Relationship between post-COVID-19 symptoms and daily physical activity.

The sample size was very small (n=18), limiting the statistical power and generalizability of the findings. The study used convenience sampling via social media, which may have introduced selection bias. Participants included both confirmed and suspected cases of prior SARS-CoV-2 infection, creating potential heterogeneity in the underlying condition. The study was observational and cannot determine causality; it is unclear whether low activity causes symptoms or symptoms cause low activity. ME/CFS was identified via self-report screening tools rather than clinical diagnosis, and post-exertional malaise was not assessed in detail. Medication use was not tracked, which could have influenced symptom reporting and activity levels. Data loss occurred due to technical difficulties with device synchronization for some participants.

The work was supported by the Manitoba Lung Association and the Physiotherapy Foundation of Canada. The funders had no direct involvement in the study design, data collection, or analysis.

Do not interpret the association between walking 5,000 steps and reduced next-day symptoms as evidence that increasing activity will safely treat post-COVID syndrome. This was a small observational study with a highly selected sample, and it did not test an intervention. In patients with post-exertional malaise, increasing activity without careful pacing can worsen symptoms.