I am currently in the process of writing this meta-analysis. I originally planned on posting all of the sections in one long post. The length of the sections that I have completed so far exceed the length that many CFS patients can read hence I will post this meta-analysis in parts. As I complete each part, I will post it. After I have completed all parts, I will combine them and post the meta-analysis in its entirety.
Graded exercise therapy (GET) is physical activity that starts slowly and gradually increases over time (1). GET is often recommended as a treatment for Chronic Fatigue Syndrome (CFS.) This meta-analysis will examine the theoretical basis for recommending GET for CFS. This article will also scrutinize the studies contained within the scientific literature on GET and CFS. Following this, the physiological effects that GET may have on CFS will be examined.
The Theory Behind Recommending GET for CFS
The psychosocial model for CFS is the underlying theory for recommending GET for CFS (2). This model proposes that the CFS patient can recover by modifying beliefs, behaviour and addressing deconditioning. GET and Cognitive Behaviour Therapy (CBT) are often recommended as tandem treatments under the psychosocial model of CFS. This meta-analysis will primarily analyse GET for CFS, not CBT, although both of these treatments share many commonalities including arising from the same theory that underlies the psychosocial model for CFS (2). Despite the aforementioned inextricable link between GET and CBT, it is often theorised that GET will specifically benefit CFS patients by creating a reversal of the deconditioning process (2). There exist nuanced variations of the psychosocial model for CFS however they all share the common premise that GET should be used as a primary treatment to halt and then reverse the deconditioning process in CFS.
Fulcher et al. typify a large portion of the psychosocial school by supporting the notion that the physical weakness accompanying CFS is directly caused by physical deconditioning, as a consequence of inactivity. Fulcher et al. cite the improvement in well-being scores correlating with an increase in strength and exercise capacity from GET. Fulcher et al hypothesise that the disability that accompanies CFS is a consequence of both physical deconditioning and a low threshold for specific somatic perceptions (3).
Kinesiophobia (the fear of movement) has been linked with CFS patients (4) (5) (6). Several studies have suggested that the avoiding of physical activity may cause a greater burden for CFS patients (7) (8) (9). These studies hypothesis that by CFS patients avoiding physical activity, it causes them to engage in maladaptive behaviour that may perpetuate their illness. These studies continue on to state that this is part of the rationale for GET as a treatment of CFS.
There exist two competing hypothesis advocating the use of GET for CFS. The first hypothesis proposes that the pathophysiology of CFS is mainly irreversible however GET can lead to an improvement in the quality of life for the CFS patient (10). The second hypothesis suggests that the pathophysiology of CFS is entirely reversible and that the treatments of GET and CBT can potentially cure CFS (10).
Criticisms of the Theory Behind Recommending GET for CFS
The theory that the deconditioning that accompanies CFS is an etiological factor causing disability or indeed CFS itself is a position that contrasts many studies. Friedberg et al. and Lapp et al. have found that patients with CFS are already functioning at their maximum ability in regards to energy (11) (12). This suggests that although disability in CFS correlates with degree of physical functioning, it does not cause an impaired degree of functioning. Therefore a more likely scenario than the “deconditioned theory” is that CFS patients have a low degree of physical activity due to the nature of having a debilitating, chronic and physiological illness. The “deconditioning theory” is also problematic due to several studies finding that physical and mental exertion by CFS patients cause an impermanent yet significant decline in functioning (13) (14) (15). If deconditioning was an etiological factor in CFS, it would be expected that exertion would cause an improvement in functioning ability, not decline.
Lane et al. conducted a study that concluded that CFS patients have an impaired muscle energy metabolism which cannot be explained by physical inactivity or a psychiatric disorder (16). The Lane et al study claims that the heart rate response to exercise by CFS patients suggests that CFS patients were no more deconditioned that those with a normal lactate response (16). A study was performed by Bazelmans et al. examining various physical conditioning biomarkers in CFS patients and controls, before and after exertion. This study concluded that physical deconditioning is not a perpetuating factor in CFS (17).
Sampson et al. (23) found that the amount of bed rest CFS patients indulge in at illness onset was not predictive of having a fatigue syndrome 6 months later. The authors’ concluded that CFS has no relationship to over-resting or deconditioning but rather a yet to be identified physical abnormality. Sampson et al. are critical of studies that link CFS to deconditioning as these studies have no data regarding the original fitness of the CFS patient, prior to illness. Sampson et al. conclude that deconditioning is a result of the chronic illness, CFS, this is as opposed to the chronic illness that is CFS being perpetrated by deconditioning. Sampson et al. found no relationship between fitness and bed rest at CFS onset.
The countless anecdotal reports of athletes contracting CFS (as opposed to athletic burnout) is in itself proof to nullify the argument that deconditioning is a necessary condition accompanying CFS. Many athletes, in their prime, have been diagnosed with CFS. If deconditioning played a major role in the pathophysiology of CFS, athletes would be immune from CFS. The medical literature suggests that athletes are often CFS patients hence the psychosocial model that definitively states that CFS disability is always caused by physical deconditioning is flawed.
The theory that kinesiophobia (the fear of movement), plays an integral part in the pathophysiology of CFS is a viewpoint that contradicts many studies. Nijs et al. performed a study on exercise in CFS patients with widespread muscle or joint pain. The study authors’ concluded that there is no correlation between kinesiophobia and exercise capacity or activity limitations in CFS patients (18). A study by Gallagher et al. concluded that patients with CFS (and without a co-morbid psychiatric disorder) do not have an exercise phobia (19). These studies support the notion that CFS patients do not have kinesiophobia but rather are cautious about overexertion as this may have debilitating physiological consequences on their illness.
One of the leading proponents of the psychosocial model of CFS, Professor Wessely, found that CFS patients don’t have negative attitudes towards psychiatry. The Wessely and Woods study compared various mental attitudes of CFS patients with rheumatoid arthritis patients. The authors found no difference between both groups of patients in regard to perfectionism, attitudes towards mental illness, defensiveness, social desirability or sensitivity to punishment (20). This study result suggests that psychological factors don’t play a significant role in CFS, when it is compared to other chronic illnesses. Le Bon et al found that personality structure doesn’t play a major role in CFS (21). Vollmer-Conna et al concluded that psychosocial factors including psychiatric history, mood, coping style and personality have no major effect on CFS patients’ illness outcomes (21). These study results suggest that maladaptive behaviour is not prevalent among CFS patients. Maladaptive behaviour was proposed as the mechanism behind the supposed kinesiophobia among CFS patients.
Part 2 of this meta-analysis can be found here: https://livingwithchronicfatiguesyndrome.wordpress.com/2010/09/10/a-meta-analysis-of-the-efficacy-of-graded-exercise-therapy-in-treating-cfs-part-2/
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- Sampson et al. Close analysis of a large published cohort trial into fatigue syndromes and mood disorders that occur after documented viral infection. http://iacfsme.org/BULLETINSUMMER2010/Summer2010SampsonAnalysisCohortTrial4481/tabid/435/Default.aspx