Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.

No abstract

Objective The aim of this pilot study was to assess physical fitness and its relationship with functional dyspnea in survivors of Covid-19, 6 months after their discharge from the hospital. Methods Data collected routinely from people referred for cardiopulmonary exercise testing (CPET) following hospitalization for Covid-19 were retrospectively analyzed. Persistent dyspnea was assessed using the modified Medical Research Council dyspnea (mMRC) scale. Results Twenty-three people with persistent symptoms were referred for CPET. Mean mMRC dyspnea score was 1 (SD = 1) and was significantly associated with VO2peak (%) (rho = −0.49). At 6 months, those hospitalized in the general ward had a slightly reduced VO2peak (87% [SD = 20]), whereas those who had been in the intensive care unit (ICU) had a moderately reduced VO2peak (77% [SD = 15]). Of note, the results of the CPET revealed that, in all patients, respiratory equivalents were high, power-to-weight ratios were low, and those who had been in the ICU had a relatively low ventilatory efficiency (mean VE/VCO2 slope = 34 [SD = 5]). Analysis of each individual showed that none had a breathing reserve <15% or 11 L/min, all had a normal exercise electrocardiogram, and 4 had a heart rate above 90%. Conclusion At 6 months, persistent dyspnea was associated with reduced physical fitness. This study offers initial insights into the mid-term physical fitness of people who required hospitalization for Covid-19. It also provides novel pathophysiological clues about the underlaying mechanism of the physical limitations associated with persistent dyspnea. Those with persistent dyspnea should be offered a tailored rehabilitation intervention, which should probably include muscle reconditioning, breathing retraining, and perhaps respiratory muscle training. Impact This study is the first to show that a persistent breathing disorder (in addition to muscle deconditioning) can explain persistent symptoms 6 months after hospitalization for Covid-19 infection and suggests that a specific rehabilitation intervention is warranted.