Exhaustion in ME/CFS, what is it and what causes it - discussion thread

I wan't actually asking about effort. I was interested in what you meant by exertion to try and understand what you see as a problem

 

I don't believe I said I had any problem with exertion.

 

I have had a good read through the comments. Yes, I totally take your points, @Jonathan Edwards about increasing the intravascular volume. Yes, we do need trials, trials are being done in Australia via OMF for an IV bolus. I see you do not discount that it may have a short term effect which may help people with very severe ME take nutrition. And yes, we need evidence based guidelines and proper evidence.

However, perhaps where I am different, is we, (pwME), should be able to have choices available even if not "scientifically proven" that we can choose to try even if we do not know the future risks. Ultimately it is our life to do with. My GP is aware and there is a clear understanding that I choose a certain "treatment" knowing that I do not know future risk. But yes, that should not be in a national guideline! Our NZ guideline for ME/CFS has not officially been updated by our Ministry of Health, annoyingly so. But most Area Health Boards have clinical pathways that are in line with NICE 2021 (often from pwME asking them to upgrade them). They also have information on how a person with ME may present with cognitive problems, communication problems, pain, cognitive overload and normal temporary stress responses etc.

I appreciate your comment on NSAIDS killing thousands of people with GI bleeds etc but I choose to take ibuprofen regularly for my pain (and it works) and improves the quality of my life. If I develop gastric symptoms, I will inform my GP and no doubt she will say it is time to stop it. Or I could have a massive bleed and die. I am prepared to accept this, but yes, proper informed consent is required for experimental treatments.

I do understand what you are describing regarding signalling. Your comment about "unconscious" does not trigger concern that you are in the BPS school or support the "effort preference" stuff.

I think, and correct me if I am wrong, you are talking about reflexive type responses, things not within our conscious control. All of our body's physiology runs on complex feedback loops involving signalling molecules, eg hormones, on things like blood vessels and central and peripheral neurons. Where this has gone wrong in ME has yet to be discovered.

One thing I observe with my ME, that when I am relapse, crash (my GP calls it a flare), is the slowing of thought, problems with working memory and word finding but sometimes long term memory. But also difficulty getting my limbs to work, they do but slowly and with less precision, like a big block between conscious thought, (I want to move my arm and the speed I can do that) and action. I know there is nothing wrong with the blood supply or neurology or muscle unit. Well, not enough to be "pathological" in the medical sense.

Having intended to be a psychogeriatrician and very interested in cognition before my ME progressively worsened and I had to medically retire, I often observe various behaviours from the eye of a my psychiatric training and I find my relapses with ME does fit into a subcortical dementia like pattern (I won't discuss all the ins and outs of this, nor am I a neuroscientist.) but when crashes have resolved and I am not in PEM, they no longer occur. So something is causing this. Neurological connections is about as far as I can confidently say but I suspect this is part of the autonomic issues ME often have. We know there is work being done on imaging into the structure and function of the ME brain and some useful stuff has come out of this.

My colleagues think they can alter brain chemistry, neuronal pathways etc. with various medications and cure or relieve ME, (so they have moved from BPS, but probably have false beliefs about the power of psych meds!) But I don't think so, I think it is more complex and related to something to do with exertion. All I know from my fellow pwME are that many psych meds are either too stimulating and we crash (especially amphetamine like substances) or too sedating and makes us want to sleep more and thus function less and affects our cognition. Or we use something for sleep and it stops working.

I do think psych meds have a role in helping improve the tolerability of getting tests, transport, having procedures. But I have found with some psych meds, that I have used and are using for sleep, we can get physiological dependence (like all people) and have problems with withdrawal off medication, as we then go through another trial of something else. They should be used carefully and judiciously with a clear rationale of use and plan to be on them for the procedure or treatment, so short term only, not long term (as for all people), because once physiological dependence occurs, (due to up and down regulation in neurotransmitter pathways) you then develop tolerance and then you have to give more and more and after a while your GP will rightly think the dose is unsafe and will only prescribe following psychiatric review. People with very severe ME, there may be quite understandable, compassionate grounds for use and GP's are often prepared to do so.

edit, typos

 

I'm not quite sure what the intricacies of this thread is about. I will try to read through more carefully eventually.

In my severest years it felt like I had just completed a marathon and no amount of rest was helping, so just holding a book or moving a chair gave me very severe PEM and it felt like I was constantly on a rolling PEM because the smallest of effort triggered PEM so easily.

I spent about 10 years on this severer cycle.

Then after all those years of absurd amounts of resting each day it finally felt like I had moved to a more improved level of ME, I was still getting some severe PEMs but not as much.

Now I feel I have improved again where PEM is less severe. Please note that I am still doing the resting routine that I did in my severe years. So for me this amount of rest is how I have to continue to hold on to this better level. I know if I don't keep up this routine I will return to those awful severer years again. Even thought I am better than I was, the ME is still there and able to worsen again.

Regarding symptoms in my severer years, it really did feel like I had run a marathon and my body was so exhausted, my immune system felt down, unable to fight. I was on antibiotic's straight for 6 months because my sinuses were not functioning causing a painful skull and toxic mucus from sinuses.

There is something cutting out recovery in ME. Twenty years of a resting routine/pacing have slowly helped me but this is not recovery, just an improvement that could be temporary if I am not careful.

It took six years from the start of my ME to get to very severe ME where I was completely bedridden. I had still been trying to work full time but getting sicker and sicker. I can look back now and recognize the PEM.

Once you get ME and not cut back on exertion, the exertion will start to lower your threshold for more exertion increasing severer PEM and ME level.

 

As far as I can see the choices are available - if you prepared to pay. If treatments have no proven value then a public health service cannot be expected to pay for those choices.

My concern is something different and much more complex in its implications. I talk about it in my Qeios article. It is about physicians recommending treatment pathways, not just to patients but to hospitals looking after those patients, which are (a) not based on reliable evidence of effectiveness and (b) not based on a sound science but rather on half-baked physiological speculation.

The argument is just the same for GET, CBT and for IV saline. Should patients have the choice to go to GET classes, which sound promising, and end up permanently disabled? Should they have the choice to use fludrocortisone, which may make them permanently dependent on a drug with no benefit to their physiology?

 

Yes I agree.

I haven't said that I think fludrocortisone is appropriate. I personally don't think it is. I don't think it is good idea to play around with hormones.

And obviously I do not support GET.

 

This discussion reminds me of this program on BBC Radio "Janet Treasure on eating disorders and the quest for answers" [I posted a thread here*].
Basically I was reassured having listened to the program -

• there is a remarkably high prevalence in identical twins i.e. indicating a strong genetic component & genes have been identified. I'm hoping that DecodeME might provide clues &/or rare variant studies (whole genome sequence studies);
• they are looking at behavioural approaches - but unlike ME/CFS they appear to be evaluated objectively;
• they are looking at behaviour modifying drugs - ketamine.

Basically although these are "behaviours" they are approached in a non-judgmental way and the idea is to find solutions/supports that work. OK the genetic discoveries presumably helped to remove the judgemental approach but we seem to be a long way from focusing on how understand ME/CFS & deal with it in a pragmatic & evidenced based way - those statements don't apply to this group though!

https://www.s4me.info/threads/janet-treasure-on-eating-disorders-and-the-quest-for-answers.39335/
& blog here - https://slam.nhs.uk/blog/the-life-scientific-professor-janet-treasure-3803

 

That's a nice wording of the problem. It's not conscious control, and it's probably not as simple as one chemical in the wrong amount (it's not serotonin). When you have a bunch of interacting feedback loops, it's really hard to identify a problem, since it's all interacting. Happily, that doesn't mean that the solution needs to be complex. I've had temporary full remissions from several unrelated chemicals, so fixing the right part of that complex system can fix the problem. Finding what to fix is the tough challenge.

 

Colour me boggled. It is in the nature of any sensation that it is a neurological signal. Non pathological sensation typically informs one about a sensed reality.

Question is, what reality do the sensations of ME report? My circumspect guess is informed by observations regarding my own experience.

I have in earlier times been able to ignore pain or fatigue sensations relating to ME and despite much sweat and irritability be active past the point which causes PEM but no amount of exercise will induce the kind of muscle growth which used to increase strength and stamina before onset as part of athletic training. i.e. anabolic process is non functional. I tried.

PEM is like an inflammatory phenomenon and occurs after a certain degree of fatigue plus exertion. The more muscle I put into a task the quicker PEM will be induced. I can feel when I am close to the tipping point as I have to tolerate pain to continue activity. Sometimes I get away with it if I rest but sometimes I dont. This seems to be due to an ongoing immune response of cyclical severity which changes my sensitivity to PEM.

In the early years undiagnosed I tried to be normally active and learned to ignore much fatigue and discomfort. I have had to try to be more sensitive to fatigue sensations in order to self monitor and prevent going past the point which induces PEM symptoms so I can prevent repetitions of induced major cognitive dysfunction, heart arrhythmia, bowel evacuation.

My synthesis of these observations is that ME is a state which provides signals of an underlying change in the primary objective of the metabolism which has switched from activity to an immunological battle.

This is why anabolic processes do not occur and is why tissue degradation products from activity trigger inflammation as though an invader was present, is why the nervous system predisposes its owner to "hibernate" i.e. curl up somewhere safe to get better and eschew physical and social activity until the task is achieved which is typically short term but with ME is not which is the key difference between ME and say flu or simple covid. It may also be why the nervous system is both upregulated to create sensory hypersensitivity and prevent dozy hibernating recoverers being snuck up on by sneaky critters yet also shut down to promote rest and divert energy to the immune system, experienced as brain fog. It is also why the immunological aspects of digestion are hypersensitive and cause food intolerance and IBS.

My guess is that in ME this state change is jammed on because of immune dysfunction of some kind which may differ re genetics of host and pathogens per individual.

 

Agreed. I mentioned exhaustion (as but one of the issues to tackle) on another thread because of the terrible point with Maeve where some HCP hadn't 'got' that her sucking water from a sponge once didn't mean she could eat enough to survive. Of course that seems plain thick, but there are things behind that misthinking that played into that happening.

How do you deal with/explain that in useful guidance when you've got people who 'think' like that. And 'see' exhaustion when they have been brainwashed to see it as 'fatigue' which can be cajoled (not the after-effect of us self-cajoling for too many years, but hey they've an answer for how that's our fault too and not the environment demanding more than our bodies can do).

I think it is worth noting the difference between dealing with worse severities. As you get more severe I became very aware of the sense that there is a point on the ME disability scale (around 20%?) where you are at 'break-even' if you did nothing, including self-care and essential things. And were fortunate enough to have no exertion levied at you like noise and other discomforts (and if you aren't that lucky and it's consistent and you have no control over it that simply gives a different break-even point doesn't it?). But can just about have some time out of PEM being stuck lying in bed.

This point is pertinent because I'm also incredibly conscious that it's a condition where cumulatively if exertion exceeds what you have then your body goes downhill, and probably because of the lower threshold and higher impact of things, maybe because you are so ill too, everything seems to accelerate and there isn't the leeway there used to be (that you weren't even aware was leeway at the time).

EDIT: in fact that point (which I think is around where 'very severe' begins?) needs a term, and I'm thinking of the one in space (is it singularity?). Because after this point it must be that just your functions +body being in that 'ill state' are/can be (?) above threshold, so it is pretty precarious to get through as a path. To get near threshold there's little you yourself can do to reduce these two things.

SO I would guess a term that is part of this 'exhaustion' is the concept of 'recovery from exertion' (not in the sense that term has been bas****ised by BPS, but think maybe 'jog-back recovery' in a training session so you can do another sprint vs 'recovered from that training session' including all the muscle aches etc) or how that gets worse and takes longer the more severe you are.

If you start getting anywhere near that even temporarily then you get very conscious of the price of everything and what needs to be 'saved up' in order to achieve something that to well people would be all energy-giving.

There is something and some point where you realise that digestion, not just the arm movement and chewing of eating, in itself has an energy requirement. Or, if that is nonsense, then your body can be too ill to do it at that point in time but you can then sense when you are feeling a bit better as a moment.

Of course I could cringe writing this, although shouldn't have to, because I know how vile the behaviourists are in making hay with reading this sort of thing and twisting it through the nonsense lens they genuinely believe isn't delusion for 'others'. And think how BPS basically encourage anyone around us to take the pee out of the most ill when they are at the most desperate, and having to communicate its existence (and it gets laughed at).

I think all of these nonsense behaviourist theorists are simply about trying to justify and 'make seem sane' that behaviour and attitude ie make being antisocial acceptable by making those who are victims of it 'deserve it' with their stories. Hence why I always make the point of underlining it being disability bigotry and not 'just' 'ablism' when the shoe fits.

 

No one has claimed to know the root cause to ME or the exact biochemical reactions... Lindberg

This is the fundamental problem. I am a firm believer that ME/CFS is a symptom of another undiagnosed illness. No-one can feel that ill with nothing wrong. The tests are negative, so they are doing the wrong tests.

When I was first ill, I felt like everything was muffled, and I was walking around in a haze. No-one knew what to do. The doctors gave up, but through my contacts as a pharmacist, I found a clinic specialising in this. Unfortunately this clinic does not exist any more, but the doctor who ran it also believed it was a case of finding that cause. Before diagnosis, I could function for about half a day before I felt like I hit a wall that I couldn't push through. I had to give in and sleep for a few hours.
I was eventually diagnosed, through blood microscopy, with Lyme-like illness and the bacterial infection was treated with 6 months of tetracycline antibiotics. After the diagnosis, I had various cell biology tests done which showed that I was a fast user and a slow producer of ATP. Various nutrients were recommended but the most useful advice, which I still follow today, is large doses of D-Ribose ... a form of sugar, more easily converted in the mitochondria for the conversion of ADP to ATP. It's often used by weight lifters to reduce their recovery time after a heavy workout. I'm not saying this is the answer in all cases. The cause is essential to find.

I am now in the position where I can work much more and currently do 2-3 days a week, albeit not consecutive, otherwise the PEM hits and takes several days to fully recover from. I still take up to 10g a day of D-Ribose amongst other supplements but that keeps me relatively "normal".

To touch on other topics mentioned in this thread, I know what I am capable of doing before I hit that "wall" that is PEM, so I do make sure to keep to those limits so, yes, there is a behavioural aspect. Fortunately I'm self employed and can determine my hours.[/QUOTE]

 

Anyway. It becomes a very hand-to-mouth situation of the body where you can't dictate or plan anything for your body it's the other way around and you are trying to know the needs and capitalise on windows which might be better for these when they come up.

I can't imagine what a hospital situation does for this because I imagine it obliterates any of these chances to 'save up' or chance to rest enough to start getting rest (which you need to even start to recover from the prior exertion). Given if you imagine you have to 'save up' your energy even at milder levels for things, by the time you get more severe the amount of time that saving is required just for small things I can't see that happening in that environment because something would exert you, or you'd be uncomfortable in general.

But also because you are not in control of your environment or able to have 'good moments' and use those, it would obliterate any rhythm of finding better windows for anything that needs to be done. And those better windows are important for impact being less as well as being able to actually do whatever it is.

And things that might have seemed more minor become bigger issues perhaps because things are going a bit more haywire and the impact on your body is bigger, but also because weeing a lot has a vastly different impact as you go from mild, moderate, severe, very severe and add in all the issues regarding getting good rest becoming worse with these too.

Just like a heat wave when you are more severe is quite a major thing to even plan through. Hayfever is a different issue in people with other severe comorbidities. Just a lost night's sleep is devastating and can set you into upregulation type feeling where you then can't get your body to rest (it needs rest to rest, but you are in an over-exerted situation) vs when you are less severe and might be thrust into catch-up sleep.

Then what if you have something cut-offs want to call 'slight' or below the reference-range where you would treat, but someone is really ill and it might be seen as 'fine-tuning' otherwise but could make all the difference to whether they can do x without deteriorating and an upwards circle might be possible rather than downward deterioration unavoidable.

Every fix for one thing might have upsides or downsides for others. The patient themselves is doing all sorts of calculations working out eg the taking antibiotics vs the side effects and how to deal with that in a way that is less critical than if you were milder at work and it was a real problem but you had more levers to pull(like taking time off). Pain from one thing can become something accelerating that downhill cycle. Until you get a bit better.

 

So there really, no matter how much I think about it, does feel like a 'load' vs 'threshold/envelope' issue going on.

There is a fatiguability issue (I get this in very standard terms with my arms, now I know this term, it is fatiguability and not 'fatigue' which is behind the cognitive 'fatigue' when my ability deteriorates as a conversation goes on). And there is a 'spent' and 'after-effect/ill' state which equates to PEM. As I've become more ill there is also an ongoing disability level, which motivation cannot beat.

There is definitely a 'faulty recovery' aspect - I agree with @boolybooly for example on how, particularly with certain muscles (calves) usage causes wastage, there isn't that same equation of building up muscle through exertion.

Maybe there is a signalling part of some of it. I'm imagining the concepts being thought of are like Myethenia Gravis where it is signalling to the muscles. And the ideas of 'gas pedals' like things such as thyroid vs 'fuel pipe'.

I like the theory of the trial stuff, and think it is important more of those who are severe (not very severe) have sensible things designed around them. But it is going to have to understand we are not homogenous. And maybe a starting point is histories and symptoms and those who do have some investigations and can talk of their comorbidities etc.

When it comes to this level of issue then 1. it is important to help and 2. people will be so ill with lots of other things then I'm thinking of things more close to what might have been done for some treatments during the earlier stages of covid, where they were seeing what worked for some and just taking notes for those who'd been offered x treatment. To see if these things helped and if there were clues for those it helped best for.

You quite simply aren't going to be able to do trials easily for very severe? Which has nothing to do with how important or severe it is?

For the very severe it is however important that their testimony is believed and the histories aren't gerrymandered by relabelling or misinterpreting basic symptoms or presentations in silly behavioural terms (and I'll say it I wonder whether the weaponising of mental health labels have in the past been a convenient way of covering up death and unnecessary worse disability as 'sad, unfortunate, but we couldn't have changed it') but start to be carefully plotted.

But who is going to do it whilst they've clinics only for 'therapies' for milder with no clinicians? Which certainly shouldn't exempt it needing to happen. But it does need to be the right people given what we've seen.

It's quite incredible we don't have this information so that hospitals know how quickly someone at the level of illness they present needing support with feeding will deteriorate to another level and so on. The level 'just before this' will be completely invisible bedbound at home with no visits.

But that's no excuse for what happens not being mapped - I mean even if it was something reporting in remotely like the Spector stuff during covid.

But then is this sort of thing mapped for sepsis etc? Later or more severe stages of other conditions? I know someone on the other thread mentioned advice regarding PEG and MND for example.

 

I also don't think there are many people who have any clue what is going on with people who are severe, nevermind very severe because we simply aren't seen by anyone and even then for most it can't be to any significant extent.

Particularly these days thanks to the old guideline enforcing a regime where they were banned from investigations many other people might have had in the last few decades. Even if someone was offering them. And then those most who are more ill aren't in a position to do investigations unless they are relevant and necessary.

You'd also need to have hung around a number of people that ill for very long periods of time to understand even some of the basics, never mind the accumulation side of things (and 'riding your limits' eg for 3months). I don't think the standard forms/lens of observation stand a chance, which is another issue.

If we think of the specific context currently then having seen over eg that 6month period people who are that ill seems to be a key part of the lesson. Because I think people are caught off-guard by how things accelerate symptom/threshold-wise and so windows were utterly missed due to presumption things wouldn't change as they did making options that had been possible less possible etc. in short periods of time.

How to get that understood I don't know.

I suspect pwme of all levels are all too familiar with you needing actually to 'adjust ahead' of the condition to turn things around, but that even the kindest of people tend towards 'giving less than you need' as instinct so you then get offered what you needed 6months later, when your needs then mean you need more adjustment etc.

But the thing when it gets more severe is it really takes the patient themselves by surprise too. Faster than they can keep up or catch up with 'more rest'.


Some who end up severe or very severe might have had some investigations or findings however. Which might give clues for something to try and if it helps and when someone then sees something that looks very similar in presentation, and trying the intervention is less risky or more accessible/sensible at the time than the investigation (if someone is suspected Addisons they might be started on steroids before doing a test due to safety in the interim).

I agree it would be great if there was a database collecting the knowledge of what worked for who, and longer-term follow-up too.

I didn't read that these things were being recommended for all in the way that GET, CBT and challenge-based approaches were. I thought I read something saying something along the lines of some can have pituitary issues which can mean... And a big difference is suggesting it as a careful watch and see - which those GET etc ones certainly weren't/aren't - and only continue if it helps and as long as it seems to.

Plus of course them not being suggested as cures for the illness, but as things that might help in the situation where someone has become that poorly. A case of trying to turn the ship around from keeping going downhill to getting far enough out of the woods to get some sort of stability.

I thought the saline was something to see whether if the angle of feeding was immovable the ability to tolerate that angle for a short time could be improved in those it helped for.

I can also see the thinking of trying to do whatever might help to create 'a good moment' (with minimal payback) to building block just enough health to achieve the task needed if it is feeding and that in itself involves exertion that can't be managed without it.

 

Other than my legs (which have a fixed weakness ), I can build some muscle. Possibly even normally for someone with my body-type: slow-twitch predominant and very mobile joints. Decent at endurance, hopeless sprinter, never going to look like a boxer.

I've been able to do it since I first became ill in the 70s, but what I can't do is build muscle or fitness to a high level or maintain it for more than a few years. I'll always eventually get into a downturn where I have to cut right back on activity.

I still have visible muscle development on my shoulders and abs, but I haven't swum regularly since February because I know I'm not up to it. I don't know how long it will be before I can do it again; could be months, could be years, could be never.

 

Well that is a trickier question than it sounds, opening as it does an epistemological can of worms but on a walks-like-a-duck experiential basis...

The evidence for throwing into the ring for consideration the idea that the anabolic process does not seem to happen normally after ME onset is, as I said, my subjective observation I did not get any benefit from exercise and recovery after onset in the way that I did before onset. In fact I concur with @bobbler that it felt like it caused a some kind of muscle damage to even try.

To me that is no different to telling your doctor/sports physiotherapist where it hurts. Athletic training is a real education about your own body and teaches you what to expect normally from organised exertion which pushes comfort zones based on science. When this process no longer happens after ME onset it is self evident unless one has not been through sport exercise training beforehand.

Sports science based coaching tries to inform athletes about their own body based on the discoveries of empirical science. Of course this proceeds on a basis of statistical norms rather than the expectation of pathology or anomaly, so that is a reason to be circumspect but where experience correlates with science based prediction there is no reason to doubt it. e.g. reduction of available muscle and blood oxygen after about a minute of maximum exercise (which the likes of Roger Bannister and his coaches and many since have studied), causes pain during the activation of anaerobic respiration with corresponding sense of weakness and desire to rest to replenish oxygen, which you have to resist to improve anaerobic capacity and oxygen debt recovery. Going through that process deliberately and with psychological preparation improves ones awareness of the processes involved, self control and awareness of such sensations. Ultimately it should lead to improved performance due to cardiovascular development etc which comes when you push the envelope systematically and repeatedly over a long perod especially when in a youthful growth phase when plasticity is highest.

It does hurt, which is why Sir Steve Redgrave famously said words to the effect "if anybody sees me go anywhere near a boat again, you have my permission to shoot me.” It is in the nature of pain to cause aversion. It is also potentially dangerous for people who do have physiological anomalies other than ME, to stress their body that much.

About anaerobic pain, the devil is in the detail once again. I did not mention anaerobic pain above but discussed it elsewhere in relation to not ending up bed bound, which I attribute to being active despite ME pain, which I attribute to previously learning to face the anaerobic pain barrier and developing some pain tolerance when training for rowing (plus possibly cardiovascular development). It is important not to confuse that with the suggestion ME pain is anaerobic respiration. I do not know that or claim to, though the aches seem comparable on the face of it there is not enough science to confirm this and aches are pretty nonspecific sensations.

This boils down to the thing about class errors, melon is a fruit but not all fruit are melons, classwise anaerobic training is painful but not all pain is anaerobic training. Pain can be of an unknown cause and yet still sensed and not allowed to prevent activity if one has pain tolerance. Doesn't mean it is good for you. With healthy anaerobic training it normally is of course but with ME it definitely isn't and causes ghastly PEM symptoms, this I know because I tried and would not advise it.

Does that make sense?

 

That's interesting. I had a consistent 24 hr delay regardless of the type or amount of physical exertion. Different triggering mechanisms?

 

I meant the quicker the tipping point is reached, where PEM happens as opposed to getting away with it.

Though that said my PEM does not always behave the same. The other day for example I had what I think was PEM headache on waking the day after 20 mins weeding my back yard around 4pm and the PEM headache then departed 4pm on the same day, 24 hrs after the exertion which I think caused it. It still has a circadian element but not like the usual where I feel iller 24 hours after exertion and that then lasts 24 hours.

Its all very odd.

 

My n=1. Power walking for 40-50 minutes spread out once or twice a week when I'm feeling particularly good= no delayed PEM.

Power walking over 60 minutes once a week=guaranteed delayed PEM.

Took years to figure this out- trial and error.