Objective:

To investigate the associations between three dimensions of fatigue (physical, cognitive, and emotional) and core physiological variables in post-COVID-19 patients.

Approach:

• Study Design: A longitudinal study involving 30 post-COVID-19 patients who reported fatigue levels via a mobile app and had physiological variables recorded using wearable sensors.
• Data Collection: Fatigue was reported four times daily, and physiological data (ECG, respiratory rate, blood oxygen saturation) were collected continuously during monitoring weeks.
• Statistical Analysis: Linear mixed models were used to assess associations between daily averages of fatigue dimensions and physiological variables, adjusted for confounders.

Key Findings:

• Interaction of multiple fatigue dimensions showed more consistent associations with physiological changes than single dimensions.
• Daily changes in fatigue correlated with fluctuations in resting heart rate, sample entropy of RR intervals, and LF peak frequency.
• Higher physical fatigue was associated with sympathetic dominance, while cognitive and emotional fatigue correlated with parasympathetic dominance.

Interpretation:

Limitations:

• Small sample size of 30 patients may limit generalizability.
• Exclusion of patients with comorbidities may affect the applicability of findings to broader populations.

Conclusion: