Abstract: A garment that heats a portion of a human body during warm-up prior to athletic endeavor having a heater pad member with a size between the size of a common index card and an ordinary sheet of paper for localized penetrating heating of tissue and muscles. Heating is achieved by electrical heating of a heater pad member having a reflective metal foil on one side of the heater pad and thermally conductive PVF sheets on the opposite side. On the one hand, the metal foil reflects optical radiation toward a human body, while on the other hand, the PVF sheets direct infrared radiation into the human body. Control electronics, a battery and the heater pad are contained in separate pockets of the garment that are electrically connected together.