Cognitive Functions After COVID‐19 and Their Relationship With Disease Severity and Physical Fitness

Background The Coronavirus Disease 2019 (COVID‐19), which initiated a pandemic in 2020, continues to be prevalent. It may impact various organs and systems. Many COVID‐19 survivors experience cognitive symptoms, and their physical fitness may decrease postinfection. Objective To assess the impact of COVID‐19 and its severity on cognitive functions and to investigate the relationship between cognitive functions and physical fitness after COVID‐19. Methods This cross‐sectional study included individuals with a history of COVID‐19. The sociodemographic features of participants were recorded. The Montreal Cognitive Assessment (MoCA) was performed to evaluate cognitive functions. The 6‐min walk test and cardiopulmonary exercise test were performed to assess physical fitness. Results Fifty‐nine participants were evaluated at a median of 66 days after COVID‐19 diagnosis. Eighteen (30.5%) exhibited cognitive impairment. The participants with severe–critical COVID‐19 history had lower total MoCA (25 vs. 27, p = 0.009), language (4 vs. 6, p = 0.003), attention–concentration–working memory (5 vs. 6, p = 0.009), and executive functions scores (3.5 vs. 4, p = 0.035) than those with mild–moderate COVID‐19 history. In regression analyses, disease severity was related to lower total MoCA ( p < 0.001), language ( p < 0.001), and attention–concentration–working memory ( p < 0.001) scores. In regression analyses, shorter walking distance was related to lower executive functions score ( p = 0.001), and lower maximum oxygen consumption was related to lower short‐term memory score ( p < 0.001). Conclusion After COVID‐19, individuals may experience cognitive impairment. Cognitive impairment is more evident after more severe COVID‐19, especially in the areas of language and attention–concentration–working memory. There is an association between cognitive functions, particularly in short‐term memory and executive functions, and physical fitness following COVID‐19. Trial Registration: ClinicalTrials.gov: NCT04753346