Deconditioning

Deconditioning is the decline in physical function of the body as a result of physical inactivity and disuse. The most important feature of deconditioning is a decline in muscle strength and bulk. It is usually reversible. It is often seen in the elderly and the infirm due to bed rest and inactivity. Risk factors include illness, disability, chronic disease, medical and psychosocial circumstances.

The deconditioning hypothesis proposed by proponents of the biopsychosocial model (BPS) of chronic fatigue syndrome (CFS) claims that the muscle fatigability, chronic fatigue, different types of pain, post-exertional malaise and all other symptoms experienced in ME/CFS, are the result of deconditioning, combined with inappropriate behavioral responses to symptoms. The theory proposes that patient's claims of their inability to exercise or exert themselves is actually due to a "fear of exercise" rather than rooted in reality. It is consequently proposed that psychological interventions such as cognitive behavioral therapy (CBT) should be employed to help the patient overcome their "unhelpful beliefs", while physical programs such as graded exercise therapy (GET) or exercise are employed to help the patient recondition their body.

The deconditioning theory has been used as justification treating ME/CFS with graded exercise therapy to improve fitness, and with cognitive behavioral therapy to address supposed inappropriate fear of exercise.

The deconditioning hypothesis has been largely abandoned due to significant evidence disproving it, combined with high rates of harm and lack of effectiveness of the treatments. Significant abnormal findings in ME/CFS have proved that there is an ongoing disease process rather than simply "symptoms without disease", and cannot explain the degree of orthostatic intolerance found in patients.

Evidence
In 2005 Peter White, an influential proponent of the deconditioning hypothesis since the 1990s, stated that: "We do not know whether this deconditioning maintains the illness or is a consequence."

Despite the lack of evidence for the deconditioning hypothesis, White and other members of the Wessely school promoted this belief and developed treatments based on it, which were adopted in a number of countries including the United States, United Kingdom, and Netherlands. In their literature review, Clark and White (2005) found that people with chronic fatigue syndrome were at least as deconditioned as healthy controls with a similar level of physical inactivity, but did not draw conclusions about whether they were more deconditioned. Clarke and White later became authors of the highly controversial PACE trial.

Results from two-day cardiopulmonary exercise tests provide clear evidence that patients with ME/CFS have an abnormal response to exercise, which is not the result of deconditioning. A large Dutch study by van Campen et al. (2018) found that deconditioning could not explain the cardiac index and stroke volume index changes in patients with ME/CFS that occurred during a normal tilt test.<ref name=":

Nakatomi and colleagues (2014) found widespread evidence of neuroinflammation in patients with ME/CFS, and that neuroinflammation was correlated with the severity of neuropsychologic symptoms, while a review by Nijs and colleagues (2014) found evidence of an altered immune response to exercise in patients with ME/CFS.

Notable studies
- (Full text)
 * 1992, Skeletal muscle metabolism in the chronic fatigue syndrome. In vivo assessment by 31P nuclear magnetic resonance spectroscopy
 * 2001 - Is physical deconditioning a perpetuating factor in chronic fatigue syndrome? A controlled study on maximal exercise performance and relations with fatigue, impairment and physical activity?
 * 2010 - Postexertional Malaise in Women with Chronic Fatigue Syndrome
 * 2011 - Tired of being inactive: a systematic literature review of physical activity, physiological exercise capacity and muscle strength in patients with chronic fatigue syndrome
 * 2014, Altered immune response to exercise in patients with chronic fatigue syndrome/myalgic encephalomyelitis: A systematic literature review (Full text)
 * 2014, Neuroinflammation in Patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: An 11C-(R)-PK11195 PET Study
 * 2016 - Unexplained exertional dyspnea caused by low ventricular filling pressures: results from clinical invasive cardiopulmonary exercise testing


 * Cort Johnson breaks down the study in Health Rising article The Exercise Intolerance in POTS, ME/CFS and Fibromyalgia Explained? Article Heading: "Not Deconditioning"
 * "The study also indicated neither deconditioning or a reduced maximal effort, both of which have been suspected in ME/CFS, play a role in the exercise intolerance found. In fact, deconditioned people, ironically, exhibit an opposite finding (increased as opposed to decreased filling pressures) to that found in this study."


 * 2018 - The Abnormal Cardiac Index and Stroke Volume Index Changes During a Normal Tilt Table Test in ME/CFS Patients Compared to Healthy Volunteers, are Not Related to Deconditioning
 * 2021, Deconditioning does not explain orthostatic intolerance in ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome) - (Full text)

Learn more

 * Tired of being inactive: a systematic literature review of physical activity, physiological exercise capacity and muscle strength in patients with chronic fatigue syndrome