Electrolytes are crucial during prolonged physical activity as they help maintain fluid balance, nerve function, and muscle contractions. Key electrolytes include sodium, potassium, calcium, and magnesium, which are lost through sweat. Dehydration can lead to an imbalance of these electrolytes, resulting in symptoms such as muscle cramps, fatigue, and decreased athletic performance. Replenishing electrolytes through sports drinks or electrolyte-rich foods during and after intense activities is important for maintaining optimal hydration levels and supporting overall performance and health.