Periodic ventilation that includes CHEYNE Stokes ventilation is a pathological pattern characterized by alternating periods of hyperpneas and apnea-hypopneas. It occurs generally during sleep, at high altitude and in hypoxic conditions in healthy subjects, and in some diseases like congestive heart failure. One study conducted on an animal model suggested that baclofen, a drug already used against spasticity in humans, could also be effective against periodic ventilation. The goal of the study is therefore to assess this hypothesis on hypoxia-induced periodic ventilation in healthy subjects during sleep.