Summary of the NIH’s exploration of post-exertional malaise

The research team that is studying ME/CFS at the National Institutes of Health (NIH) has just published an interesting paper on post-exertional malaise (PEM). They formed focus groups and listened to patients’ experiences to better understand PEM.

The authors write: “Historically, measurement of PEM has had considerable controversy, and patient groups have felt left out of the process by which policy makers develop definitions of ME/CFS”. In my view, listening to patients’ experience should always be the first step in medical research. So I’m happy to see these kinds of projects published.

In this study, 43 persons with ME/CFS participated in nine focus groups. For 5 out 9 focus groups,  ME/CFS patients were recruited who had undergone a CPET evaluation and prompted them to report their recall of the symptoms following the CPET evaluation. The article is open-access and available in the link below.

The results can be summarized as follows

I) Different types of triggers

First: PEM is not only triggered by exercise or physical activity but also by cognitive or social activities and sometimes (emotional) stress. A conversation with a friend or a to the grocery store can be triggers of PEM.

II) A compounding effect

Second, the authors note that with PEM there is a compounding effect: it’s not about one activity but the sum of many:“When focus group participants were asked to describe PEM following exertion, many expressed the importance of understanding their ‘starting point’ or ‘baseline.’”

Participants explained how successive exertion can compound symptoms which makes it difficult to study PEM. Participants for example said they felt already worse before the start of the study because of the travel to get to the testing site.  

III) Wide symptom range

Third: PEM had a wide symptom range. Patients described PEM as all-encompassing with symptoms affecting every part of the body. A couple of symptoms, however, were often reported: exhaustion, difficulty thinking clearly or paying attention, muscle pain/aches, and muscle weakness.

Participants explained that the exhaustion from PEM is different than what they experienced before. One person said:

“I used to be an athlete. I had a very intense job. So I would feel a lot of fatigue from those activities. But this is not that type of fatigue. This is a type of fatigue I felt when I rarely got the flu, years ago. Only that flu lasted for a few days and not for the years they have now.”

Muscle weakness was also a notable symptom. One participant said: “my legs were getting so weak they were shaky as if I had just run 10 miles.”

While not as commonly mentioned as the three core symptoms, many participants described sensitivity to light, sound, and smell as part of PEM. One person said: “I have to put on earphones. I need to block the sound. I wear a mask to block the light, wear sunglasses.”

IV) PEM after CPET versus PEM in daily life

Although the reported symptoms were similar, PEM reported after CPET came on quicker and was more severe than PEM in daily life.

V) Delayed onset

Fifth: onset patterns varied but most participants perceived a delayed onset of symptoms, with nearly half reporting symptoms beginning 12–48 hours after exertion. The authors write:

“Interestingly, 11 focus group participants described experiencing an adrenaline rush while doing an activity before the PEM symptoms came on, both in daily activities and during the CPET. These participants described experiencing ‘adrenaline,’ ‘endorphins,’ and ‘euphoria.’”

In my view that’s an important point because it differentiates PEM from the aches and symptoms unfit persons experience when they try to exercise more. It also makes clear that PEM is not about disliking exercise or discomfort during or immediately after physical activity.

VI) Complete rest is necessary

A sixth conclusion is explained in this quote from the paper:

“When asked what could alleviate PEM symptoms, virtually every participant agreed that while in an episode of PEM, complete rest was absolutely necessary to reduce symptoms. Many participants emphasized that this was not a strategy so much as an outcome. For these participants, complete rest was a “demand from the body.”

In other words, patients didn’t want to rest; they simply had to.

One participant said:

“Complete rest is really the only thing that can facilitate a recovery for me. Basically, I have to stop and put things on hold because I realize when I am weakened with PEM, if I push through. . . I will end up making the symptoms worse, like going downhill really fast.”

Other participants said: “If I’m already in PEM and overexert, I feel the effects instantly and more intensely, and it lasts deeper and longer.” Another said: “It’s not just an add-on it’s a multiplier. It’s like an exponential effect on it.”

When asked to describe what ‘complete rest’ entails, most participants described lying down ‘absolutely flat’ and with as little sensory input as possible. For many, this included ear plugs, darkness, and solitude.

VII) Pacing

Seventh conclusion: planning and moderation of energy expenditure was essential to avoiding PEM but patients described it as difficult and tentative. Many took years of overexerting and “crashing” before learning better how to manage ME/CFS.

VIII) enormous disability and dispair

The eighth and last conclusion: PEM created enormous disability and despair. “Focus group analysis revealed an inability to live a “normal” life as a core aspect of the PEM experience as described by patients.”

One person said:

“I feel like I’m just constantly assessing my energy level, and normal people don’t do that. They get up in the morning and they pretty much know that they can get through a list of things to do, whereas it can take me weeks to get two or three things done, sometimes none at all.”

3 thoughts on “Summary of the NIH’s exploration of post-exertional malaise

  1. Dean says:

    We all know this. Show me the money!!!! Where the hell is the dam therapy to lesson this nightmare!
    I told my wife this morning I am getting worse. I will be dead before a cure.


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