The analysis of the 2017 Cochrane review reveals flaws, which means that contrary to its findings, there is no evidence that graded exercise therapy is effective. Because of the failure to report harms adequately in the trials covered by the review, it cannot be said that graded exercise therapy is safe. The analysis of the objective outcomes in the trials provides sufficient evidence to conclude that graded exercise therapy is an ineffective treatment for myalgic encephalomyelitis/chronic fatigue syndrome.

Conclusion The GET trials reviewed here are inherently biased: use of exercise may attract only the mildly affected and may deter the more disabled patients from participating. These trials go back for more than two decades, at the cost of considerable money and involving large numbers of patients. The flaws in the review and the trials, as discussed above, all created a bias in favour of the exercise intervention. Despite these flaws, they have found no significant evidence of objective improvement. The analysis of the objective outcomes in the trials provides sufficient evidence to conclude GET is an ineffective treatment for ME/CFS. Most studies failed to report on safety or adverse reactions, and White et al. (2011), one of the two studies that did, used an unrealistic definition. ME is characterised by an abnormally delayed muscle recovery after trivial exertion (Ramsay, 1988), commonly referred to as PEM. Exercise physiology studies reveal abnormalities in patients’ responses to exertion. Yet PEM is not a requirement for diagnosis according to the Oxford criteria, used by five of the studies, and only an optional criterion according to the Fukuda criteria, used by the other three studies in the review. If patients do not suffer from PEM, it is likely that they will have no problems exercising. This might be an important reason why outside of clinical trials things are different with many patients, who do suffer from PEM, reporting deterioration with GET. Given these considerations, one cannot conclude that GET is safe.

Acknowledgements The authors would like to thank M.V.’s parents for typing out his speech memos. The authors would also like to thank the reviewers for their help in improving the article.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article. Funding

The author(s) received no financial support for the research, authorship and/or publication of this article.