Trial By Error: Why Are Exercise Studies for Long Covid Still Failing to Address PEM Adequately?

By David Tuller, DrPH

Note: I posted this on March 29th, and for some reason it disappeared from the site–so I am reposting it today.

I have written previously about the issue of exercise studies for long Covid patients. As with the discredited PACE trial for the illness or cluster of illnesses currently being referred to as ME/CFS, the theory behind these studies posits deconditioning as a central cause of patients’ disability. This approach tends to overlook the phenomenon of post-exertional malaise (PEM) or post-exertional symptom exacerbation (PESE), which is characteristic of ME/CFS and reported by many patients with long Covid.

When such studies do mention PEM/PESE, it is not clear they have properly distinguished it from the tiredness that often accompanies exercise and is exacerbated in those who are in fact decondition. In December, for example, I wrote a post about a study called “Effect of using a structured pacing protocol on post-exertional symptom exacerbation and health status in a longitudinal cohort with the post-COVID-19 syndrome.” Among many other methodological issues, some of the PEM episodes documented lasted just one to three hours. Were these examples of PEM, or just standard fatigue?

In 2015, a report from the Institute of Medicine (now the National Academy of Sciences) identified PEM as characteristic of the illness, although it renamed it “exertion intolerance.” The US Centers for Disease Control and Prevention identifies PEM as a significant factor in developing treatment strategies. Since the emergence of long Covid, PEM has received widespread news coverage. The New York Times published this story by journalist Melinda Wenner Moyer on exercise and long Covid more than a year ago. And Zeynep Tufekci, a sociologist and Times columnist, highlighted PEM in a compelling piece about last fall’s ME/CFS protest at the White House.

Yet many researchers and clinicians still seem not to understand the importance of this symptom. Since last fall, the National Institutes of Health’s RECOVER Initiative, which was set up to investigate the long-term effects of Covid, has been embroiled in a bit of a controversy about a proposed exercise study, highlighted in an announcement page of planned research. Few details of this study, including the study protocol, have been made publicly available.

Long Covid advocates have been seeking more information about the proposed study, and #MEAction has also raised concerns, sending a letter to RECOVER last month. After receiving no response, the organization sent a follow-up letter last week.

Here’s a key paragraph from the latest letter:

“People with Long COVID who meet the criteria for myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) and those with post-exertional malaise (PEM) must be excluded from this study. There is no justification for using exercise therapies designed for patients who do not have ME/CFS or PEM on a Long COVID population with ME/CFS or PEM.”


And now a PEM-less “exercise reporting template” for long Covid

And now the journal Archives of Physical Medicine and Rehabilitation has just published an article called “Exercise Reporting Template for long COVID Patients: A Rehabilitation Practitioner Guide.” The article touts the merits of the Consensus on Exercise Reporting Template (CERT), a 16-item checklist “that reports on the quality of the exercise interventions in the management of acute and chronic conditions.”

Ok, then. Here are some of the key points related to prescribing exercise for long Covid:

Exercise is associated with improved immune system function, psychological and mental health, neural plasticity (healing of the nerves in the brain), reduced pulmonary (lung) complications, and enhanced cardiovascular (heart) outcomes.”

“Most patients presenting with long COVID can begin with supervised breathing and light exercise programs in the early phase of rehabilitation in the clinical setting. Using the 6-20 rating of perceived exertion scale, it has been recommended that patients commence exercise as low as 6 to 8, ranging from ‘no exertion’ to ‘extremely light’ and then progressing by ∼2 to 3 points on the scale every week as tolerated.”

“Although exercise promotes good health despite the health condition, sedentary patients and those with existing chronic medical conditions should undergo medical examination and approval before starting an exercise routine.”

The article makes no mention of PEM/PESE, and that’s a major problem. No one seriously disputes that exercise in general is beneficial, but it is critical to remember that it can be contra-indicated in those with PEM/PESE. In other words, it can cause harm.

No ”exercise reporting template” for long Covid is acceptable if it fails to include a recommendation of rigorous pre-screening for PEM/PESE. Since many patients themselves might not be aware of this symptom and might not understand why their efforts to improve were being met with serious setbacks.

When it comes to any form of “rehabilitation,” patients with and without PEM/PESE should obviously be handled differently. Everyone involved in treating and researching long Covid patients should be aware of this. After all, we have now been dealing with this for years.

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