E2 ModeratePreliminaryPEM ?LongitudinalPeer-reviewedMachine draft
Relationship between post-COVID-19 symptoms and daily physical activity.
Sarmento, Antonio, Webber, Sandra, Sargent, Shelley et al. · Frontiers in rehabilitation sciences · 2025 · DOI
Quick Summary
This study tracked 18 people with post-COVID symptoms (11 of whom also had ME/CFS-like symptoms) for a week using smartwatches and daily surveys to see how their symptoms related to how much they walked each day. The researchers found that dizziness had the strongest connection to reduced activity—people with more dizziness walked fewer steps both on the same day and the next day. They also discovered that when people had lower fatigue or chest pain the previous day, they were more likely to walk 5,000 or more steps the next day.
Why It Matters
Many people with ME/CFS experience post-COVID-like symptoms and struggle with conventional exercise advice because physical activity can worsen their condition—a phenomenon called post-exertional malaise. This study helps clarify which specific symptoms most strongly predict reduced activity levels, providing evidence to guide more personalized, symptom-informed rehabilitation approaches rather than one-size-fits-all exercise prescriptions. The use of wearable technology also demonstrates a practical method for monitoring this vulnerable population over extended periods.
Observed Findings
- Participants with ME/CFS symptoms (n=11) reported significantly more severe PCS symptoms and lower functional capacity than those without ME/CFS symptoms.
- Daily average step count was 4,067 steps (range 3,638-4,497) over 117 days of valid data.
- Greater dizziness was associated with fewer steps on the same day (OR 0.94, p=0.026) and following day (OR 0.91, p=0.016), independent of ME/CFS symptom status.
- Lower fatigue levels were associated with achieving ≥5,000 steps the previous day (OR 0.69, p=0.043).
- Lower chest pain was associated with walking ≥5,000 steps the previous day (OR 0.76, p=0.048).
Inferred Conclusions
- Dizziness is the symptom most consistently linked to reduced physical activity in PCS patients, affecting activity on both current and subsequent days.
- Fatigue and chest pain have a more complex relationship with activity—lower levels preceding a day are associated with higher activity the next day, suggesting possible symptom improvement with minor activity or activity limitation preventing symptom worsening.
- The relationship between symptoms and activity in PCS appears relatively consistent whether or not ME/CFS-like symptoms are present, though patients with ME/CFS symptoms report worse overall severity.
- Wearable devices combined with daily symptom tracking provide valuable real-world data for understanding individual activity-symptom patterns in PCS management.
What This Study Does Not Prove
This study cannot establish causation or determine whether symptoms caused reduced activity, activity worsened symptoms, or both occurred due to a third factor. The very small sample size (n=18) and predominance of female participants limits generalizability to broader PCS and ME/CFS populations. The study also does not test specific interventions or prove that symptom-adjusted activity recommendations would actually improve outcomes.
Tags
Symptom:Post-Exertional MalaiseFatigue
Phenotype:Long COVID Overlap
Method Flag:Small SampleExploratory OnlyMixed Cohort