Rapid response to a British Journal of Sports Medicine discussion article on PEM and long covid

The British Journal of Sports Medicine (BJSM) published earlier this year a discussion article by Charlton and coauthors challenging the assumption that cardiovascular deconditioning explains long covid, and arguing that post-exertional malaise (PEM) — the cardinal and defining feature of ME/CFS — plays a central role in a sizeable subset of long covid patients.

I submitted a rapid response to the journal, highlighting a few concerns I have, whilst welcoming the authors’ rejection of the deconditioning model and focus on PEM.

In brief, I am concerned that PEM — now a much more mainstream ‘concept’, owing to its presence in a significant subset of long covid patients — is frequently being conflated with exercise intolerance in the long covid literature. PEM has to be correctly identified in all clinical and research settings; its presence not only helps identify an ME/CFS phenotype or patient subset, but also should determine, to a large degree, which treatment and care approaches are appropriate or not.