Rebreather
(重定向自Breathing bag)

![Relation of physiological effects to carbon dioxide concentration and exposure period.[3]](/uploads/202501/01/Physiological_effects_of_carbon_dioxide_concentration_and_exposure_period0455.png)


A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from an open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment.