The present disclosure pertains to a portable handheld pressure support system configured to deliver a blending gas enriched pressurized flow of breathable gas to the airway of a subject. The pressure support system is configured to treat patients suffering from dyspnea and/or other conditions. The therapy provided to dyspnea patients is configured to be used as needed by a subject to rapidly alleviate shortness of breath. The pressure support system is configured to be small and lightweight so that the subject may carry the system and use the system as needed without requiring a device to be worn on the face. In some embodiments, the system comprises one or more of a pressure generator, a subject interface, a blending gas inlet port, one or more sensors, a valve, one or more processors, a user interface, electronic storage, a portable power source, a housing, a handle, and/or other components.