This document discusses thermoregulation, which is the body's ability to maintain its core temperature within a narrow range. It describes the four main methods of thermoregulation: conduction, convection, radiation, and evaporation. Evaporation of sweat is the most effective way for the body to lose heat. The document also discusses how environmental factors like temperature, humidity, and clothing can impact thermoregulation during exercise. Maintaining proper thermoregulation is important for athletic performance and preventing conditions like hyperthermia or hypothermia.