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Adrienne Dellwo

Exercise & Pain Thresholds in Chronic Fatigue Syndrome

By November 8, 2010

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Research Brief

New research supports earlier findings that people with chronic fatigue syndrome (ME/CFS) develop amplified pain after exercise, while healthy people do not. The latest research also showed differences in the exercise/pain response between ME/CFS and chronic low back pain.

For decades, researchers have been trying to understand a key symptom of chronic fatigue syndrome called post-exertional malaise (PEM). It's an abnormal physical reaction to exercise that causes symptoms to heighten. While most people will get an energy boost from exercise, people with this condition will become intensely fatigued, feel increased flu-like symptoms, and often experience body-wide pain. PEM generally last for at least 24 hours, and can last for several days in some people.

This study looked at just the pain levels and not the other aspects of PEM. Researchers discovered that when participants with chronic fatigue syndrome exercised within their physical limits, their pain thresholds dropped, causing them to feel pain more easily. (The pain threshold is the point at which sensation, such as pressure or heat, is interpreted by the body as pain. It is not the same as pain tolerance.)

Researchers concluded that chronic fatigue syndrome involves abnormalities in what's called central pain processing. That means the central nervous system (brain, spinal cord and associated nerves) reacts strangely to signals and essentially "turn up the volume" of pain. This is called hyperalgesia.

Hyperalgesia is one of the defining characteristics of the related condition fibromyalgia.

This year alone, at least 5 published studies have explored aspects of PEM. Of those:

Meanwhile, several researchers are looking for unique biomarkers of PEM in the hopes of finding an objective way to diagnose ME/CFS.

Does this research match your experience? What is post-exertional malaise like for you? How much exertion does it take to trigger it? Leave your comments below!

Learn more or join the conversation!


Photo Michael Greenberg/Getty Images

November 8, 2010 at 7:08 am
(1) Gareth says:

As you mention the relationship between Fibromyalgia and hyperalgesia does that mean that post-exertional malaise (PEM) is recognised as being part of Fibromyalgia? I ask as it is something I completely recognise. I know my Fibro is relatively moderate and I try to keep going but this PEM or something similar seems to hit me

November 8, 2010 at 8:00 am
(2) barry says:

Absolutely fits with my experience. A few minutes or even seconds into exercise and I hit the pain barrier, and the more I try to push through the barrier the more I pay for it the next day in terms of lacking energy.

November 8, 2010 at 8:45 am
(3) Beth says:

CFS symptoms last for days after exercise or just getting around town. My can do attitude will get me in trouble.

November 8, 2010 at 9:49 am
(4) Nancy A. says:

I’ve had fibromyalgia for 24 years and I lead a very sedentary lifestyle. I was approved for Social Security Disability two years ago. This summer, I thought I’d give water exercise a try, under the supervision of a physical therapist. I only lasted one session of about 30 to 45 minutes. I was sore for a week afterwards. It’s so discouraging to have these flareups. The most “exercise” I’m able to do is light housework and grocery shopping once a week. I’m 57 and feel more like 87.

November 8, 2010 at 10:04 am
(5) Agatha says:

Post-exertional malaise in CFS can be really extreme. Over the course of 6 years of illness, I have three times over-exerted in a way that put me in bed for nearly a year each time. It can take me many, many months to regain the strength that I lose when I overdo. I also have lower-level setbacks from overdoing, some lasting a day or two, others a couple of weeks. But sometimes when I push past my “energy envelope” too much, I pay for a very long time! That’s by far the worst part of the illness for me.

November 8, 2010 at 10:05 am
(6) Fran says:

I am struggling with this now. My physical therapist is trying to strengthen my left side to improve my balance. I can only do a few of the exercises without PEM. This morning I am aching before I start and have decided to back off for the day and begin again when the PEM decreases taking it still more slowly. It is a dilemma but if I give up, I will become still weaker. So I continue to try a few exercises at a time, holding yoga poses one more breath, sometimes practicing only parts of an exercise until I slowly am able to perform a few repetitions. Despite the PEM and consequent poor exercise performance, I am doing better than if I just gave up. I hope they find some help for us soon. Thanks for the guide Adrienne. You are doing us all a world of good.

November 8, 2010 at 11:17 am
(7) judie says:

I can truly relate to the PEM diagnosis after exercise. After 9 years of FM, CFS and a weight gain of 40#(typical of FM patients) I am going to try again! Extra weight exaserbates the symptoms;trying to loose it means exercise; exercise results in PEM;PEM results in less exercise and movement;and so it continues again, and again, and again…….. but I’m not giving up! Starting out slow and trying to adjust the movement to the “where the pain is of the day”.

November 8, 2010 at 1:10 pm
(8) Heidi says:

Unbelievably absurd! It’s still like they completely don’t understand our condition ! To still be scratching their heads at how we can’t excercise like healthy people-ridiculous! Get a move on people start doing some real research, instead of just collecting your research money!
We have a very serious disease that completely changes our lives, we need some real help, start finding the answer to the cause! So nobody has to have this anymore, then a cure.

November 8, 2010 at 8:11 pm
(9) kev says:

I must say I don’t fit the fibromyalgia category (Thank God!) feel for those that have this but I do fit the CFS catgegory, having said this I was an elite athlete when this all came about and 3years on I can at times go out and ride my bike reasonably long and hard still but it certainly flares all of the symptoms and leaves me unable to think about riding for days or even a week, sometimes I get away with it more lightly and other times it hits me hard. Fatigue worsens, balance worsens, brain foggy/groggy, slightly different sort of dull headache quite often accompanies the brain fog, worsening of my vision (Accommodation difficulties). Please bare in mind I once was able to compete as a cyclist on the world stage, I was able to train between 700-900km’s a week week in week out and yes I did get tired at times but recovered and never had the balance, cognitive symptoms etc…I must say riding doesn’t affect my balance as coordinating walking (I find this extremely weird).
Anyway I won’t go on anymore but say that the researchers… around the world serious about cracking this rotten nut should be contacting Associate proffessor Donald Staines to discuss his theory “Postulated vasoactive neuropeptide autoimmunity in fatigue-related
conditions”: A brief review and hypothesis

Gold Coast Public Health Unit, 10-12 Young Street, Southport, Qld 4215, Australia

November 9, 2010 at 4:33 am
(10) Darren kinvig says:

This stuff makes sense to me. I wish there was a voice out there that new how to put it into words better than reports. I may decide to do that for people. I suffer from this and to feel it is not to research it. TO be a patient is not to be a researcher.
I am going to develop a vocabulary for people that suffer with pain. Plethora of pain.

November 9, 2010 at 7:44 am
(11) Jane says:

One of the points in the article suggests that when CFS patients are experiencing PET they feel more pain then a healthy person. (or did I misunderstand?)

Whereas I feel high levels of pain in specific areas (arms, legs, right side of trapezius), I do not have any unusual responses to pain anywhere else.

To me that suggests it is not the body interpreting pain unusually, it’s that those specific areas hurt.

November 10, 2010 at 6:37 am
(12) Christene Herbing says:

I found the article very interesting but after suffering with FM and CFS for the last 2 years I have found that if I exercise a little bit each day and vary my exercises, I have been able to extend my time doing so. As I am a dance teacher FM nearly put me out of business but I have tried everything to keep me on the dance floor. I have had to except that pain is the norm to me and try and put it out of my mind while I dance. I found regular exercise to be more helpful than no exercise as long as I do my stretching exercises before and after I dance. If I don’t stretch, I jam up and turn into a painfull mess within a very short time. This as we all know, turns into a bad night sleep, twitching legs and an even worse next day.

November 10, 2010 at 6:58 am
(13) olivia says:

I surely do appreciate especially Fran and Christine’s comments!
I haven’t figured out how to avoid physically feeling like a truck ran over me, but I know I feel mentally worse if I do not move about and try to raise the bar in some sort of gentle activity [walking, yoga, etc.] a couple times a week. I don’t care for the alternatives – letting muscles become more unwilling/useless and becoming more depressed mood due to lack of ‘good’ brain chemicals being stirred up.

November 10, 2010 at 3:37 pm
(14) Rachael says:

People who suffer from CFS often talk about running on empty. There is a link between dopamine and immune system, but there is another link between endorphins levels and immune system. It seems autoimmune disorders are linked to low levels of endorphins. Could CFS be caused by an dopamine/endorphin deficit?

This article posted by Adrienne was very informative regarding the role of dopamine in CFS.

Dopamine in Fibromyalgia & Chronic Fatigue Syndrome
By Adrienne Dellwo


November 11, 2010 at 6:15 pm
(15) Adrienne Dellwo says:


PEM isn’t technically recognized as a fibromyalgia symptom. While fibro can cause an extreme reaction to overexertion (and it may not take much to overexert us), we don’t have the extreme crash and PEM symptoms resulting from exertion that’s well within our limits.


November 12, 2010 at 5:03 pm
(16) Delene Jonker says:

In the past I worked myself into the ground, trying to deny that I am wasted and to proof to myself that I am not a failure! I surely felt that way, when drs told me it is all in my head, there is no such thing as CFS and FM cannot be proven. I shall work out in the pool and gym and sauna the works for 2 hours, then come home, climb into bed and sleep for hours!! My head is so foggy that I drive my car into casual accidents, with clients with me in the car. I became afraid to allow them into the car with me. I am always sleepy, tired and foggy.Bad memory and concentration, I cannot even entertain friends, too tiring. I suffered years now, without being diagnosed, I research on the net and came to conclusions. Where can I find a proper dr to diagnose me? I put on 40kg after I broke my leg and 3 operations to my neck, shoulder and jaw- to release the chronic pain!!! I feel like giving up, the depression is very severe. I am so ashamed when I cannot even walk with my family to do shopping, to tired and too much pain. I feel so old ugly and slow. I am also very emotional and cry easily for no reason. I stopped working because I could not stay ahead of the pack any longer, I lost income because I am not physically capable to drive, walk. talk, attend meetings etc. Then people blames me for being lazy. I am at home now for 2 years and takes it very slow, I do not partake in anything socially anymore, no energy for that. My mum and in-law’s are over 80 and much more alive that me. How can I make them understand that I truly am ill? They ego the drs that there is no such illness as FM and CFS. Thanks for sharing.

November 12, 2010 at 5:50 pm
(17) Justin says:

I have been suffering with mild CFS for 4 years now. I was finally diagnosed 2 years ago. Most weeks I can work full time now but occasionally I will have to take a day off. I was a keen rower before I got ill now I just Cox. If I do any exercise I’ll develop a dull headache with in minutes followed by a stiff neck, dizziness and cognitive problems. The next morning I will wake up and be fine, but by late morning I will be back in bed. I don’t get the endorphin high I used to get after training. For me PEM is by far the most debilitating symptom of CFS. Understanding the cause of PEM should help to understand CFS and maybe Fibromyalgia.

November 12, 2010 at 9:34 pm
(18) L says:

If you can do a little bit of exercise daily,i.e.,2 – 3 minutes at one time or more if you can, it’s better to do it right before bedtime. Since most of us feel totally exhausted and are in a huge amount of pain after any exercising, going to bed right afterwards makes sense. I literally collapse from any exercise, so if I do any at all I can then fall into bed and hopefully feel a little bit better by morning. That doesn’t always happen, but it’s worth a try…even if it’s only for 30 seconds at first!

November 13, 2010 at 4:25 am
(19) Mary T. says:

I experience PEM, too. I try to go to water therapy at the nice warm Easter Seals pool twice a week, but sometimes I can only make it once. I drive 40-50 mins round trip to spend 15-20 mins in the pool. By the time I get home the back spasms have started, so I take a long hot shower. I’m sore the next day (but not ‘crippling’ sore) and day 2 and 3 I do nothing but sleep. It’s just exhausting. Same as if I run errands – 2 days later it hits me. It makes me wonder if the pool time is worth the ‘down time’ that I have? I’m seriously considering giving up the pool, although the water feels wonderful while I’m in it. Maybe if I just get one of those floaty-lounge-chair things and a margarita, rather than trying to exercise, I’d be better off.. at least there would be a smile on my face!! LOL!

November 13, 2010 at 12:41 pm
(20) Karen says:

I have joined an exercise facility and after a few months quit. I would go, and then come home and nap, and try to go the next day and be to tired. So I would go a couple of times of week, but found myself “down” more than “up”. I thought my pain was due to muscles not being used. While I am over weight, and my primary care and immune specalist keep saying you need to lose weight, I feel like I am up against a wall, cause it is so hard to exercise, or even take a walk.

I might go away to a hotel with family for a few days in the summer, and splash around in the pool, and then come home and have to recover from the pool activity for a few days. I agree with Mary T, the floating thingie in the pool and a margarita would be the way to relax and enjoy.

November 13, 2010 at 3:53 pm
(21) edwards29 says:

Twenty years ago, I was able to exercise on machines in a gym about an hour three times a week. As I’ve grown older and my condition has worsened (CSF) over the past 36 years that I’ve been ill, I’ve gradually cut down on exercising to the point where now I don’t exercise at all. It’s strange, because sometimes I feel better after moving around a little, and other times I feel worse. I usually feel horrible after grocery shopping each week but feel much better after a night’s sleep. I definitely need 8 hours of sleep each night to keep me moving in the daytime. But mostly I sit in a chair with my laptop or lie in bed reading the paper or watching TV. This can’t help but lead to premorbidity.

November 14, 2010 at 9:05 pm
(22) Heidi says:

Hang in there Delene! You are a very strong person for enduring what your going thru! That’s something to be very proud of, not everyone understands chronic conditions like ours.
I feel the same way, also very sad that they don’t have better answers for us!
It’s a shame because if they did people would understand what we’re going thru.
I complain a lot about the so called experts but Please Don’t give up hope for a cure!

November 15, 2010 at 5:34 am
(23) Sharon Levin says:

PEM, again because of the CNS/ANS/Cerebral Spinal column FLUID that houses the AMINO ACID chain- we should have 12 (8 ESSENTAL) but have 4 ‘working’ and 4 definately that dont – L-Theanine, L- Taurine, L-Tyrosine, DL-Phenelalanine – these affect anxiety, panic, fatifue, thyroid function and correct pain-balancing receptors. Quite alot to HAVE TO REPLACE WITH 1- MADE TO CELLULAR ADAPTABILITY SUPPLEMENTATION, and 2, exercise within the CFS and FM sufferers ability – too much is overkill and can also lead to Adrenal Fatigue – too little/nothing is really asking for more trouble- after 23 years of suffering from both +ME and Adrenal Fatigue – and now in remission, studying, learning all the time – myself being the 1st ‘researching crash-test dummy’ and then either agreeing or disagreeing on solid grounds with my peers in research who suffer/ed with same illnesses, I am certain, working with patients in rehab physiatry, clinical nutriton, supplementation (homeopathic, functional medicine, herbal adaptogenics), that this correct combonation, together with rest when appropriate, corrected sleep patterns, teaching medication and relaxation skills and using all modalities myself for many years, decreased PEM occurs and in the minority of cases, INCREASE. Our conditions are with us for life – it is up to us to find the right help, eat really correctly for the condition, find total BALANCE, no matter what other stressors ‘we allow (with characteristic trait of self-victimisation which must be addressed as well), to find the strength and determination of MIND/BODY connection, to become stronger, not give away energy EVER unnec’ily and BELIEVE IN OUR OWN SELVES – whatever the circumstances. Sharon Levin http://www.fibromyalgiasa.co.za. With blessings to all for wellness, beginning now into New Year and beyond

November 16, 2010 at 7:44 am
(24) Gareth says:

thanks for the clarification Adrienne. I feel dearly for those of you that are suffering so much.

November 22, 2011 at 3:18 pm
(25) Kendall says:

I have been experiencing this for years in relation to my chronic fatigue. Every time I exercise, the next day I am in extreme pain all through my body – not just the muscles that I worked. I try very hard to stay “within my limits” and wondered if this was just from not having exercised during the extreme fatigue phase, although I always kept trying to do something so as not to get too out of shape.

I now appreciate that the pain is not because I left off exercise it is just part of the condition and an extremely unpleasant one at that! Haven’t seen suggestions for what to do to ease the pain. At this point, I just take pain medication, gabapentin and amitriptyline at night and hope for the best!

March 6, 2013 at 10:34 am
(26) Nic says:

My pain is all over. It feels skin deep, like your skin feels when touched when you have flu, only I don’t need to be touched to feel it. I do get joint pain too. It comes on whenever it feels like. I only have to do housework or less at times for it to come on. Other times I can do much more exertive exercise with less come back. There doesn’t seem to be any rhyme or reason to it. I don’t know how to avoid it or manage it. I take Zapain when it wears me down. When it’s bad I lie down and this helps after a while. Mostly, the pain’s not there when I’m doing something, it’s after. Anything from a minute to a day after.

April 24, 2014 at 7:50 pm
(27) Kendall says:

I have had CFS and fibromyalgia for 7 years now. At first, exercise was not an option. Now, I am able to exercise a bit, but I experience both flu-like pain symptoms and severe muscle and nerve pain for 2-3 days after a 30 minute exercise routine which is primarily yoga with some weight and resistance training. For some reason, the pain is now getting worse and lasting longer and so I am exercising less. Interested in how people manage the pain as thus far I have only found pain killers to work.

May 19, 2014 at 10:24 pm
(28) __________________________ says:

Terry O’Brien of Back Trouble UK says “While 80 percent of the population are likely to experience low back pain at some stage in their life, there is a worrying trend in the amount of back pain experienced by teenagers. If a nerve root is brushed by the discogram needle, the nerve root can become irritated causing pain, which will almost always go away quickly. It is important that you take extra care while performing your job duty.

Also visit my web-site … <a href=”http://www.robot.url.tw/main/userinfo.php?uid=96564″>__________________________</a>

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