Repeated episodes of physical training induced hypoxia, may be associated with improved exercise tolerance in covid-19

Background: Repeated episodes of hypoxia by coronary artery ligation, precondition the myocardium to adapt against ischemic cardiac damage and arrhythmias. This case aims to highlight the role of hypoxia induced adaptation in exercise tolerance. Case and methods: A male physician aged 77 years, presented with COVID-19 on April 17, 2021. Acute phase COVID-19 pneumonia, and lung fibrosis were diagnosed by high resolution computerized tomography and chronic hypoxia, measured by oximeter (SpO2 saturation between 91%-93%). Regular physical training in the form of slow jogging, morning, and evening, was advised twice daily. Results: Treatment with physical training was associated with improved SpO2 saturation during exercise, from 83-84% to 89-91%. There was a significant increase in oxygen saturation during rest after treatment with physical training for two weeks. It is possible that repeated episodes of hypoxia during physical training, may have induced molecular adaptations in the heart and lungs, leading to increased exercise tolerance with increase in SpO2 saturation. Conclusions: Regular physical training in the form of jogging may be associated with improvement in exercise tolerance without causing hypoxia. There is no other study in humans, to our knowledge, that has examined the role of physical training induced hypoxia to achieve myocardial adaptations, characterized with improved SpO2 saturation.