Prof. Betsy Keller Video:
PEM – strategies for determining and managing the cardinal symptom of ME/CFS
This was a presentation at a recent Swedish scientific conference:
I don't think this paper has been posted yet, but it's a good review of the studies that look at CardioPulmonary Exercise Tests (CPET) to document PEM/exertion intolerance in ME.
Cardiopulmonary Exercise Test Methodology for Assessing Exertion Intolerance in ME/CFS (Stevens et al., 2018)...