A respiration appliance configured to entrain the breathing of a subject, the respiration appliance comprising: one or more bodies configured to enclose one or more external orifices of the airway of a subject, wherein the one or more bodies form one or more flow paths between the enclosed one or more external orifices of the airway of the subject and ambient atmosphere; one or more valves (26, 28) disposed in the one or more bodies, the one or more valves (26, 28) being configured to provide ( i) a cumulative inhalation resistance to gas flow within the one or more flow paths formed by the one or more bodies to gas flowing from ambient atmosphere to the one or more external orifices of the airway of the subject enclosed by the one or more bodies, and ( ii) a cumulative exhalation resistance to gas flow within the one or more flow paths formed by the one or more bodies to gas flowing from the one or more external orifices of the airway of the subject enclosed by the one or more bodies to ambient atmosphere, wherein the cumulative inhalation resistance is low enough that the subject can inhale freely ambient atmosphere through the one or more bodies, and wherein the cumulative exhalation resistance is higher than the cumulative inhalation resistance, and is selected to restrict the exhalation of the subject to extend the exhalation time of the subject, thereby entraining the breathing of the subject while the subject is conscious to modulate the autonomic nervous system of the subject to decrease sympathetic nerve activity and/or reducing sympathetic/parasympathetic balance in order to provide relaxation to the subject; characterized in that the respiration appliance further comprises a training cue generator configured to generate breathing cues to the subject that prompt the subject to reduce a pressure differential between the one or more flow paths formed by the one or more bodies and ambient atmosphere only if the pressure differential breaches a threshold pressure differential. one or more bodies configured to enclose one or more external orifices of the airway of a subject, wherein the one or more bodies form one or more flow paths between the enclosed one or more external orifices of the airway of the subject and ambient atmosphere; one or more valves (26, 28) disposed in the one or more bodies, the one or more valves (26, 28) being configured to provide ( i) a cumulative inhalation resistance to gas flow within the one or more flow paths formed by the one or more bodies to gas flowing from ambient atmosphere to the one or more external orifices of the airway of the subject enclosed by the one or more bodies, and ( ii) a cumulative exhalation resistance to gas flow within the one or more flow paths formed by the one or more bodies to gas flowing from the one or more external orifices of the airway of the subject enclosed by the one or more bodies to ambient atmosphere, wherein the cumulative inhalation resistance is low enough that the subject can inhale freely ambient atmosphere through the one or more bodies, and wherein the cumulative exhalation resistance is higher than the cumulative inhalation resistance, and is selected to restrict the exhalation of the subject to extend the exhalation time of the subject, thereby entraining the breathing of the subject while the subject is conscious to modulate the autonomic nervous system of the subject to decrease sympathetic nerve activity and/or reducing sympathetic/parasympathetic balance in order to provide relaxation to the subject; characterized in that the respiration appliance further comprises a training cue generator configured to generate breathing cues to the subject that prompt the subject to reduce a pressure differential between the one or more flow paths formed by the one or more bodies and ambient atmosphere only if the pressure differential breaches a threshold pressure differential.