The primary function of hydration in physical performance is to maintain optimal body temperature, support cardiovascular function, and facilitate nutrient transport. Staying properly hydrated enables effective sweating, which cools the body during exercise. Moreover, adequate fluid intake is crucial for sustaining energy levels, preventing fatigue, and ensuring optimal muscle function. Dehydration can impair performance, cognition, and recovery times, emphasizing the importance of drinking enough fluids before, during, and after exercise for overall health and performance.