Chronic respiratory diseases, such as Chronic Obstructive Pulmonary Disease (COPD), are a leading cause of death globally. These diseases not only contribute significantly to mortality but also lead to a decline in physical capacity, limiting daily activities and perpetuating a vicious cycle of deconditioning. Dyspnea (shortness of breath) is a major symptom, seen in 56 to 98% of COPD patients, and is linked to decreased exercise tolerance and muscle dysfunction. It often leads to reduced physical activity, further worsening respiratory function and quality of life. Dyspnea severity is associated with increased mortality, hospitalizations, and anxiety. The main therapeutic approach for these patients is pulmonary rehabilitation, which improves exercise tolerance, quality of life, and reduces hospitalizations and exacerbations. However, dyspnea limits exercise and is often a barrier to continued physical activity.

Virtual reality (VR) technology has shown promise in managing symptoms like pain, anxiety, and dyspnea by providing a distraction. Studies suggest that VR can improve dyspnea and anxiety, particularly in patients hospitalized for conditions like COVID-19. However, research on VR's immediate effects on exercise capacity is limited, with most studies focusing on non-immersive exergames rather than immersive VR. The potential of VR to improve exercise tolerance in patients with chronic respiratory diseases remains uncertain. Our study aims to test this hypothesis through a randomized crossover trial to assess VR's impact on dyspnea and exercise tolerance in these patients.

Inclusion Criteria:

• Patient aged 18 years or older
• Patient with a chronic respiratory disease requiring pulmonary rehabilitation
• Patient with dyspnea assessed as mMRC ≥ 0 (Annex 3)
• Patient undergoing pulmonary rehabilitation at the Paris Saint-Joseph Hospital
• Patient affiliated with a health insurance plan
• French-speaking patient
• Patient who has provided informed, explicit, and voluntary oral consent

Exclusion Criteria:

• Contraindications for an endurance reconditioning program (neurodegenerative diseases, severe neurological deficits, unstable cardiovascular diseases)
• History of motion sickness, vertigo, vestibular impairment, labyrinthitis
• History of seizures or other neurological or psychiatric comorbidities
• Severe visual impairments
• Patient already included in a Type 1 interventional research protocol (RIPH1)
• Patient under guardianship or curatorship
• Patient deprived of liberty
• Patient under legal protection
• Pregnant or breastfeeding patient