Assessing Air Travel Safety in Neuromuscular Dystrophy: Standard Versus Prolonged High Altitude Simulation Tests

Inclusion Criteria: * individuals with a confirmed diagnosis of NMD * age ≥ 5 years of age * absence of hypoxia at rest, defined as oxygen saturation ≥ 92% for two consecutive minutes while at rest and breathing room air * absence of daytime hypercapnea at rest, defined by partial pressure of carbon dioxide (pCO2) less than 45 mmHg on capillary or arterial blood gas at rest * patient or authorized substitute decision maker provides consent to study participation. Exclusion Criteria: * current respiratory tract infection * inability to comply with the study procedures * severe heart failure as defined by uncontrolled symptoms of heart failure, or left ventricular ejection fraction \< 30% * presence of a tracheostomy * use of domiciliary bilevel positive airway pressure (BPAP) for more than 12 hours daily * recent hospital admission within the past 4 weeks.