Exploring Physical Activity, Sleep, and Nutrition's Role in Fatigue Among Post-COVID-19 Patients

Background/Objectives: A significant number of patients experience prolonged symptoms following COVID-19 in particular cases of fatigue. Yet, pathomechanisms of COVID-19-related fatigue remain unclear. Methods: This study investigated patients after confirmed SARS-CoV-2 infection (PC) with relevant fatigue according to the Fatigue Assessment Scale (≥22 points) to rule out malnutrition as a driving factor for fatigue and to evaluate daily activity and sleep characteristics. Dietary behavior was recorded through food diaries and physical activity by self-reported (questionnaires) and objective (activity tracker) outcomes. Data were collected over a 7-day period and compared with a healthy control group (HC). A subgroup analysis of patients with fatigue and severe fatigue, as well as a sex-specific analysis, were included. Results: No significant differences in dietary intake were observed, but an indication toward a healthier Mediterranean diet in PC patients with a median Mediterranean Diet Score of 4 (IQR 3, 5) in HC vs. 5 (IQR 3, 6) in PC (p = 0.24). There were also no differences in physical activity, either by objective or subjective measures. However, the median sleep duration was 49 min longer in PC patients (p = 0.003). Conclusions: In conclusion, malnutrition did not significantly contribute to fatigue, yet patients with COVID-19-related fatigue showed increased sleep duration. As sleep characteristics play a crucial role in mental and physical wellbeing, the association of sleep, physical activity, and fatigue should be evaluated in further studies.