Objectives: The study aimed to evaluate the efficacy of telemonitoring symptoms, oxygen saturation (SpO2) and heart rate (HR) at rest and after submaximal exercise using a telemonitoring application for early detection of acute exacerbations (AEs) of fibrosing interstitial lung diseases (F-ILDs). Methods: The data collected included symptoms, SpO2, and HR at rest and after submaximal exercise, which were obtained through the use of an online telemonitoring application called Respiratory Disease Steward. The symptoms assessed included the intensity and frequency of cough, as measured by the Cough Assessment Test scale score, and breathlessness grade, as measured by the Modified Medical Research Council scale score. Physiological parameters, such as SpO2 and HR, were also measured at rest and after a 1-minute sit-to-stand test (1STST). Results: The data collected from 85 patients with stable F-ILDs included changes in symptoms, SpO2, and HR at rest and after 1STST over a minimum of six months. The telemonitoring application was found to have an average recording duration of 255.4±78.1 days, with 21 patients experiencing an AE. The increase in COAT?4 and mMRC?1, the decrease in SpO2 at rest?5% and SpO2 after 1STST ?4% had the highest value in predicting the occurrence of AEs in patients with F-ILDs 2 weeks in advance (AUC=0.854). Conclusions: An effective approach in telemonitoring applications would be the recording of cough and breathlessness, as well as SpO2 at rest and after 1STST. The use of a composite COAT and mMRC, along with a significant decrease in SpO2 at rest and after 1STST, could successfully aid in the early detection of AE in patients with F-ILDs.