Post-COVID-19 fatigue: A systematic review.

Abstract

Persistent fatigue following SARS-CoV-2 infection ranks among the most frequently reported long-term complaints. This systematic review searched PubMed, Web of Science, Cochrane Library, and PsycInfo, ultimately including 20 studies of moderate-to-high methodological quality encompassing 5,629 adult participants (aged 18–65). Identified risk factors included older age, female sex, severe acute-phase illness, a high comorbidity burden, and a prior diagnosis of depression or anxiety; an autoimmune etiology was also hypothesized. Various interventions were examined, mostly in small uncontrolled settings: a Chinese herbal formulation reduced breathlessness and fatigue; molecular hydrogen (H2) inhalation was associated with improvements in physical capacity (6-minute walk test) and respiratory function; hyperbaric oxygen and enhanced external counterpulsation also yielded fatigue relief; and an 8-week biweekly program combining aerobic exercise, strengthening, diaphragmatic breathing, and mindfulness improved muscle strength and physical function. The authors conclude that larger, well-controlled trials are needed to establish the efficacy of physical and psychological interventions for post-COVID-19 fatigue.

Mechanism

H2 inhalation is proposed to exert antioxidant and anti-inflammatory effects, potentially contributing to the observed improvements in physical capacity and respiratory function in post-COVID-19 patients.