Randomized Clinical Trial of the Comparison of Continuous Training vs. Interval Training as a Pulmonary Rehabilitation Program for Patients with Idiopathic Pulmonary Fibrosis (IPF): A Pilot Study

Background: This study aimed to compare the two methods of pulmonary rehabilitation including continuous and High-Intensity Interval Training (HIIT) on exercise capacity, and quality of life in inpatients with Interstitial Lung Disease (ILD). Methods: In this clinical trial, 30 patients diagnosed with IPF, were admitted to the pulmonary rehabilitation department and were randomly divided into two groups. In one group, the patients performed continuous training while walking on the treadmill with 60% of the maximum exercise capacity. In the other group, the patients performed HIIT with walking on a treadmill, including 2 min of activity with an intensity of 80% of the maximum exercise capacity, and 2 min of recovery with an intensity of 50 %. Results: The participants were all Idiopathic Pulmonary Fibrosis (IPF) with a mean age of 12.67±51.50. The mean variables of the six-Minute Walk Test (6MWT) distance, results of the sit-to-stand test, and quality of life (based on a 12-Item Short Form Survey) before and after rehabilitation were significantly different in intragroup analysis. The mean of oxygen saturation, dyspnea, and fatigue before and after rehabilitation in both groups had a significant difference (p<0.001). In the intergroup analysis, the 6MWT distance was significantly improved in favor of the continuous training group (p=0.02), and the quality of life was significantly improved in favor of the high-intensity interval training group (p=0.002). Conclusion: HIIT was associated with a significant improvement in exercise capacity and quality of life in ILD patients. However, there was no evidence that it was superior to continuous training.