Patients with COVID-19 have not only reduced respiratory capacity, but also diminished muscle strength, exercise capacity, weakness cardiac system. In parallel with aforementioned, physical activity level and quality of life get worse in this patients. Therefore, the patients with COVID-19 need exercise training after the discharged. In the literature, the achievement of exercise training in many aspects such as exercise capacity, lung health, respiratory muscle strength, dyspnea has been proven in many diseases such as chronic obstructive pulmonary disease and heart failure.~Effects of high-intensity interval aerobic exercise training on oxygen consumption, muscle oxygenation, physical activity level, pulmonary function, functional exercise capacity, respiratory and peripheral strength, inspiratory muscle endurance, functional status, dyspnea, fatigue perception and quality of life have not been investigated in literature in patients with COVID-19. According to inclusion and exclusion criteria, 15 patients for training group and 15 patients for control group will be included. All assessments will be completed in two days before and after eight weeks training.~Primary outcome measurement will be oxygen consumption (cardiopulmonary exercise test).~Secondary outcome will be muscle oxygenation (Moxy device), physical activity level (multi sensor activity device), pulmonary function (spirometer), functional exercise capacity (six-minute walk test), respiratory (mouth pressure device) and peripheral muscle (hand-held dynamometer) strength, inspiratory muscle endurance (incremental threshold loading test), functional status (Post-COVID-19 Functional Status Scale), dyspnea (London Chest Daily Living Activity Scale), fatigue (Fatigue Severity Scale) and quality of life (Saint George Respiratory Questionnaire).
Many structures and organs are adversely affected after COVID-19. The most obvious and common problem is lung involvement. In the pathology report of the patients, it has been shown that there are changes such as diffuse alveolar damage, bronchiolitis and interstitial fibrosis. The most prominent effect of COVID-19 in patients with reduced lung functions is reduced diffusion capacity. While the disease severity worsens, pulmonary fibrosis becomes more pronounced in cases. The complaints of dyspnea and fatigue of patients after discharged continue. Inspiratory and expiratory respiratory muscle weakness are observed in more than 50% of patients with COVID-19, measured in the first month after the discharged. This respiratory muscle weakness is associated with myopathy due to hypoxemia, oxygen support, prolonged bed rest and corticosteroid use, regardless of disease severity.~It is seen that these patients with COVID-19 need exercise training because of lung involvement, decreased exercise capacity and persistence of some symptom complaints after the discharged.