Describing the relapsing of disease symptoms following physical or mental activity a “crash” or “hitting the wall”. The biomedical field describes this characteristic and hallmark feature of ME/CFS as post-exertional malaise (PEM) – a term that grossly understates the debility that comes with this disease-defining symptom.
Post exertional amplification of symptoms in ME/CFS patients, a hallmark symptom of damage to the aerobic energy system means that it is utterly counter productive to try to use aerobic exercise, such as graded exercise therapy, to improve health as directed by NICE guidelines.
Betsy Keller at Ithaca College research titled, “Inability of myalgic encephalomyelitis/chronic fatigue syndrome patients to reproduce VO2peak indicates functional impairment.” Keller used a 2-day cardiopulmonary exercise test (CPET) to show that physiological values in ME/CFS patients worsened on the second CPET, a phenomena unique to ME/CFS patients.
The Dutch Vermeulen team’s article titled, “Decreased oxygen extraction during cardiopulmonary exercise test in patients with chronic fatigue syndrome” They used CPET to show that oxygen extraction – or the ability of oxygen to be removed from the blood and used by tissues to support metabolism – was significantly lower in ME/CFS patients and could be a causal explanation for exercise intolerance in ME/CFS patients.
Mark VanNess at the Bristol Watershed after a screening of "Voices from the shadows"
Dr Nigel Speight at Bristol Watershed