The timeline of post exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome : a thesis presented in partial fulfilment of the requirements for the degree of Master of Sport and Exercise in Exercise Prescription and Training at Massey University, Manawatu, New Zealand
Open Access Location
PURPOSE: To investigate the timeline of post-exertional malaise (PEM) using objective and subjective measures in Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The primary aim was to determine whether PEM extends beyond 24-hours, and if a 48-hour or 72-hour repeated exercise protocol would provide additional information as a diagnostic tool. The secondary aim was to analyse subjective patterns of fatigue during PEM. METHODS: Sixteen ME/CFS and 16 age and gender matched controls participated in the study. Participants were randomly assigned to either a 48-hour or 72-hour repeated cardiopulmonary exercise test protocol on a cycle ergometer. Objective measures were recorded at anaerobic threshold (AT), respiratory exchange ratio (RER) and maximal exercise. All ME/CFS participants recorded their subjective fatigue 7-days prior to and 10-days post exercise utilising the daily diary of fatigue. RESULTS: Results from the 48-hour and 72-hour protocol indicated no decline in functional capacity in any group across days. There was a significant increase in workload and %VO2max at AT within the 72-hour ME/CFS group only. Subjective timelines of fatigue showed significant differences between the 48-hour and 72-hour protocol, with the 48-hour ME/CFS group taking significantly longer to recover (mean 11 days) than the 72-hour ME/CFS group (mean 5 days). Conversely, both control groups were recovered in less than a day. However, there was high variation across measures of subjective fatigue among ME/CFS participants. CONCLUSIONS: The results of this study further support the use of 24-hour repeated protocols to determine functional decline during PEM. Results also provide new information regarding a potential improvement in function 72-hours after an initial exercise bout in ME/CFS. Subjective results indicate no identifiable pattern in relation to subjective fatigue during PEM. Future research should focus on a larger clinical trial to further understand the implications and consistency of the data from this study.
Myalgic encephalomyelitis, Chronic fatigue syndrome -- Diagnosis, Chronic fatigue syndrome -- Symptoms, Exercise -- Physiological aspects, Exercise tests