Effect of Intermittent Hypoxia on Ventilatory Endurance in Healthy Volunteers

Sleep apnoea syndrome is a common disorder responsible for poor sleep quality and repeated oxygen depletion in the blood. Patients suffering from this disease experience a reduction in their endurance, i.e. their ability to make prolonged efforts. This loss of muscular endurance affects breathing in particular. It is known that poor sleep reduces endurance, but it is not knwon whether the repeated lack of oxygen for several hours at night also has this effect. This information could help improve the management of certain acute respiratory illnesses (asthma attacks, respiratory infections, etc.). This project therefore seeks to establish a link between repeated oxygen deprivation and a reduction in the human brain's ability to train respiratory muscles. To this end, the healthy volunteers in this study will perform the same breathing exercise (breathing for as long as possible through a mask that makes inspiration difficult) twice: once after 6 hours' exposure to repeated oxygen deprivation, and once under conditions of normal oxygenation. The order of these exercises will be randomized. These exercises will take place in a special room, a hypoxia chamber, where it is possible to deplete the air breathed in oxygen.

Inclusion Criteria: * Non-excessive coffee drinker (\< 3 espressos / day) * Non-smoker or weaned for 3 months and total consumption \< 10 packs/year * With a BMI within \]18 - 25\[ kg/m². * Benefiting from a Social Security plan or benefiting from one through a third party * Giving free, informed and signed consent, after receiving clear and fair information about the study. Non-inclusion Criteria: * History of respiratory or ENT disease (asthma, chronic bronchitis, COPD, respiratory allergy, swallowing disorders, oropharyngeal malformation, obstructive or central sleep apnea-hypopnea syndrome, alveolar hypoventilation syndrome) * Respiratory, cardiovascular, muscular, neurological or diabetic pathology or disorders * Raynaud's disease/syndrome * History of epilepsy or history of malaise suggestive of epilepsy * Psychiatric history requiring hospitalization * Liver failure * Renal insufficiency * History of acute mountain sickness (presence during or after a stay at altitude of symptoms of vertigo, headache, nausea/vomiting and incapacitating fatigue: Lake Louise score \> 0) * History of migraines * Taking medications that interfere with respiratory function or cardiovascular function, or psychotropic drugs ( anxiolytic, sedative, antidepressant, neuroleptic, muscle relaxant, etc.). * Alcohol or drug dependence * Anemia, sickle-cell anemia * SpO2 \< 97% at rest in room air * Currently participating in another clinical study * Protected persons within the meaning of article L1121-5 to 8 (persons benefiting from enhanced protection, i.e. minors, persons deprived of their liberty by a judicial or administrative decision, pregnant or breast-feeding women, persons staying in a health or social establishment, adults under legal protection, and patients in emergency situations). - Women with childbearing capacity who do not have effective contraception (hormonal/mechanical: oral, injectable, transcutaneous, implantable, intrauterine device, or surgical: tubal ligation, hysterectomy, total oophorectomy). * Incidental finding of acute mountain sickness (Lake Louise score \>0) * Pregnant woman (incidental finding) * Persistence of average sleep time \< 6h * Non-reversible deterioration in volunteer's state of health within study period * Electroencephalogram signal unusable