A thermal tag includes a power source to generate current along a resistive path and a plurality of infrared-emitting features positioned along the resistive path to emit infrared light along an infrared-emitting pattern, wherein the plurality of infrared-emitting features include one or more infrared-emitting stripes on a first surface of the thermal tag defining a pattern region and a plurality of infrared-emitting dots within a portion of the pattern region to provide a thermal-diffusion resistant pattern for activity monitoring.