The primary function of potassium in the body is to regulate fluid balance, support nerve function, and assist in muscle contractions. This essential mineral helps maintain cellular homeostasis by counteracting sodium effects, crucial for optimal heart and kidney function. Adequate potassium is vital for athletes, as it can prevent muscle cramps and enhance overall performance by ensuring proper muscle signaling during exercise. Foods rich in potassium include bananas, sweet potatoes, and spinach, making them excellent dietary choices for those aiming to support both general health and athletic endeavors.