The present invention includes a device for hypoxia training including a breathable gas source； a mask in fluid communication with the breathable gas source； a mask-state detector that uses one or more criteria to determine if the mask is being worn by a subject, wherein the mask-state detector is capable of communicating an indication of a mask-off state or a mask-on state； a flowmeter in fluid communication with the mask and coupled to the mask-state detector； and a pressure regulator in fluid communication with the mask and with the breathable gas source, and coupled to the mask-state detector, wherein the pressure regulator sets a first pressure at the mask when the mask-state detector communicates an indication of a mask-off state or a second pressure at the mask when the mask-state detector communicates an indication of a mask-on state.
