From Function to Physiology and Back in Adults with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling health condition consisting of multiple signs and symptoms spanning many body systems. Post- exertional malaise (PEM) is a hallmark of ME/CFS inappropriate loss of physical and/or mental stamina in response to physical or cognitive exertion, consisting of rapid physical and/or mental fatiguability accompanied by a tendency for other associated symptoms to worsen. Signs and symptoms commonly associated with PEM include cognitive dysfunction, immune hyper- or hypo-functioning, neurological sequalae, pain, and gastrointestinal disturbances are commonly associated with PEM. There is frequently a prolonged length of time to recover from PEM exacerbations, which are often characterised by substantial impairments in daily function. PEM/PESE is best understood in the context of ME/CFS, however the recent emergence of Long Covid and associated ME/CFS has added relevance to efforts to improve our collective understanding of PEM.
The presented thesis contains data from eleven publications pertaining to ME/CFS and PEM since 2012. Novel data from these publications elucidated the clinical recognition and underlying physiology of PEM, as well as applied these findings to medical and legal practise. PEM involves an abnormal constellation of symptoms and signs during the recovery period from a standardised physical stressor, which may be used by clinicians and researchers to differentiate PEM from deconditioning. People living with ME/CFS have significantly lower V̇ O2 and work rate measurements at the VAT than deconditioned individuals. Medical and legal practise guidelines were composed and interventions (e.g., IV saline and HRM) were evaluated based on foundational information of the underlying physiology of PEM/PESE presented in this thesis.
The publications contained in this thesis have created a stable foundation for future investigations and innovations in research and clinical practice in ME/CFS.

Date of Award	19 Jan 2024
Original language	English
Awarding Institution	University of Portsmouth
Supervisor	Zoe Louise Saynor (Supervisor) & Ant Shepherd (Supervisor)