Journal or Book Title
Fatigue: Biomedicine, Health & Behavior
Background: Consensus for an operational definition of post-exertion malaise (PEM) and which symptoms best characterize PEM has not been established and may be due to variability within and between studies.
Purpose: Determine the magnitude of the effect of maximal and submaximal physical exertion on multiple myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) symptoms that are associated with PEM and explore variability among two studies in which mood, fatigue, and pain symptoms were measured before and after exercise.
Methods: Symptoms were measured before, and 48 and 72 hours after exercise in study 1 (ME/CFS = 13; Controls = 11) and before and 24 hours after exercise in study 2 (ME/CFS = 15, Controls = 15). Between-study variability was examined by comparing Hedges d effect sizes (95% CI) from studies 1 and 2. Within-patient group variability was examined via inspection of dot density plots.
Results: In study 1, large increases in general fatigue (Δ = 1.05), reduced motivation (Δ = 0.93), feelings of fatigue (Δ = 0.90), feelings of confusion (Δ = 0.93), and total mood disturbance (Δ = 0.90) were found at 72 hours. In study 2, a large increase in affective/sensory pain (Δ = 0.79) was found at 24 hours. Dot density plots in both studies revealed substantial variability among people with ME/CFS relative to healthy control participants.
Conclusions: PEM symptoms are variable among people with ME/CFS and several gaps in the literature need to be addressed before guidelines for measuring PEM in the clinical or research setting can be established.
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Taylor and Francis Online
Lindheimer, Jacob B.; Meyer, Jacob; Stegner, Aaron J.; Dougherty, Ryan J.; Van Riper, Stephanie M.; Shields, Morgan; Reisner, Amanda; Shukla, Sanjay K.; Light, Alan R.; Yale, Steven; and Cook, Dane B., "Symptom variability following acute exercise in myalgic encephalomyelitis/chronic fatigue syndrome: a perspective on measuring post-exertion malaise" (2017). Kinesiology Publications. 42.