Cardiopulmonary function alterations in mild and moderate SARS-CoV-2 patients: a longitudinal comparison of pre-infection and early recovery phases

The purpose of this study is to compare and analyze the changes of CPET and pulmonary function indexes in patients with mild and moderate SARS-CoV-2 before infection and in the early recovery period, and to explore the influence of SARS-CoV-2 on cardiopulmonary fitness and its pathogenesis. Clinical data of 39 cases are collected, and paired analyses of CPET and pulmonary ventilation parameters before and after infection are performed using software SPSS. Bivariate correlations are analyzed for days post-infection, VO_2peak decline rate, VO_2peak/kg after infection, AHRR decline rate, and residual symptom count. The results show that VO_2peak, VO_2peak/kg, and AT significantly decreased after infection. The VE/VCO₂ slope increased, while PetCO₂, VE_peak, and VE/VCO₂ minimum showed reductions. FVC, FEV1, and FEV1/FVC remained unchanged. OUES significantly declined, along with AHRR and HR_peak, although no significant differences are observed in HR_rest, HRR-1 min, and HRR-2 min. The number of residual symptoms is significantly correlated with VO_2peak/kg and its decline rate, but not with infection duration. Additionally, the decline rate of VO_2peak/kg is strongly associated with post-infection time and post-infection VO_2peak/kg. VO₂/HR and power also decreased significantly. Moreover, after SARS-CoV-2 infection, cardiopulmonary function, including cardiac chronotropic and muscle function, is significantly impaired in mild and moderate patients. Residual symptoms are closely linked to cardiopulmonary function. Given the large proportion of mild and moderate cases, these findings offer valuable insights for developing targeted interventions to prevent further symptom progression and improve cardiopulmonary health in this population.