An exothermic reaction is a chemical process that releases energy, usually in the form of heat. This means that the products of the reaction have less energy than the reactants. Common examples include combustion, such as burning wood or fossil fuels, where energy is released into the environment. In everyday life, exothermic reactions are important in various applications. For instance, the heat generated by cellular respiration in living organisms helps maintain body temperature. Additionally, hand warmers utilize exothermic reactions to provide warmth in cold conditions, demonstrating their practical use in daily activities.