Respiratory muscle strength and pulmonary function in unvaccinated athletes before and after COVID-19 infection: A prospective cohort study

Purpose: We investigated abnormalities and recovery in respiratory function after COVID-19 infection in an unvaccinated elite athlete population. Methods: Measurements included maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF). Results: The most frequent reported symptoms were fatigue with 80% and muscle/joint pain and headache with 50%, whereas only 10% reported dyspnoea and 30% cough. During follow-up, MIP was up to 13% and MEP up to 8% lower following COVID-19 infection. Likewise, FEV₁ was up to 2% and FVC up to 5% lower. While MEP and FEV₁ rapidly normalised, MIP and FVC still remained abnormal after 52 days of COVID-19 infection, thereby leading to a restrictive ventilatory pattern. PEF seemed unaffected during follow-up. Conclusions: COVID-19 decreases respiratory function in unvaccinated athletes despite reporting few respiratory symptoms and having mild disease. An initiative aimed at reducing the long-term adverse effects following COVID-19 infection seems warranted, which perhaps may be avoided through vaccination.