Described herein are embodiments of vacuum activated evacuatable medical positioners, warming devices for use with such positioners, systems that include a positioner and a warming device, and related methods. The disclosed embodiments include an electrical warming medium that is positioned, or adapted to be positioned, external to the patient-bearing side of an air-tight shell of a positioner. The electrical warming medium may be an integral part of a positioner, a part of a circumferential sleeve adapted to be placed around a positioner, or part of a pad adapted to be placed over a positioner, for example.
