Effects of Exercise on COVID-19 Patients: A Narrative Review

Background: Challenges concerning patient management exist worldwide, particularly in the critical care. In this review, we have summarized some studies regarding respiratory physiotherapy and exercise in COVID-19 patients. Methods: For searching related articles, PubMed, Google Scholar, Embase, and the Web of Science databases were used. Keywords such as "respiratory physiotherapy" and "COVID-19," "exercise," "effect of exercise in COVID-19," and "respiratory physiotherapy for COVID-19 in ICU" were used to identify related papers until December 2021. The abstracts and entire texts were evaluated by 3 separate reviewers. Results: During the symptomatic phase, individuals may benefit from brief durations of bed rest. Exercise appears to provide both emotional and physical benefits for individuals in the early stages of infection. As a result, it may lower viral load, minimize cytokine storm, shorten the acute phase, and expedite recovery. Mild exercise may also increase the autophagy pathway, which improves the immune system function in response to COVID-19 infection. Keeping this in mind, intense activity, especially without the guidance of an expert physical therapist, is not advantageous during the inflammatory period and may even be regarded a second hit phenomenon. Mild exercises during bed rest (e.g., acute phase) may reduce the risk of pulmonary capillary coagulation and deep vein thrombosis. Conclusion: Although respiratory physiotherapy and prone positioning in hospitalized patients, particularly in critical care, can be challenging for medical staff, they are cost-effective and noninvasive approaches for COVID-19 patients. Early physiotherapy and muscle training exercise for patients in the intensive care unit (ICU) seems to be beneficial for patients and may reduce bed rest-induced weakness, improve oxygenation, and reduce length of stay. Finally, breathing exercises can improve some symptoms of COVID-19, like dyspnea and weakness.