Introduction: Unexplained exertional dyspnea (UED) is common in non-severe covid survivors(NSCS) implied as deconditioning in most cases. Subclinical heart damage(SCHD), not detected by routine test, may underlie. Post exercise heart rate recovery time (HRRT) may be a marker. We aimed to compare cardiopulmonary exercise test (CPET) indices in 2 groups(Gp) of NSCS with deconditioning and different HRRT. Methods: In a cross sectional study, NSCS with UED underwent(CPET) 6 months after disease. Cardiopulmonary assays including chest image, pulmonary function test and echocardiography were normal. Patients with CPET diagnosis of deconditioning were selected. Upon HRRT, they were categorized into 2 Gp; normal(>20/min) and abnormal. VO2, AT, VE/VCO2, O2 pulse, were compared between 2 Gp. Results: 25 deconditioned NSCS were enrolled  (11  patients in Gp1 with abnormal HHRT?20  ,14 in Gp2 with HRRT >20 ). Mean HRRT was significantly greater than Gp1. Mean Vo2,AT, o2 pulse , ? Vo2/WR  were non-significantly greater in Gp2;while, Vd/Vt in rest and max load were greater in Gp1(details in table1).

Conclusion: On a small group of patients, our study supports the hypothesis that HRRT may indicate SCHD in NSCS; further studies with long term follow up and larger groups are needed.