A substrate that is capable of generating heat upon activation is provided. Specifically, the substrate is applied with an exothermic coating that may be formed from a variety of different components, including oxidizable metals, carbon components, binders, electrolytic salts, moisture-retaining particles, and so forth. The oxidizable metal is capable of undergoing an exothermic reaction in the presence of oxygen and water to generate heat. To reduce the likelihood of premature activation prior to use, the exothermic coating is anhydrous, i.e., generally free of water. The coated substrate may be employed in a wide variety of articles, such as absorbent articles, thermal blankets, drapes, heating pads etc.