The evidence base for physiotherapy in myalgic encephalomyelitis/chronic fatigue syndrome when considering post-exertional malaise: a systematic review and narrative synthesis, by Marjon E A Wormgoor & Sanne C Rodenburg in Journal of Translational Medicine vol 19, Article no: 1 (2021)
Due to the inconsistent use of diagnostic criteria in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), it is unsure whether physiotherapeutic management regarded effective in ME/CFS is appropriate for patients diagnosed with criteria that consider post-exertional malaise (PEM) as a hallmark feature.
To appraise current evidence of the effects of physiotherapy on symptoms and functioning in ME/CFS patients in view of the significance of PEM in the applied diagnostic criteria for inclusion.
A systematic review of randomized controlled trials published over the last two decades was conducted. Studies evaluating physiotherapeutic interventions for adult ME/CFS patients were included. The diagnostic criteria sets were classified into three groups according to the extent to which the importance of PEM was emphasized: chronic fatigue (CF; PEM not mentioned as a criterion), CFS (PEM included as an optional or minor criterion) or ME (PEM is a required symptom). The main results of included studies were synthesized in relation to the classification of the applied diagnostic criteria. In addition, special attention was given to the tolerability of the interventions.
Eighteen RCTs were included in the systematic review: three RCTs with CF patients, 14 RCTs with CFS patients and one RCT covering ME patients with PEM. Intervention effects, if any, seemed to disappear with more narrow case definitions, increasing objectivity of the outcome measures and longer follow-up.
Currently, there is no scientific evidence when it comes to effective physiotherapy for ME patients. Applying treatment that seems effective for CF or CFS patients may have adverse consequences for ME patients and should be avoided.
The therapeutic applications evaluated in this review and considered relevant for physiotherapy consisted of one or more of the following elements: physical activity, body awareness, health education or orthostatic training.
The main physical activity interventions were GET and activity pacing (AP). GET is based on the notion that the fatigue is maintained by deconditioning and avoidance of activity. Accordingly, it is assumed that one can overcome the fatigue by increasing the activity level and physical fitness by means of low-level aerobic exercise with a rigid gradual increase of intensity and amount. In some studies, heart rate monitors were used during exercise sessions to help participants meet the prescribed intensity levels [58, 61, 73, 74]. GET was given alone [58, 74] or as part of a rehabilitation program [59, 68, 76].
AP is a strategy aimed at reducing the frequency and severity of PEM by focusing on awareness and knowledge of one’s limits and early signs of exacerbation. It targets on prioritizing of activities, being as active as possible within one’s limits, and alternating active and rest periods . In some programs focusing on AP [67, 75], the principles of the Energy Envelope Theory  were applied. According to this theory, ME/CFS patients should not expend more energy than they perceive they have (energy-envelope), as this results in PEM and increased disability. In another program , adapted pacing therapy (APT) was applied to encourage participants to restrict their activity levels to below 70% of their perceived limits. AP was given alone as a therapy , as part of GET with pacing , as graded exercise self-help (GES) guided by symptoms , as part of a rehabilitation , educational  or self-help program [63, 64, 67], or as a comparison intervention .
Body awareness incorporates coordinated body posture and movement, breathing, and meditation techniques. Two original eastern approaches of exercise and healing techniques, Qigong [69,70,71] and isometric yoga , were evaluated. In addition, body awareness therapy was included in a rehabilitation program . Several health education programs with different objectives were included. They aimed at encouraging GET  or AP , focused on pain physiology  with the intention to alter pain cognitions and thereby reduce catastrophizing and kinesiophobia, or provided self-management education aimed at accepting and improving ability to cope with ME . In one study, orthostatic (tilt) training was used to reduce orthostatic intolerance .
The control interventions consisted of care as usual [58,59,60, 63, 67, 74], waitlist for intervention [69,70,71,72], relaxation therapy [61, 64, 73], exercise [65, 68], CBT [58, 76], sham-training  or supportive listening . One of the RCTs included CBT  and one supportive listening  as additional experimental arms; these were considered as control interventions in this review.
The median treatment duration was 12 weeks. It was not always clear by whom the intervention was delivered, but all interventions were considered relevant for physiotherapy despite the fact that some were led in cooperation with or by peers [67, 75], a nurse , an occupational therapist [58, 64, 67], a clinician therapist , an exercise physiologist [58, 73], a yoga instructor , a qigong master [69,70,71] or an interdisciplinary team [66, 68].