Ab. No. 156 Exercise Intolerance in Individuals With Long Covid: A Cross-Sectional Analysis

Introduction:Long-COVID has emerged as a significant public health burden, affecting millions around the world. Exercise intolerance is a prominent symptom of Long-COVID and understanding its underlying mechanisms can help health professionals determine appropriate rehabilitation strategies. The aim is to determine potential causes of exercise intolerance in individuals with Long-COVID.Methods:Fifteen individuals (age=31±11years;87% female) with a confirmed COVID-19 diagnosis in the past and Post-Covid Functional Status ≥2 were included. Following ethical approval and informed consent, participants underwent a series of assessments including 6-min walk test, PFT, Echocardiography, Cardiopulmonary exercise testing (CPET) and Isometric peak torque (IPT). A symptom limited graded CPET was conducted on two consecutive days(Vyntus CPX System) on cycle ergometer using a standardized ramp protocol. IPT was determined using Humac Norm Isokinetic Device at 90º of knee flexion, with 10seconds hold for 3sets between 2-7days post CPET.Result:VO2peak was 20.6±4.8ml/kg/min (RER:1.2±0.1; peakHR:166±22; MVV%:62±10) and significantly lower than predicted values. IPT of dominant quadriceps was 113.4±44.6Nm. All participants terminated exercise due to lower extremity fatigue and inability to maintain peddling rate. Only seven (47%) participants exceeded 90%of their age-predicted MHR and only two crossed 70% of their predicted MVV; indicating possibility of peripheral contribution to exercise intolerance. This could be corroborated by significant moderate correlation between VO2peak and IPT (r=0.66, p=0.008).Conclusion:This sample of participants with Long-COVID had significantly lower VO2peak than predicted with a possible contribution from peripheral skeletal/neural processes that present as exercise intolerance.Implications:Peripheral causes of exercise intolerance also need to be considered while developing appropriate rehabilitation strategies.