In this episode, we explore the physiological changes that occur during heat acclimatization, a process that develops over 3–14 days of repeated heat exposure. We discuss the benefits, including improved thermoregulation, increased plasma volume, and enhanced exercise performance. Key adaptations include increased sweat rate, earlier onset of sweating, and reduced sodium loss, all supported by the hormone aldosterone. These changes help individuals tolerate prolonged heat exposure, reducing the risk of heat-related illnesses. Applications for athletes, workers, and general populations emphasize the importance of hydration and consistent heat exposure.