Caused by a new type of coronavirus, COVID-19 often targets the respiratory system and is associated with mild pulmonary symptoms (such as cough and dyspnea) but with pneumonia and hospitalization in the intensive care unit in severe cases. Sometimes, the disease symptoms are digestive disorders, lack of sense of smell and taste, lethargy, and premature fatigue. The early prevalence of this disease was reported as a severe acute respiratory syndrome (CoV-SARS) and Middle East respiratory syndrome (CoV-MERS) with severe lower respiratory tract infection in humans (
1). According to WHO, the latest confirmed COVID-19 cases were 260,079,122 persons, of whom 5,196,842 died. The COVID-19 incidence and mortality in Iran were 6,097,672 and 129,376, respectively (
2). Initially, the mortality rate of COVID-19 patients was reported to be 3 to 5%, but recent reports indicate an increase up to 9% (
3).
One of the most common problems in COVID-19 patients is fatigue and body aches (
4), defined as a nursing diagnosis, with a feeling of weakness and reduced capacity to perform mental and physical activities (
5). One study showed that two months after the incidence of COVID-19 in patients with a history of hospitalization, while none of them had a fever or signs of disease activity, half of them still complained of fatigue, and about 44% claimed the decreased quality of life (
6). Chronic viral infection in the lungs, brain, and other tissues may be one of the mechanisms associated with fatigue. This is due to the increase in the basal level of two molecules, interleukin-6 (IL-6) and interleukin-10 (IL-10), which cause inflammation in the body and are predictors of chronic fatigue (
7). An increase in these molecules is seen in patients with severe COVID-19 (
3). In addition to fatigue and body aches, the most common symptom seen in COVID-19 patients is dyspnea. The patient becomes prematurely tired as the disease progresses, even with simple life activities. Fatigued people do not have their previous energy. Thus, they do less activity and try harder to minimize activities of daily living, so this will affect their quality of life and self-confidence (
5). Woo showed that three indices of dyspnea, fatigue, and physical activity are interrelated, so higher fatigue and lower physical activity were reported in chronic obstructive pulmonary disease (COPD) patients (
8).
A review study by Soleimanifar and Hazrati showed that according to the 2020 physiotherapy guidelines for COVID-19 patients, cardiopulmonary physiotherapy is focused on the treatment and rehabilitation of acute and chronic respiratory conditions that can have an influential role in respiratory therapy and physical rehabilitation of the patients (
9-
12). Pulmonary rehabilitation uses a mixed multidimensional approach that includes training and breathing exercises to influence activity levels, symptoms, and complaints in patients with respiratory problems, intending to create maximum patient performance independence. One of the rehabilitation approaches is home-based rehabilitation, with the active involvement of the patient and his/her family in identifying needs and training (
13). Given that the focus of medical policies is currently on speeding up the patient's discharge from the hospital, reducing the stay length of the patient in medical centers and receiving care in the community and home-based health services as a care solution have received more attention, with features such as ease of access, low cost, client acceptance, and family involvement (
14).
A literature review shows that no study has yet addressed the impact of pulmonary rehabilitation intervention in patients with COVID-19 respiratory symptoms. However, two review studies on the effect of pulmonary rehabilitation and physiotherapy management of respiratory systems in COVID-19 patients concluded that physiotherapy could play an influential role in respiratory and physical rehabilitation of the patients, and pursed-lip breathing exercise, diaphragmatic breathing, local dilation of the lungs, and chest volume exercises were the most important ways to improve respiratory function of COPD patients including COVID-19 patients (
12,
15). Other researchers (Wang et al., Talman et al., Polastri et al., Demeco et al.) reviewed previous studies and recommended pulmonary rehabilitation as supportive care that could improve the respiratory function of patients with respiratory problems, especially patients with COVID-19 respiratory infection (
16-
19). Liu et al. also found that six-week respiratory rehabilitation was effective in respiratory function, lung capacity, and activities of daily living of older adults with COVID-19 (
20).
Given that COVID-19 is a newly emerged disease, there are a few scientific and documented findings on the effectiveness of rehabilitation interventions on fatigue, respiratory indicators, and activities of daily living of the patients. One of the most important organs involved in COVID-19 is the respiratory system. Moreover, fatigue and acute dyspnea adversely affect COVID-19 patients’ activities of daily living. Thus, these patients need long-term breathing exercises to speed up patient recovery after hospital discharge. Accordingly, raising COVID-19 patients' awareness of effective pulmonary rehabilitation techniques seems to be effective in reducing the patient's respiratory problems (cough ‚dyspnea‚ and fatigue) and improving the function of this vital system during hospitalization and home quarantine (
15).