The purpose of hydration during prolonged exercise is to maintain fluid balance, support thermoregulation, and enhance performance. During extended physical activity, the body loses fluids through sweat, which can lead to dehydration if not replenished. Adequate hydration aids in maintaining blood volume, stabilizes body temperature, and supports cardiovascular function. Dehydration can result in decreased stamina, increased fatigue, and impaired cognitive function, ultimately hindering exercise performance. Therefore, individuals should ensure they drink fluids before, during, and after exercise to optimize physical performance and prevent the negative consequences of dehydration.