Elevated Perceived Exertion in People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: A Meta-analysis

Abstract

Purpose Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM) are two debilitating illnesses primarily characterized by chronic symptoms of fatigue and musculoskeletal pain, respectively. Some investigators have observed an elevated sense of effort in these patient groups; however, this effect has not been substantiated via quantitative review. As such, we conducted a meta-analysis of RPE responses to aerobic exercise in ME/CFS and FM compared with healthy adults. Methods Case–control studies involving adults with ME/CFS or FM that measured RPE and heart rate responses to acute aerobic exercise were included. Data sources included PubMed, Scopus/Embase, CINAHL, CENTRAL, and Google Scholar. Risk of bias was assessed by evaluating each study’s description of participant characteristics, matching procedures, and administration of RPE scales. Hedges’ d effect sizes for RPE were calculated and aggregated using random-effects models, and potential moderators were explored with meta-regression analysis. Results Forty-one effects were extracted from 37 studies involving 1016 patients and 686 healthy controls. We observed a large (Hedges’ d = 0.85, 95% confidence interval = 0.62–1.08) effect indicating higher RPE in patients than controls. The mean effect size was significantly moderated (P < 0.001, R 2 = 0.38) by whether RPE data were analyzed at a peak or submaximal intensity (b = 0.60, z = 4.6, P < 0.001) and the type of patient group that was studied (b = 0.25, z = 2.08, P = 0.04). Conclusions People with ME/CFS and FM perceive aerobic exercise as more effortful than healthy adults, but the exact causes are unclear. The large magnitude of this effect merits further exploration of underlying mechanisms that could provide insight into the pathophysiology of ME/CFS and FM or the broader debate about the nature of central and/or peripheral signals that influence RPE.

Cardiopulmonary, metabolic, and perceptual responses during exercise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Multi-site Clinical Assessment of ME/CFS (MCAM) sub-study

“…Participants with ME/CFS rated exercise as requiring more effort throughout the test and these differences were maintained after matching for aerobic fitness. These results are consistent with a recent meta-analysis of 37 studies (involving 1016 with ME/CFS and 686 healthy controls) reporting large effect-size (d = 0.85) differences in RPE [65]. Based on the preponderance of data, it can be concluded that people with ME/CFS perceive exercise as requiring more effort than otherwise healthy people.…”

The maintained attention assessment in patients affected by Myalgic encephalomyelitis/chronic fatigue syndrome: a reliable biomarker?

“…In general people with CFS/ME perceive aerobic exercise as more effortful than healthy adults, this aspect is reflected in a meta-analysis but the exact causes are unclear [ 45 ]. The relevance of this effect requires further studies in order to elucidate the underlying mechanisms.…”

Pharmacological blockade of muscle afferents and perception of effort: a systematic review with meta-analysis

“…The perception of effort is involved in the regulation of human behavior [1] and influences how the nervous system selects a given movement amongst a myriad of possibilities [2, 3]. The perception of effort is altered in the presence of fatigue [4] and various pathologies such as chronic fatigue syndrome [5, 6], stroke [7] and cancer [8]. This perception is used to prescribe and monitor exercise in both rehabilitation programs [9, 10] and athletic training [11–13].…”