St Clair Gibson, A, Grobler, L A, Collins, M et al. · Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine · 2006 · DOI
This study looked at athletes who reported unusual tiredness and couldn't train like they normally could, even though their bodies seemed to work normally during fitness tests. Researchers found that these athletes' muscles and heart/lung capacity were just as strong as athletes without fatigue problems, but they had higher scores for depression and mood problems. The study suggests that the excessive tiredness these athletes felt might be connected to depression rather than a physical problem with their muscles or fitness.
This study is relevant because it challenges assumptions that all persistent exercise-related fatigue must stem from measurable physical deficits, and explores the relationship between mood disorders and training intolerance. However, the ATI group explicitly did not meet ME/CFS diagnostic criteria, so findings may not directly apply to clinically-diagnosed ME/CFS patients, who often show objective post-exertional malaise distinct from depression.
This study does not prove that depression causes training intolerance, only that depression scores correlate with it in this particular group of athletes. The findings do not apply to ME/CFS patients, as the study specifically excluded those meeting chronic fatigue syndrome criteria. It also does not address post-exertional malaise (PEM), the hallmark symptom of ME/CFS that distinguishes it from simple overtraining or depression.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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