Introduction: Post-COVID syndrome is characterized by the persistence of physical, mental or social symptoms beyond 12 weeks after a COVID-19 infection, without other defined causes.

Methods: A retrospective and descriptive study of patients with Post-COVID syndrome was conducted to describe the clinical and functional characteristics. Pulmonary function tests and the one-minute standing test (1STST) were performed to assess functional and respiratory capacity.

Results: 60% (n=60) were male and 40% (n=40) were female. The mean number of days after infection was 304.44 (95%CI,52-754). Mild COVID-19 occurred in 58%, 42% developed severe COVID-19 and 26% required ICU. 46% (n=46) had a reduction in 1STST and the Mann-Whitney test revealed no statistical difference between mild and severe patients. There is no correlation between 1STST reduction and asthma and/or COPD according to Spearman's correlation coefficient. In the respiratory function analysis we found: FEV1: 6% (n=6) reduced, RV: 11% (n=1) reduced, TLC: 10% (n=10) reduced, DLCO: 30% (n=30) reduced, MIP: 45% (n=45) reduced and MEP: 38% (n=38) reduced. There were significant differences for static volumes: RV, TLC, RV/TLC and DLCO between mild and severe patients, according to the Kruskal-Wallis test.

Conclusions: Impaired physical capacity affects both severe and mild COVID-19. The reduction in respiratory muscle pressures is prolonged for a long period of time after infection and affects both mild and severe patients. The damage caused to the lung parenchyma may result in a restrictive pattern that may persist for at least 10 months. Long-term monitoring of respiratory function is necessary to monitor the evolution of the restrictive pattern.