherent theory has to be able to explain, for example, what causes many of us to transtition from a normal pre-morbid state to reduced aerobic capacity literally overnight. It also has to explain how reduced aerobic capacity explains PEM that results from relatively trivial activities (e.g. cognitive) that make no aerobic demands.

Call me a purist, but 25 years plus of research really should be delivering more than just supportive therapies that may only impact one aspect of the disease.

I'm not asking for 'the answer'. Just a coherent explanation of how PEM and reduced aerobic capacity fits within the underlying pathology of the disease and are not just symptoms to be managed.
 
As for the latter, with the greatest respect 'reduced aerobic capacity in ME/CFS' is not so much a theoretical construct as a simple statement of the obvious. I think most of us a pretty much painfully aware that we have reduced aerobic capacity - as a consequence of our illness although I accept that over time some deconditioning may occur.

I have to disagree or maybe I would just alter the emphasis. The fact that 'reduced aerobic capacity' can be proven using validated instruments to the medical community is huge. The fact that researchers can or are proving that it is not the result of deconditioning is immense. That places ME on a whole new playing field. It may be obvious to us that we have reduced aerobic capacity but not to the research community (ie CFS is not called 'reduced aerobic capacity disorder' :).) If that could REALLY be be established imagine the difference in emphasis. Showing that symptoms occur more readily when patients push themselves outside of their (relative) energetic cardiovascular safe zone - should shift the conversation.

I'm not asking for 'the answer'. Just a coherent explanation of how PEM and reduced aerobic capacity fits within the underlying pathology of the disease and are not just symptoms to be managed.

Agreed! I think that is being worked out with the Lights, Snell and Stevens at the Pacific Fatigue Lab, Newton, the Spanish group and others. The Lights have found increased cytokine levels after exercise and now they are collaborating with Dr. Klimas. She will look at immune functioning in the subsets they turned up and they will look at the gene expression levels in her low NK cell functioning patients. I have been told that she believes some significant answers will show up in the next couple of years.