Post-COVID Exercise Impairment Stems Mainly from Muscle Deconditioning
While healthcare has been rapidly building knowledge about COVID-19, data regarding post-COVID, long-term pulmonary sequelae is only beginning to trickle in.
A recent observational study out of Switzerland adds to a trend of data suggesting that muscle deconditioning, more than pulmonary limitations, serves as the driving force behind cases of reduced exercise tolerance lasting longer than three months.1 As you know, SARS-CoV-2 can cause severe pneumonia with dry cough, dyspnoea, hypoxemia, and diffuse ground-glass opacities on computed tomography.2
Reduced exercise capacity following a case of COVID-19 is common.3 In the current study, Kathleen Jahn and colleagues followed 44 of their patients discharged alive after severe pneumonia from COVID-19. At three months, all patients received cardio-pulmonary exercise testing (CPET). This consisted of various measurements of breathing and gases while using a cycle ergometer.
Their data is affected by the fact that all patients received both inpatient and outpatient physiotherapy. Here is what they found. Surprisingly, despite the severity of COVID - 19 pneumonitis, only 14% of survivors experienced pulmonary limitation after three months. While 100% patients received inpatient and outpatient physiotherapy, 23% were additionally sent to inpatient pulmonary rehab, and 9% were sent to outpatient pulmonary rehab. At three months, 54% demonstrated reduced exercise tolerance as indicated by impaired VO2max. VO2max serves as a strong predictor of future health, all-cause mortality, and cardiovascular risk.4
Among those with exercise impairment, the main limiting factor was deconditioning for 47%, cardiovascular for 26%, and pulmonary limitations for 26%. Among those with cardiovascular limitations, 60% had previous cardiovascular disease.
The current study adds to the data of two other studies finding muscle deconditioning to be the primary cause of prolonged exercise intolerance after COVID-19.5,6 The authors of the current study state that the prevalence of physical deconditioning underscores the importance of physiotherapy for COVID-19 survivors. At Advanced Physiotherapy, patients can receive supervised and/or independent programs to restore conditioning following an injury or illness. These programs are complimented by access to Advanced’s patient-only gym.