Repeat Test Reveals Dramatic Drop in ME/CFS Exercise Capacity

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Hooked up for a CPET

Simon McGrath reports on Dr Snell's new study demonstrating that ME/CFS patients have a reduced capacity to exercise when they repeat a maximum exercise test one day on - unlike healthy controls.

One of the biggest problems of getting ME/CFS taken seriously is that often we 'look' normal, even though we feel lousy, and most lab tests produce 'normal' findings. How do we prove to the world that we are sick?

A defining feature of ME/CFS is Post-Exertional Malaise (PEM) and a couple of studies have clearly demonstrated PEM in patients [see box]. However, PEM is a subjective experience and one that can only be measured by patient self-report, which won't satisfy everyone.

Dr Chris Snell, Staci Stevens, Dr Todd Davenport, and Dr Mark VanNess's new study aimed to objectively demonstrate the problem of post-exertional malaise, by using a repeat Cardiopulmonary Exercise Test (CPET). As they formally hypothesized in their paper: "an exacerbation of symptoms following the first test would be reflected in physiological responses to the second".


The study

The 51 CFS patients were all women, met Fukuda criteria and also reported PEM. Controls, also female, were similar in age and BMI, and were fairly sedentary. In fact, the results of the first CPET revealed that the controls were in the bottom 10% of published population norms and would count as deconditioned. CFS patients were barely different from controls so were also deconditioned, but, crucially, they were ill while controls were healthy, casting doubt on the idea that deconditioning is responsible for CFS.


CPET: Cardiopulmonary Exercise Testing explained

CPET is the Gold standard for measuring physical capacity, used by athletes wanting to measure the effectiveness of their training programs. It's also used medically e.g. to diagnose cardiovascular, breathing and muscle disorders.



The principle is to get someone to exercise to exhaustion, using a protocol that starts easy and gets increasingly difficult until the subject can do no more. The key measures for this study are the Volume of Oxygen consumed (VO2) and the amount of work done, measured in Watts on the exercise bike.


Anaerobic/Ventilatory Threshold

A critical factor is the anaerobic threshold, the point at which the body has to supplement normal aerobic (oxygen-burning) metabolism with much less efficient anaerobic metabolism, creating lactic acid. This threshold is measured in CPET by finding the point where carbon dioxide (CO2) starts to be produced faster than Oxygen, and is called the Ventilatory Threshold, or VT (strictly, VO2 VT).




VO2 max versus VO2 peak

One challenge of CPET is detecting if the person is using maximal effort, as opposed to trying pretty hard. Data showed that CFS patients and subjects here all went deep into anaerobic exercise and met at least one other measure of high effort. However, as it's almost impossible to be completely sure, the study reported 'peak' measures instead of maximum, e.g. VO2 peak, not VO2 max.

Note there are equivalent thresholds for work output, in watts: W max, W peak and W VT

More: Lannie's blog on PR about her CPET at Pacific Fatigue Labs.


Day 2 results separated patients from controls



A Day 2 CFS patient...

The big differences between the groups emerged on the second maximal CPET test, 24 hours after the first. On average, controls did slightly better on Day 2 (something that has been observed in other studies too) while patients did substantially worse. Interestingly, VO2 peak did not differ significantly between patients and controls, but peak Watts output was significantly lower, as was VTO2 . The biggest difference of all was for Watts output at VT, down for the patient group by over half.

The study found the repeat test could separate CFS patients from controls in this sample with 95% accuracy (3 errors in total). They also used a statistical technique called 'cross-validation', which indicated the test would achieve a 90% accuracy in an independent sample (though see issue with convenience sample below).

This ability of a 2-day repeat test to discriminate healthy but sedentary controls from CFS patients is critical. In theory, doctors can manage this easily enough without a CPET test. However, where there is doubt about the reality of symptoms, as can happen with disability insurance claims, an objective test can demonstrate that a patient really is sick. As Workwell Foundation notes, it's useful in legal or medical disputes; the reduced performance on VT is "impossible to fake", adds Dr Snell.
The study conclusion said:
the post-exertional state in CFS is characterized by objectively measurable deficits in submaximal metabolism and workload that would be nearly impossible for patients to fabricate
In some ways the findings are unexpected, as it was the same group's earlier finding of a substantial drop in VO2 max on the second test that caused such a buzz amongst patients. And the big drop in output at VT wasn't seen in a study (albeit a small one) by a separate research group, though a smaller drop was seen for VT, and VO2 max in a study presented at an IACFS conference. I asked Chris Snell if he was surprised by the finding. "No", came the reply: the initial study was small making the findings less robust, and he said that a much bigger effect on VT than VO2 max has been seen in the clinic too.


Evidence of Post-Exertional Malaise from subjective studies
As well as the objective evidence from this new paper, PEM has been shown by self-report measures too. A 2010 study from Pacific Fatigue Labs found that only 1 of 25 female CFS patients recovered from a maximal exercise test 48 hours later while all 23 sedentary controls did. Another study using a moderate exercise test found that fatigue and pain increased in the 48 hours after exercise in CFS patients - while it returned to normal in that time for both healthy controls and Multiple Sclerosis patients.

Committed to Maximal CPET

Given that it's hard enough for people with ME/CFS to do one maximal test, let alone two, these results create the temptation to just run the second test as far as the Ventilatory Threshold and forget about VO2 max. But Chris Snell stressed that the Workwell Foundation remains committed to the repeat-maximal approach. First, VT can't be measured on the fly so they wouldn't know when to stop the test. And perhaps more importantly, the post-exertional effect appears to differ by patient, with some showing a greater effect on peak measures and others at VT. Dr Snell suggested that varying post-exertional responses may well reflect different underlying pathologies.


Unique to ME/CFS?

Is this the killer test that uniquely identifies CFS patients? Dr Snell has reported that their clinic has tested patients with numerous illnesses including Multiple Sclerosis and Congestive heart failure, but have only seen the problem in ME/CFS patients. Published studies show normal repeat CPET performance for sarcoidosis, angina, Chronic Airflow Obstruction, Pulmonary Hypertension and heart disease. I’ve seen no studies showing failure to reproduce CPET results in other illnesses, but it’s probably too soon to say if this is unique to ME/CFS, or just very unusual.


What might cause the exercise problems?

The authors suggest that a synergy of small effects across multiple systems could be responsible for the poor exercise performance of the individuals with CFS. Lower oxygen carrying capacity could result from low blood volume, while low oxygen consumption could also result from autonomic dysfunction and reduced ventilation. But research into the causes is needed.


No study is perfect...
  • There were only 10 controls, though as the repeatability of CPET results is firmly established (with 94% reliability between tests), in some ways controls mainly serve to demonstrate that the protocol and equipment is working properly.
  • The CFS patients were a convenience sample, rather than, for example, consecutive referrals to a secondary clinic. This, and the fact that patients had agreed to a repeat maximal exercise test, means the results might not generalize to the patient population as a whole.
  • The earlier study by this group, and the other studes from independent groups, didn't find the dramatic changes with workload at the ventilatory threshold, so further replication would help to confirm the nature of the changes.
These findings, which make visible the hallmark ME/CFS problem of post-exertional malaise, have potentially huge importance. Replication of this study, perhaps with a more representative sample of CFS patients and some sick controls, should in my view be a priority for the research community. Stage two of the huge CDC multi-clinic study could provide the perfect opportunity for this.

Simon McGrath tweets on ME/CFS research





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Comments

Personally, I'd rather risk a pretty massive crash before I'd have a lumbar puncture.
(Actually, I'm not sure I'd not prefer to die than have a lumbar puncture, but that's just me.)
 
Not exactly. :) Doctors do surgical biopsies and spinal taps when necessary for diagnosis. Both these procedures cause some degree of "harm". Some amount of trade-off is accepted.

The relevant difference between the CPET test and GET is that the CPET is a one-time diagnostic(theoretically) from which one can recover, although it takes time. GET is presented as a continuing therapy, constantly stressing the system and not giving it time to recover.

That said, I agree that 2-day CPET testing is not ready to be used as a universal diagnostic. First, it needs to be confirmed. Second, there's still a lot we don't know about it and its usefulness. My hope is that using 2-day CPET testing in research will provide enough information that someone will be able to develop a less "destructive" test for diagnosis.

I have never done the 2-day test. I did the one-day maximal test while I was mild-moderate and had a moderate crash that was a week or two long. Not fun, but not catastrophic. I've had as bad, and worse, crashes from other activities and infections. It wasn't so bad that I wasn't willing to do it again about 5 years later. The second test was not maximal, though, only to VT and was easy -- no crash afterwards.

We've all had crashes. We get up, we move on. I'm willing to crash (as a one-time event), if necessary, to improve the knowledge base in this illness, especially if it's a planned crash so I can arrange my schedule, and maybe stick a few meals in the freezer. ;)

Maybe we need to hear, all in one place, from some of the people who did the 2-day CPET -- what their condition was before the test, if they crashed and for how long/badly, what their condition was after the crash. Anybody willing to chime in with their experience?
I agree with much of what you say, but not all. Some people do not recover from crashes, but become permanently even more impaired. If people are managing part-time work or self-employment, a crash can have a serious impact on income for a person who may already be on the breadline. This happened to me in 2010 when over-exertion caused a crash that landed me in hospital. I ended up building up a large credit card debt which I have only just paid off thanks to maturation of small occupational pensions accrued before I became ill.

No one has a right to make someone suffer such adversity just to prove that they are genuinely ill (and I do receive two disability-related 'benefits' - the disability element of Working Tax Credit, and a reduction in my council tax, and these have entitled me to a few further benefits such as free medications).
 
Good point. I was a bit too flip there with the "we get up, we move on". Every crash I had in my viral-ish days left me little bit worse. Because my illness wasn't as well-managed in those days, I never lasted long enough between crashes to recover that little bit back. Every crash made me a tiny bit worse, and the accumulation was a slow but steady downhill slide.

I guess I was thinking of participating in research -- I would plan ahead for a crash and do everything I could to ensure I had the opportunity to go into mega-rest mode for up to a couple of weeks afterward. This is what I've done for other important things -- my mother's funeral, for example. Not exactly "we get up, we move on" :whistle:. More like, we sometimes do what we have to do.

No ME/CFS patient should be required to do a two day CPET. The potential consequences are too high to require that from anyone. I hope some people at all stages of ME/CFS will choose to do the test for the sake of forwarding our knowledge. I also hope those patients will be under the care of a good ME/CFS doc who will help deal with the symptoms involved in the crash -- autonomic dysfunction, infections, cardiac problems, whatever they are. To plan research on severe patients without that kind of post-test support borders on unethical.
I replied to your earlier message before seeing this one, SOC. Let me know if you want me to edit it, as I agree with you now! :)
 
I had the test for disability documentation. I can't speak to how they did it for clinical trials, but the disability test includes a symptom questionnaire that asks you about symptoms for a week after the test. I did have PEM symptoms for more than a week, but I think a week's cut-off is practical for the purpose of documenting disability...meaning that being sick for a week after exertion is enough to interfere with your ability to work full-time consistently week to week, and after that going on to be sick for more days isn't relevant for that purpose. Also, self-report of symptoms, as we all know, isn't measurable and objective, so it has only a little usefulness in the context of the whole test. It's more in the nature of supporting evidence.

I had no permanent or long-term setback from the test. I think I was fully back to baseline within 5 or 6 weeks and the really bad symptoms only lasted about 4 days. I am fortunate in having no particular responsibilities beyond basic self-care, so with preparation (lots of food laid in and everything otherwise arranged so I didn't have to go out or do anything but rest) the recovery period was long, but not agonizing or stressful. I was hitting my pain pills far more than usual due to muscle pain - that is, flu-like muscle pain, not muscle strain from unaccustomed exercise, although of course I had that too. Easy to tell which muscles got overworked from a bike test. But the muscle strain went away real fast compared to the PEM muscle pain.

The worst crash symptoms actually did not fully set in until four days after the test. I actually felt OK on the second day in terms of general malaise symptoms - better than I expected. In fact, I got home OK (short flight Sacramento --> Los Angeles, accompanied by my dad) and was all settled in for my recovery period before I started feeling really sick.

But - and this is important - I still had a *huge* plummet in my performance (workload at ventilatory threshold went down 60%) from Day 1 to Day 2 even though I certainly didn't *feel* 60% worse at that point. From this, I think it's possible that PEM symptoms do not track exactly with the decrease in your energy production capability - the decrease in ability to seems to happen quickly, but all the inflammatory-type symptoms may take longer to fully build up.

I don't know how this fits with the Lights' findings that pro-inflammatory cytokines go up within hours of an exercise challenge. It may be that the cytokines don't have their full effect for a while after they start being produced. Or, it could be that the cytokines continue to rise after the Lights' relatively short follow-up time...meaning that what the Lights are measuring actually isn't yet enough to provoke major symptoms, but it indicates the disease process is kicking off. Or that the body can clear the cytokines for a while at first but is eventually overwhelmed by them. I don't think this is a fault in their research. They are not looking at the entire life cycle of a PEM episode, but for a biomarker that distinguishes people with the disease from people without it.
I have been trying to work out the sequence of events from my own exertion, but don't have time to go through all my notes and do a proper analysis, as I am still having to work self-employed to keep the wolf from the door. It's very frustrating.

But so far I have observed:

1. Initial muscle pain that lasts up to about 48 hours, often much less
2. No obvious worsening on 2nd day
3. Mild head and neckache, arm muscle tightness, calf muscle twitching, apparent solute diuresis (evidenced by polyuria that does not respond to desmopressin) Mild upper abdominal pain? Looser bowel movements? Swollen cervical lymph nodes and submandibular glands with very pale skin over them? Twingeing maxillary lymph nodes? Itchy and blocked ears?
4. Poorer sleep, mild-moderate toothache.

There are other symptoms that I haven't included and I am not 100% sure of the chronological order.

Possible explanations for some observations:

  • Excess lactic acid production overloads the liver, hence upper-abdominal pain
  • Hyperlactaemia acidifies gut, hence loose bowel movements, possibly including loss of some nutrients that way
  • Solute diuresis involving excretion of excess lactic acid as sodium lactate and other salts
  • Consequent mineral deficiency leading to toothache and poor sleep

After my first severe episode of hyponatraemia I started suffering dental damage and also had my only-ever fracture, from a minor fall, supporting my theory of mineral loss, hence the fact that I now take a bone mineral supplement. I don't get these severe effects any more.
 
Personally, I'd rather risk a pretty massive crash before I'd have a lumbar puncture.
(Actually, I'm not sure I'd not prefer to die than have a lumbar puncture, but that's just me.)
I wouldn't go that far, but I would only agree to a lumbar puncture to diagnose a possible life-threatening illness that needed urgent treatment. It's a dangerous procedure, the after-effects can be very nasty, and if they go wrong (which some do) it can be catastrophic.
 
I always tell healthies that I'm actually capable of rapid movement in an emergency, though I couldn't sustain it for long and would pay consequences later. I kept saying "I could run from a bear if I had to" so often that my friend asked me if bear attacks were a big problem in my neighborhood. :eek:
I can sometimes react quickly, and sometimes not. If I could always react quickly I would not have broken my wrist in 2008. I could have stopped myself from falling. I would not have sprained my ankle badly on a step more recently. Again, I could have stopped myself from falling. When I am dizzy, or disorientated, or weak, or ataxic, I cannot react on the way I need to, and the same would be likely to apply in a life-threatening situation. Yes - when not already suffering adverse effects from over-exertion, I can - to a degree. But the distance I would be able to run, or, for example, my ability to climb over a fence or up a tree, would be limited by my ability to keep producing ATP fast enough, which would vary according to my state of health but would probably always be less than what it would be without ME.

I also cannot rescue all the wild animals caught by my cats as I used to, which is upsetting. I even accidentally killed a mouse I was trying to rescue, due to weakness, slow reaction times and poor coordination.

I had to turn down my brother's invitation to go on his motorbike to see the solar eclipse a few years ago, as I know there was a danger I would not be able to hold on for long enough, so could end up falling into the road.

This inability to protect myself and others due to my illness is frightening.
 
It's important to define what information you are looking for and why. Since the two-day exercise test is cumbersome, expensive, stressful, and contraindicated for many people, I certainly don't want and don't expect it to become the standard diagnostic test to confirm the presence of ME/CFS...or at least the ONLY test available.

A blood test for cytokines after a mild exercise challenge may become accepted as diagnostic. That would be quicker and cheaper and much more widely applicable. (Actually I've no idea how cheap it is to measure what the Lights are measuring, which is, as I understand it, activation of the genes that produce certain cytokines, not the cytokines themselves.)

Here's one problem though, drawn from my personal experience, that goes beyond the need to diagnose. For a disability claim, they may acknowledge that you have CFS, but refuse to accept that it is as severe as you say it is, or severe enough to prevent you from working. So in that situation, you need some way to objectively demonstrate how much your functional capacity is impaired by the disease, not just the fact that you have it. Being able to measure the severity of disease would also be useful for research. The really tricky bit would be developing a test that shows impairment of functional capacity without requiring the patient to do anything, or a test that "measures" a PEM without provoking a PEM. Unless it turns out that the most severe patients are in a more or less permanent state of PEM, which might be measurable.
I wonder whether blood could be used for a test similar or roughly analogous to that which was conducted on muscle biopsies - subjecting them to the equivalent of exertion in vitro.
 
I wonder whether blood could be used for a test similar or roughly analogous to that which was conducted on muscle biopsies - subjecting them to the equivalent of exertion in vitro.
I have been making similar comments. We need more research in this area. This appears to be the case with fibromyalgia, its probably the case for ME as well. We need this investigated.
 
I replied to your earlier message before seeing this one, SOC. Let me know if you want me to edit it, as I agree with you now! :)
No problem. :) I wasn't clear the first time around, so it's reasonable people would call me on it to clarify.
 
But so far I have observed:

1. Initial muscle pain that lasts up to about 48 hours, often much less
2. No obvious worsening on 2nd day
3. Mild head and neckache, arm muscle tightness, calf muscle twitching, apparent solute diuresis (evidenced by polyuria that does not respond to desmopressin) Mild upper abdominal pain? Looser bowel movements? Swollen cervical lymph nodes and submandibular glands with very pale skin over them? Twingeing maxillary lymph nodes? Itchy and blocked ears?
4. Poorer sleep, mild-moderate toothache.
During crashes I don't have the initial muscle pain, but I do get joint and muscle aches different from overuse muscle pain. They don't usually hit the first day, either.

Before I cleared my chronic infections, crashes used to give me swollen cervical lymph nodes and salivary glands. In the worst crashes, I'd look like a chipmunk, the side of my face were so swollen. The good news is that now I don't get swollen node and glands with crashes, so I'm assuming that they were related to the infections. The toothache thing also disappeared. Doc and dentist think, and I agree, that the toothache was from swelling in the jaw area, not directly dental.

I still get the itchy and blocked ears. I'm wondering if it's a histamine thing...

I can sometimes react quickly, and sometimes not.
For me, there's definitely an element of muscle stiffness (probably from lack of exercise) and clumsiness (which could be related to muscle stiffness or neurological problems) that prevent me from being agile and athletic. I've fallen down stairs 4 or 5 times in as many years. :eek:

Still, if I had only 15 minutes to get out of a burning airplane, for example, I could do it as well as 50% of the other passengers. There'd just be hell to pay later.
 
Me three :) Think we have a couple of threads capturing our thoughts on this kind of testing.
Can you point me to any? Not sure if I have seen them or not. Don't worry if you can't find them easily.
 
I still get the itchy and blocked ears. I'm wondering if it's a histamine thing...
I think there's some evidence that it's lymph-related. I may have saved the info somewhere, and I think it's been discussed on here as well.

For me, there's definitely an element of muscle stiffness (probably from lack of exercise) and clumsiness (which could be related to muscle stiffness or neurological problems) that prevent me from being agile and athletic. I've fallen down stairs 4 or 5 times in as many years. :eek:

Still, if I had only 15 minutes to get out of a burning airplane, for example, I could do it as well as 50% of the other passengers. There'd just be hell to pay later.
I wish I could be as confident. I thought I could react quickly in emergencies but experience has suggested to me that it won't always be the case.

I have very nearly fallen down the stairs a couple of times due to no longer knowing instinctively where my feet and legs are in relation to the ground. One occasion was pretty scary - I grabbed the handrail and involuntarily swung round about 90 degrees, holding on for dear life. That would have potentially been a bad fall, and it shook me up, with visions of breaking my neck as I might well have gone down headfirst and hit the wall at the bottom. It was a close thing. I have been very careful since then.
 
I wonder whether blood could be used for a test similar or roughly analogous to that which was conducted on muscle biopsies - subjecting them to the equivalent of exertion in vitro.
That would be great.

Perhaps more likely is something like the Lights work on gene expression after moderate exercise, which also has the advantage, compared with maximal tests, that it represents real-life situations where patients actually experience PEM. They now have a substantial NIH grant to try to replicate the findings of very different results in ME/CFS patients so perhaps when that study reports there will be an altogether more moderate test with objective findings of abnormal response to exercise.
 
...
That said, I agree that 2-day CPET testing is not ready to be used as a universal diagnostic. First, it needs to be confirmed. Second, there's still a lot we don't know about it and its usefulness. My hope is that using 2-day CPET testing in research will provide enough information that someone will be able to develop a less "destructive" test for diagnosis.

I have never done the 2-day test. I did the one-day maximal test while I was mild-moderate and had a moderate crash that was a week or two long. Not fun, but not catastrophic. I've had as bad, and worse, crashes from other activities and infections. It wasn't so bad that I wasn't willing to do it again about 5 years later. The second test was not maximal, though, only to VT and was easy -- no crash afterwards.

We've all had crashes. We get up, we move on. I'm willing to crash (as a one-time event), if necessary, to improve the knowledge base in this illness, especially if it's a planned crash so I can arrange my schedule, and maybe stick a few meals in the freezer. ;)

Maybe we need to hear, all in one place, from some of the people who did the 2-day CPET -- what their condition was before the test, if they crashed and for how long/badly, what their condition was after the crash. Anybody willing to chime in with their experience?
I agree that this is very important research, and that CPET testing should be carried out with willing volunteers, who know that they will not suffer from long-term consequences from an exercise test.

But I don't agree that "we get up, we move on" after crashes. Obviously, it's different for everyone, but my ME is very reactive and my crashes tend to be severe, deeply distressing and long-lasting, and I spend my whole life trying to avoid them. I would never agree to any exercise testing unless I was in a very stable period of remission and I was absolutely confident that the exercise was within my safe limits. (Safe enough to avoid a crash.)
It is very interesting how we are all different. From my experience having ME for 22yrs would make me a good candidate for this test. I always stay within my boundaries because PENE is something I try to avoid at all costs, it's just too distressing.
I have gone through periods when I felt up to 80% improved fir a couple of years but if I do the SAME amount of exercise as when I'm feeling 40% the PENE is always the same. How I'm "feeling" makes no difference in exercise capacity, so the test result will show abnormalities no matter how well I am feeling at the time of exercise, there will be a unique physiological change upon doing just a small amount. If I'm going through a viral episode the PENE will come on within 2-3hrs, so like someone else wrote earlier is that we need immune testing added to the mix.
 
I think there's a distinction between the ability to produce a short burst of *energy* versus coordination and reflexes. I'm definitely klutzy since I've been sick - I've broken a lot of dishes and water glasses, walked into tables and chairs, etc. etc. But on a bike for the exercise test I managed to put in maximal effort without falling off or anything. No need for coordination or reflexes there - just hang onto the bike handles for dear life and pedal straight ahead.

Of course any given emergency or survival situation is probably going to require a combination of energy, strength, and coordination, so I'm not sure I could make good on my bear-eluding promises, unless it was on a straight even track. And it was a really short sprint. Hmm, this analogy may not be so good after all. Maybe I should go with "escaping from a burning building." Or "getting out in case of an earthquake." Not like those would require balance and coordination or anything..well, I now have no analogies, except "I could do an exercise test on a stationary bike if I had to."

Mind you nobody *requires* you to take the two-day exercise test to prove disability. It's just pretty much the only tool you can use that gives an objective measurement of functional capacity, impossible to fake or exaggerate. And I'd also add that no disability insurer is *required* to take any note of this test or consider it proof of anything, since it is not an "officially" accepted test of disability from CFS. The Social Security Administration, in its guidance on CFS claims, says an "exercise test" may be submitted as supporting evidence but is careful to point out that no test is considered *proof* of CFS or its severity. They could, at their complete discretion, ignore a Stevens test completely, or decide it is invalid or irrelevant. Hypothetically.

Without going any further into matters of which I should not speak...although I have seen a number of reports from people who prevailed in disability claims by taking the test, I feel obliged to point out that it is not a dead lock or a guarantee.
 
I think in ME we are in PEM all the time aren't we. (sorry I am struggling cognitively today). As our threshold for exercise is so low. We are feeling unwell everyday, always something wrong.

As for what day extra PEM sets in after exercise, for me it can happen anytime. There is no predictability. I can head out to an appointment and find myself doing a quick run to catch a bus and that short burst of a run can set me back in an hours time, my inflammation starts intensifying, I feel extremely sick. And there is also the accumulation upon accumulation PEM as well. That can result in a major relapse.

Cheers to the ME sufferers who put themselves up for the exercise testing. x
 
rosie26 I think I tend to equate 'exercise' with physical exercise. And therefore it's more likely to be worrisome and in need of more careful consideration. I'd probably plan some time out to better account for any PEM even if my exercise now equates to a brisk walk.

But a period of 'mental exercise' also can lead to consequences. So unless I have to - see below - I try and break it all up with distractions. Takes me longer but I am the tortoise now to the hare and usually get there in the end.

It is hard to judge what activity or intensity is going to be more likely to lead to a 'flare' and subsequent need for rest. I think through experience we tend to learn our own limitations at any given time and can make judgements accordingly.

Establishing routines if we can that fit to our own abilities is key but retaining some flexibility is also necessary. And that kind of makes it harder to commit to regular things - though I am ever full of praise for those who can.

I was just saying to Simon that I anticipated after my night's stay in hospital, the travel and disruption; and then a 3 hour intense meeting on Wednesday; that I would be in need of at least a few days of cleared decks. It still though comes as a surprise and I find it very annoying when the 'flare' hits.

Not always predictable the degree to which it can affect us - is it? And it's never just about the physical exertion; it's also the mental and emotional that we need to consider.
 
I think in ME we are in PEM all the time aren't we. (sorry I am struggling cognitively today). As our threshold for exercise is so low. We are feeling unwell everyday, always something wrong.
I think that people who are relatively badly-affected may always feel unwell, but I don't, and suspect that many others don't, as long as we adopt measures to prevent it, e.g. suitable diet and supplements and careful pacing. When I feel 'well' I have negligible bodily discomfort and my brain and body are able to do what I ask of them, which has to be not too much so as to avoid PEM later. So I am not recovered, but feel what I regard as 'fine', a lot of the time. I wonder how often sufferers and health workers mix up the two conditions - well and recovered. Is 'well' the right word for feeling OK?
 
I think that people who are relatively badly-affected may always feel unwell, but I don't, and suspect that many others don't, as long as we adopt measures to prevent it, e.g. suitable diet and supplements and careful pacing. When I feel 'well' I have negligible bodily discomfort and my brain and body are able to do what I ask of them, which has to be not too much so as to avoid PEM later. So I am not recovered, but feel what I regard as 'fine', a lot of the time. I wonder how often sufferers and health workers mix up the two conditions - well and recovered. Is 'well' the right word for feeling OK?
I'm in the same place since I cleared my known chronic infections and, equally importantly, learned to use my HR to pace my activities. Without HR-based pacing, I was always overdoing (while doing very, very little) and constantly had symptoms.