Assessment of Exercise Capacity of Individuals with Long COVID: A Cross-sectional Study

Background: Clinical investigations of long-term effects of coronavirus disease 2019 (COVID-19) are rarely translated to objective findings.Objectives: To assess the functional capacity of individuals reported on deconditioning that hampered their return to their pre-COVID routine.Methods: Assessment included the 6-minute walk test (6MWT) and the 30-second sit-to-stand test (30-STST). We compared the expected and observed scores using the Wilcoxon signed-rank test. Predictors of test scores were identified using linear regression models.Results: We included 49 individuals, of whom 38 (77.6%) were recovering from mild COVID-19. Twenty-seven (55.1%) individuals had a 6MWT score lower than 80% of expected. The average 6MWT scores were 129.5 +/- 121.2 meters and 12.2 +/- 5.0 repeats lower than expected scores, respectively (P < 0.001 for both). The 6MWT score was 107.3 meters lower for individuals with severe COVID-19 (P = 0.013) and rose by 2.7 meters per each 1% increase in the diffusing capacity of carbon monoxide (P = 0.007). The 30-STST score was 3.0 repeats lower for individuals who reported moderate to severe myalgia (P = 0.038).Conclusions: Individuals with long COVID who report on deconditioning exhibit significantly decreased physical capacity, even following mild acute illness. Risk factors include severe COVID-19 and impaired diffusing capacity or myalgia during recovery.

Automated summary

This study assessed the functional capacity of individuals with long COVID and found that even mild cases resulted in decreased physical capacity. Severe cases and impaired diffusing capacity or myalgia during recovery were identified as risk factors.