The patients who have agreed to participate in the study from patients diagnosed with idiopathic pulmonary fibrosis referred to the center of pulmonary rehabilitation from the interstitial lung disease polyclinic.

The healthy adults without additional disease

no intervention - cross-sectional observational only

The mouth pressure measurement was performed with the Micro-RPM® instrument from SensorMEDIC. Patient placed a rubber mouthpiece with flanges, on the device, sealed their lips firmly around the mouthpiece, exhaled/inhaled slowly and completely, and then tried to breath in as hard as possible. The patient was allowed to rest for about a minute and the maneuver was repeated five times. Verbal or visual feedback was provided after each maneuver. The aim is that the variability between measurements is less than 10 cm H2O. The maximum value was obtained.

The mouth pressure measurement was performed with the Micro-RPM® instrument from SensorMEDIC. Patient placed a rubber mouthpiece with flanges, on the device, sealed their lips firmly around the mouthpiece, exhaled/inhaled slowly and completely, and then tried to breath in as hard as possible. The patient was allowed to rest for about a minute and the maneuver was repeated five times. Verbal or visual feedback was provided after each maneuver. The aim is that the variability between measurements is less than 10 cm H2O. The maximum value was obtained.

The test was conducted in a 30-meter corridor in line with American Thoracic Society (ATS) guidelines. Patients were told that they should walk as fast as they can walk. Before and after the test, oxygen saturation, heart rate, Borg fatigue rating, and walking distance were recorded.

The International Physical Activity Questionnaire (IPAQ) was developed as an instrument for cross-national monitoring of physical activity and inactivity. This measure assesses the types of intensity of physical activity and sitting time that people do as part of their daily lives are considered to estimate total physical activity in MET-min/week and time spent sitting.

Dyspnea perceptions during daily life activities will assess according to the modified Medical Research Council (mMRC) scale. The mMRC Dyspnea Scale is best used to establish baseline functional impairment due to dyspnea attributable to respiratory disease; tracking the mMRC over time or with therapeutic interventions is of less certain clinical utility.The severity of dyspnea is rated on a scale of 0 to 4. "0" means no dyspnea perception, "4" means severe dyspnea perception.