Fatigue and Its Longitudinal Associations With Mood, Stress, Anxiety, and Hair Cortisol During the Lockdowns of the Coronavirus Disease 2019 Pandemic: A Cohort Study With Ecological Momentary Assessment

Objective: Fatigue is a debilitating symptom common to many disorders and diseases (including COVID-19) with chronic fatigue affecting an estimated 10.1% of adults. However, fatigue in the general population remains understudied, especially during periods of crisis or sustained societal stress. We aimed to identify psychological and biological factors of fatigue during the COVID-19 lockdowns in the general population and to examine whether early fatigue predicted later fatigue, stress, anxiety, and mood.

Methods: In this ecological momentary assessment study, 292 participants reported fatigue, stress, anxiety, and mood 5 times a day for two 7-day measurement periods (20,343 observations) during the 2 national lockdowns in Austria and Germany. Hair cortisol was obtained from 85 participants as a marker of long-term hypothalamic-pituitary-adrenal activity.

Results: Fatigue was associated with younger age ( b = -0.27, p <.001), higher perceived stress over the past month ( b = 0.50, p <.001), higher loneliness ( b = 0.29, p <.001), and lower income ( p <.001). Lower hair cortisol levels were related to a steeper diurnal increase in fatigue during the first lockdown ( p = .014). Finally, higher fatigue during the first lockdown was related to higher fatigue, higher stress, higher anxiety, and worse mood during the second lockdown (all p < .001).

Conclusions: Factors associated with high fatigue during the lockdowns of the COVID-19 pandemic were young age, low socioeconomic status, higher perceived stress over the past month, and higher loneliness. Results further suggest hypocortisolism in fatigued individuals during COVID-19. Early fatigue may signal psychological vulnerability during large-scale stressors.