The study will include patients with the following respiratory system diseases: bronchial asthma, interstitial lung diseases (sarcoidosis, pulmonary fibrosis, etc.) and patients after lung transplantation enrolled in outpatient care by the attending physician.

All these patients must meet inclusion criteria, such as: stable disease status, no exacerbation within last 2 months. Patients with comorbidities (rheumatological, neurological, psychiatric, etc.) preventing them from being enrolled in a pulmonary rehabilitation program will be excluded from the study. All study participants will be divided into 3 groups according to their lung disease. Each group should contain 20 patients, who will be randomly split into an intervention and a control group of 10 patients each. The course of lung disease, its symptoms, medication, and the patient's functional status will be determined in detail. The following parameters will be objectively evaluated: lung function and respiratory muscle strength, exercise tolerance, chest expansion, dyspnoea, fatigue, anxiety and depression, quality of life in relation to lung disease and physical activity. The patients will be examined using spirometry, Modified Medical Research Council Dyspnea Scale, the Multidimensional Assessment of Fatigue Scale, self-report Beck Depression Inventory-II scale for adults and St. George's Respiratory Questionnaire examining the quality of life in relation to lung disease. Exercise tolerance testing will be performed through a 1-minute Sit-to-stand test. The level of physical activity will be examined using Axivity AX3 accelerometers, which the patient will wear for 7 days after the initial assessment, which will take place in one day. There will always be a long enough rest between examinations, so that fatigue cannot affect the course of the measurement. All assessments are non-invasive, and all the mentioned test methods are standardized and commonly used in patients with diseases of the respiratory system according to the recommendations of the Czech Pneumological and Phthisiological Society and the European Respiratory Society. All patients will be initially educated by a physiotherapist and instructed to independently perform the home exercise program including respiratory muscle training. This program will also include breathing exercises to correct the breathing pattern, exercises to strengthen the upper and lower limbs muscles, balance exercises and recommendations for endurance training. Respiratory muscle training will be performed using the Airofit PRO device. This breathing device can be set to a suitable resistance for both inhale and exhale to increase the strength of the inspiratory and expiratory muscles. Airofit PRO device can also be connected to an application in a smartphone, which records the ongoing results of the training as well as the frequency of the device use. This is a great starting point for its implementation within a telerehabilitation program, as well as for its self-directed use. The intervention group will perform the home exercise program independently with the use of an exercise brochure and at the same time with the support of telerehabilitation lessons with a physiotherapist twice a week via Zoom meeting. The control group will continue in a separate program according to the exercise brochure. To ensure a correct exercise performance all exercises in the exercise brochure will be individually practiced by a trained physiotherapist with each patient from both groups during the initial assessment. The assessment day will be divided into two parts:

1. all assessments in the morning; 2. exercise brochure introduction in the afternoon to avoid fatigue of patients. The final assessment will take place 6 weeks after the initial one. It will be exactly the same as the first one.