Effects of short-term breathing exercises on respiratory recovery in patients with COVID-19: a quasi-experimental study

Background: Coronavirus disease 2019 (COVID-19) is a highly infectious respiratory tract disease. The most common clinical manifestation of severe COVID-19 is acute respiratory failure. Respiratory rehabilitation can be a crucial part of treatment, but data lack for patients with COVID-19. This study investigates the effects of short-term respiratory rehabilitation (i.e., breathing exercises) on respiratory recovery among non-ICU hospitalized patients with COVID-19. Methods: This was a quasi-experimental, pre-and post-test study. The study recruited 173 patients hospitalized with moderate to severe COVID-19. All the patients received standardized care for COVID-19, and 94 patients in the intervention group also received the intervention of breathing exercises, which included breathing control, followed by diaphragmatic breathing, deep breathing, or thoracic expansion exercise, and huffing (forced expiratory technique) and coughing. Data on the mean values of peripheral oxygen saturation (SpO2) need for oxygen therapy (liter/min), respiratory rate (breaths/minute), and heart rate (beats/minute) were collected at baseline, 4 days, and 7 days after the baseline assessment. Analysis of variance on repeated measures was applied to compare the mean value of outcome measures of all the time points. Results: The mean (±SD) age of the intervention (69.6% men) and control group (62.1% men) were 50.1 (10.5) and 51.5 (10.4) years, respectively. At 4-day of follow-up, SpO2 (96.6% ±1.9 vs. 90.7% ±1.8, P<0.001), need for oxygen therapy (0.8 ±2.6 vs. 2.3 ±2.9, P<0.001), respiratory rate (20.5 ±2.3 vs. 22.3 ±2.5, P<0.001), and heart rate (81.2 ±9.5 vs. 89.2 ±8.9, P<0.001) improved in the intervention group compared to the control group. At 7-day follow-up, differences remained significant concerning the oxygen saturation and the need for oxygen therapy (P < 0.001) between the groups. Conclusions: Our results indicate that breathing exercise, even for a short period