Exploring the Impact of Fatigue on Exercise Tolerance in Post-COVID Individuals

Abstract

<b>Introduction:</b> After acute COVID infection, individuals experience fatigue and a reduced exercise tolerance, however the relationship between these variables has not been established. <b>Aim:</b> This study explored the impact of fatigue severity on exercise tolerance in individuals post-COVID infection. <b>Methods:</b> This observational cohort analysis of individuals attending COVID-rehabilitation was assessed using the Functional Assessment of Chronic Illness Therapy – Fatigue (FACIT-F) questionnaire and Incremental Shuttle Walk Test (ISWT) pre- to post- rehabilitation. Individuals were split into mild and severe fatigue (FACIT-F&lt;/≥30) groups. <b>Results:</b> 295 individuals were assessed (64% male, mean[SD] age 54[15] years, BMI 30.1[8.7] kg/m²). 193 (65%) individuals were in the severe fatigue group. Baseline ISWT distance was reduced in the severe fatigue group (287[181]m) compared to the mild fatigue group (396[217]m, p&lt;0.05). There was a weak positive correlation between Pre-FACIT-F and baseline ISWT (r=0.28). There was a significant improvement in ISWT following rehabilitation of 90[114]m and 62[77]m for severe and mild fatigue groups respectively but there was no differences between groups (p=0.13) <b>Conclusion:</b> Those with severe fatigue had reduced exercise tolerance compared to those with mild fatigue prior to rehabilitation. Rehabilitation improves exercise tolerance in those with mild and severe fatigue, and there are no differences between groups.