Dehydration significantly impacts athletic performance by impairing physical and cognitive functions. A fluid deficit can lead to decreased endurance, strength, and coordination. Mild dehydration (1-2% body weight loss) can cause fatigue, reduced concentration, and muscle cramps. As dehydration progresses, the risk of heat-related illnesses increases, particularly in high-temperature environments. Therefore, maintaining proper hydration before, during, and after exercise is crucial for ensuring optimal performance and recovery, as well as preventing adverse health outcomes.