The function of electrolytes in physical performance includes maintaining fluid balance, nerve function, and muscle contraction. Essential electrolytes, such as sodium, potassium, and calcium, help regulate hydration levels and are vital for proper muscle function. During exercise, individuals lose electrolytes through sweat, which can lead to imbalances affecting performance and endurance. Replenishing electrolytes before, during, and after exercise aids in preventing cramps and optimizing overall physical activity.