The present invention is directed to heating devices, and methods of treatment using the same, wherein the heating devices comprise (a) a polymer matrix comprising a matrix of: (i) at least one polymer and (ii) a plurality of electrically conductive particles distributed within the polymer and (b) two electrodes in electrical communication with the polymer matrix. The heating devices are highly portable and able to control the heating temperatures within precise limits for prolonged times without the use of any external thermostatic control device, using only low voltage batteries.
