Physical activity patterns among children and adolescents with mild-to-moderate chronic fatigue syndrome/myalgic encephalomyelitis.
Solomon-Moore, Emma, Jago, Russell, Beasant, Lucy et al. · BMJ paediatrics open · 2019 · DOI
Quick Summary
This study looked at how much physical activity children and teenagers with mild-to-moderate ME/CFS actually do each day using movement trackers. Most young people with ME/CFS were doing much less activity than health guidelines recommend, but the researchers found three different activity groups: some were more active, some did light activity, and some were mostly inactive. Interestingly, those doing some light activity felt they could function better and had less fatigue, though those doing more activity sometimes reported more anxiety.
Why It Matters
Many ME/CFS management approaches have traditionally recommended increasing activity, but this study provides real-world evidence that children with ME/CFS vary widely in their baseline activity patterns and may respond differently to activity changes. Understanding these distinct activity phenotypes helps clinicians recognize that one-size-fits-all activity recommendations may not be appropriate and that some young people with ME/CFS experience worsening anxiety with increased activity, suggesting the need for more personalized, cautious approaches.
Observed Findings
Only 3 participants (2.2%) met government physical activity recommendations of ≥1 hour daily, and 13 (9.4%) averaged 60 minutes per day.
Adolescents (≥12 years) were significantly less active than younger children, with no gender differences observed.
Three distinct physical activity classes emerged: 'active' (small proportion), 'light' (moderate activity), and 'inactive' (largest group).
'Light' activity class was associated with 10.35-point higher self-reported physical function and 1.60-point lower fatigue versus 'inactive' class.
'Active' class was associated with 13.79-point higher anxiety compared to 'inactive' class, despite greater physical function benefits.
Inferred Conclusions
Physical activity patterns vary considerably among children and adolescents with mild-to-moderate ME/CFS, warranting individualized rather than uniform treatment recommendations.
Some light activity may be beneficial for physical function and fatigue, but higher activity levels carry a risk of increased anxiety that warrants monitoring.
Paediatricians should assess individual activity patterns and tolerances before prescribing activity-based interventions.
Remaining Questions
What factors determine which children fall into 'active,' 'light,' or 'inactive' classes, and can these be predicted at diagnosis?
What This Study Does Not Prove
This cross-sectional study cannot prove that physical activity patterns cause differences in fatigue, function, or anxiety—only that they are associated. The study does not establish whether increased activity is safe or beneficial long-term for children with ME/CFS, and the finding that higher activity was associated with greater anxiety may reflect reverse causation (anxious patients self-limiting activity) rather than activity causing anxiety. The sample is limited to mild-to-moderate cases, so findings may not apply to severe ME/CFS.
Tags
Symptom:PainFatigue
Phenotype:Pediatric
Method Flag:Weak Case DefinitionNo ControlsExploratory Only
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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Do activity patterns reflect post-exertional malaise (PEM), or are other ME/CFS-specific mechanisms responsible for the anxiety observed in more active participants?
Would interventions gradually increasing activity from 'inactive' to 'light' levels be safe and sustainable, or do they risk triggering PEM?
How do activity patterns and their associations with symptoms evolve over time, and what are the long-term outcomes of different activity trajectories?