LaManca, J J, Sisto, S A, DeLuca, J et al. · The American journal of medicine · 1998 · DOI
This study looked at how exercise affects thinking and mental processing in people with ME/CFS compared to healthy people. Both groups did exhausting exercise on a treadmill, then took thinking tests right after and 24 hours later. People with ME/CFS performed worse on these thinking tests after exercise, particularly on tasks involving speed and attention, and their thinking stayed impaired the next day.
This research provides objective evidence that ME/CFS patients experience not just physical exhaustion after exertion, but measurable cognitive decline—a phenomenon called post-exertional malaise (PEM). Understanding that cognitive function is affected by exercise, similar to physical symptoms, validates patient experiences and suggests cognitive testing could be useful in evaluating post-exertional deterioration.
This study cannot establish whether cognitive impairment is caused by exercise-induced physiological changes, deconditioning, motivation, or other factors. The cross-sectional design and single exhaustive exercise bout do not establish whether this pattern occurs with all types of activity or only maximal exertion. It also does not clarify the mechanisms underlying the cognitive decline or whether it represents permanent damage or temporary dysfunction.
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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